SizeCoding - User contributions [en]

Commodore Amiga

2026-03-03T15:00:00Z

Hitchhikr: /* Getting something on screen */

== Commodore Amiga ==
The Commodore Amiga system consists of the M68k system with custom hardware for graphics and sound.

=== Setting up ===

* Assembler: VASM
* Emulator(s): Linux: fs-uae, Windows: WinUAE

Compile source to Amiga Kickstart1.x executable:

<syntaxhighlight lang="">
vasm -kick1hunks -Fhunkexe -o example -nosym
</syntaxhighlight>

=== Amiga executable format ===
Commodore Amiga executables consist of a 32 byte header, as well as a 4 byte footer. Here's an example where deadc0de is the only code data. 0000 03f2 marks the end of the block.
<syntaxhighlight lang="">
00000000: 0000 03f3 0000 0000 0000 0001 0000 0000
00000010: 0000 0000 0000 0001 0000 03e9 0000 0001
00000020: dead c0de 0000 03f2
</syntaxhighlight>

=== Memory Map ===
Here is the amiga memory map
<gallery>
Amiga_memorymap.png
</gallery>

=== Video display ===
The Amiga OCS uses an interleaved planar memory layout to represent its various paletted display modes.

==== Getting something on screen ====
One of the shortest ways to get you started with getting anything on screen at all, is to initialize and use the intuition graphics library routines.
These are relatively easy to setup and allow you to plot pixels, circles, rects and even polygons.
However, as can be expected these routines are extremely slow in execution.

<syntaxhighlight lang="">
incdir "include"
include "graphics/graphics_lib.i"
include "intuition/screens.i"

move.l $170(a2),a6 ; intuitionbase from globvec
move.l ib_ActiveScreen(a6),a5 ; a5 = activeScreen (640x256 on most systems)
move.l $4.w,a6 ; execbase
move.l 156(a6),a6 ; graphics.library

; clear screen
lea sc_RastPort(a5),a1
jsr _LVOClearScreen(a6)

frameloop:
move.w #240-1,d7 ; y
yLoop:
move.w #640-1,d6 ; x
xLoop:
; Set Pixel/Pen Color (d0 = color)
move d6,d0 ; d0=x
eor d7,d0 ; d0=x^y
lsr #3,d0 ; d0>>=3
jsr _LVOSetAPen(a6)

; Write Pixel (d0=x, d1=y)
move d6,d0
move d7,d1
jsr _LVOWritePixel(a6)
dbra d6,xLoop
dbra d7,yLoop

bra frameloop
</syntaxhighlight>

==== Copperlist ====
Another way to start drawing things on screen is to setup a (minimal) copperlist with commands for one or more planes, which can be manipulated indiviually

Copper list format:
<syntaxhighlight lang="">
To be added
</syntaxhighlight>

As it happens, you can also insert color definition into the copperlist.

==== Planes ====
Every plane contains one bit of a pixel's colour index value. The bits of the binary representation of a colour index like %1010 (% Bit3,Bit2,Bit1,Bit0) will end up in 6 different planes (bits most significant to least significant aka left to right): Plane4 Plane3 Plane2 Plane1.

So basicly Plane1 contains all of the Bit0s of all pixels, Plane2 all Bit1s, Plane3 all Bit2s and Plane4 all Bit3s.

The first pixel on a plane is described by the leftmost (aka most significant) bit in a word, the second one by the second-leftmost etc. - just like this %0123456789abcdef with 0-f=pixels 1-16. %1000000000000000=$8000=pixel 1 in a plane word set. The 16th pixel will use the leftmost bit of the next word in this plane. etc.

==== Drawing pixels ====
Here are some examples for drawing pixels in 1 or more bitplanes:

1-bpp pixel plot
<syntaxhighlight lang="">
To be added
</syntaxhighlight>

2-bpp pixel plot
<syntaxhighlight lang="">
To be added
</syntaxhighlight>

==== Setting a palette====
The Amiga OCS uses index values into a palette of colours. Palette format is a word per index with 3 nibbles for 4-bit RGB (e.g. $00f for blue). Here is some code that will help you setup an entire palette at once using the intuition graphics routine.

<syntaxhighlight lang="">
lea sc_ViewPort(a5),a0
lea paldata(pc),a1
moveq #16,d0
jsr _LVOLoadRGB4(a6)

; Palette data
paldata:
dc.w $000,$100,$200,$311,$422,$533,$644,$755
dc.w $575,$464,$353,$242,$131,$020,$010,$000
</syntaxhighlight>

Alternatively you can set individual palette entries either by using a graphics function or using the copperlist for setting initial colors

=== Sound ===
To Paula chip (registers $DFF0A0-$DFF0DA) is able to output 8-bit PCM through a maximum of 4 channels.
Since the chip's dma is fed every horizontal scanline, you need to share cycles between the soundchip and other processes, impacting the maximum frequency or channels you can use at any given time.

The maximum audio buffer length is 65535 words (or about 128k of samples)

==== Make some noise ====
So, here is a bit of sound code that outputs a single channel sound.
<syntaxhighlight lang="">
move.l #pcmdata,$dff0a0 ; data to play (must be located in chipmem)
move.l #32<<16+(252*8),$dff0a4 ; length, period
move.w #64,$dff0a8 ; set volume
move.w #$8001,$dff096 ; enable audio channel 0
</syntaxhighlight>

=== Additional Resources ===
* [https://amycoders.org/ AmyCoders]
* [https://archive.org/details/Amiga_Hardware_Reference_Manual_1985_Commodore Amiga Harware Reference Manual from Commodore (scans on Archive.org)]
* [http://amigadev.elowar.com/read/ADCD_2.1/Hardware_Manual_guide/node0000.html Hardware Manual Guide]
* [https://wiki.amigaos.net/wiki/Graphics_Primitives/ Overview of Graphics primitives drawing]
* [https://www.markwrobel.dk/project/amigamachinecode/ Learning Amiga machine code]
* [https://heckmeck.de/demoscene/ Amiga coding Blogposts by Losso]
* [http://www.coppershade.org/articles/Code/Articles/ Coppershade articles]
* [http://amiga-dev.wikidot.com/file-format:hunk#toc7 Amiga Header information]
* [http://amiga-dev.wikidot.com/information:hardware Amiga Hardware registers overview]
* [https://github-wiki-see.page/m/echolevel/open-amiga-sampler/wiki/Appendix-A%3A-Sample-rates-deep-dive Paula Sample rates]

X68000

2026-02-12T07:26:52Z

Hitchhikr: /* Video display */

== Sharp X68000 ==
The Sharp X68000 is a home computer created by Sharp Corporation. It was first released in 1987 and sold only in Japan.

The initial model has a 10 MHz Motorola 68000 CPU, 1 MB of RAM, and lacks a hard drive. The final model was released in 1993 with a 25 MHz Motorola 68030 CPU, 4 MB of RAM, and optional 80 MB SCSI hard drive. RAM in these systems is expandable to 12 MB, though most games and applications do not require more than 2 MB.

The X68000 has graphics hardware similar to arcade video games of the late-1980s, with custom coprocessors supporting scrolling, tiled backgrounds, and large numbers of sprites. Sound is supplied through multiple sound chips supporting 8 channels of FM synthesis and one channel of adaptive differential pulse-code modulation audio, which are mixed down to 2 analog stereo channels via a DAC chip. As such, video gaming was a major use of the X68000.

The X68000 runs an operating system called Human68k which was developed for Sharp by Hudson Soft. An MS-DOS-workalike, Human68k features English-based commands very similar to those in MS-DOS;

=== Setting up ===
* Assembler: VASM
* Tools: NDC to create an XDF Disk Image containing the production
* Emulator(s): http://retropc.net/pi/xm6/index.html , https://www.retrostic.com/emulators/sharp-x68000/winx68030, https://mijet.eludevisibility.org/XM6%20Pro-68k/XM6%20Pro-68k.html
* Hardware: Original X68000 or the new X68000Z emulation systems.

=== Memory map ===

<syntaxhighlight lang="">
address vector Function
$000000 $00 SSP after reset
$000004 $01 PC after reset
$000008 $02 Bus error
$00000c $03 Address error
$000010 $04 Unknown instruction
$000014 $05 Division by 0
$000018 $06 CHK instruction
$00001c $07 TRAPV instruction, FTRAPcc instruction
$000020 $08 Privilege violation
$000024 $09 Trace exception
$000028 $0a Unsupported instruction line 1010 emulator (SX call)
$00002c $0b ? line 1111 emulator (DOS call, floating point operation)
$000030 $0c Unused
$000034 $0d FPU Protocol violation exception handling
$000038 $0e Formatting error exception handling
$00003c $0f Uninitialized Interrupt
$000040 $10 Unused
$000044 $11 ?
$000048 $12 ?
$00004c $13 ?
$000050 $14 ?
$000054 $15 ?
$000058 $16 ?
$00005c $17 ?
$000060 $18 Spurious Interrupt
$000064 $19 Level 1 Interrupt (auto vector)
$000068 $1a ?
$00006c $1b ?
$000070 $1c ?
$000074 $1d ?
$000078 $1e ?
$00007c $1f ?
$000080 $20 trap #0
$000084 $21 ? #1
$000088 $22 ? #2
$00008c $23 ? #3
$000090 $24 ? #4
$000094 $25 ? #5
$000098 $26 ? #6
$00009c $27 ? #7
$0000a0 $28 ? #8 (reserved for system)
$0000a4 $29 ? #9 (OS debugger)
$0000a8 $2a ? #10 (reset & power off)
$0000ac $2b ? #11 (BREAK key)
$0000b0 $2c ? #12 (COPY key)
$0000b4 $2d ? #13 (CTRL+C)
$0000b8 $2e ? #14 (error processing)
$0000bc $2f ? #15 (IOCS call)
$0000c0 $30 FPU BSUN
$0000c0 $30 FPU BSUN
$0000c4 $31 ? INEX1,INEX2
$0000c8 $32 ? DZ
$0000cc $33 ? UNFL
$0000d0 $34 ? OPERR
$0000d4 $35 ? OVFL
$0000d8 $36 ? SNAN
$0000dc $37 ???
$0000dc $37 Unused
$0000e0 $38 MMU
$0000e4 $39 ?
$0000e8 $3a ?
$0000ec $3b Unused
$0000fc $3f Unused
$000100 $40 MFP RTC Alarm/1Hz
$000104 $41 MFP External power OFF
$000118 $42 MFP Front switch OFF
$00010c $43 MFP FM Audio source
$000110 $44 MFP Timer-D (Used with BG processing)
$000114 $45 MFP Timer-C (Mouse/cursor/FDD control, etc.)
$000118 $46 MFP V-DISP
$00011c $47 MFP RTC Clock
$000120 $48 MFP Timer-B
$000124 $49 MFP Key serial output error
$000128 $4a MFP Key serial output empty
$00012c $4b MFP Key serial input error
$000130 $4c MFP Key serial input
$000134 $4d MFP Timer-A
$000138 $4e MFP CRTC*IRQ
$00013c $4f MFP H-SYNC
$000140 $50 SCC(B) Transmission buffer empty
$000144 $51 SCC(B) ''
$000148 $52 SCC(B) External/status changes
$00014c $53 SCC(B) ''
$000150 $54 SCC(B) Incoming character validity (Mouse 1 byte input)
$000154 $55 SCC(B) ''
$000158 $56 SCC(B) Special Rx condition
$00015c $57 SCC(B) ''
$000160 $58 SCC(A) Transmission buffer empty
$000164 $59 SCC(A) ''
$000168 $5a SCC(A) External status changes
$00016c $5b SCC(A) ''
$000170 $5c SCC(A) Incoming character validity (RS-232C 1 byte input)
$000174 $5d SCC(A) ''
$000178 $5e SCC(A) Special Rx Condition
$00017c $5f SCC(A) ''
$000180 $60 I/O FDC status interruption
$000184 $61 I/O FDC insertion/discharge interruption
$000188 $62 I/O HDC status interruption
$00018c $63 I/O Printer ready interruption
$000190 $64 DMAC #0 End (FDD)
$000194 $65 DMAC #0 Error ('')
$000198 $66 DMAC #1 End (SASI)
$00019c $67 DMAC #1 Error ('')
$0001a0 $68 DMAC #2 End (IOCS _DMAMOVE,_DMAMOV_A,_DMAMOV_L)
$0001a4 $69 DMAC #2 Error ('')
$0001a8 $6a DMAC #3 End (ADPCM)
$0001ac $6b DMAC #3 Error ('')
$000200 $6c SPC SCSI interruption (Internal SCSI)
$000204 $6d Unused
$0003d4 $f5 Unused
$0003d8 $f6 SPC SCSI interruption (SCSI board)
$0003dc $f7 Unused
$0003fc $ff Unused
0x000000 RAM area
$c00000 Graphics Vram � Page 0
$c80000 Graphics Vram � Page 1 (256/16 color only)
$d00000 Graphics Vram � Page 2 (16 color only)
$d80000 Graphics Vram � Page 3 (16 color only)
$e00000 Text Vram � Bitplane 0
$e20000 Text Vram � Bitplane 1
$e40000 Text Vram � Bitplane 2
$e60000 Text Vram � Bitplane 3
$e80000 1.w R00 Horizontal total
$e80002 1.w R01 Horizontal synchronization end position timing
$e80004 1.w R02 Horizontal display start position
$e80006 1.w R03 Horizontal display end position
$e80008 1.w R04 Vertical total
$e8000a 1.w R05 Vertical synchronization end position timing
$e8000c 1.w R06 Vertical display start position
$e8000e 1.w R07 Vertical display end position
$e80010 1.w R08 External synchronization horizontal adjust: Horizontal position tuning
$e80012 1.w R09 Raster number: Used for raster interruption
$e80014 1.w R10 Text Screen X coordinate
$e80016 1.w R11 Text Screen Y coordinate
$e80018 1.w R12 Graphics screen Scroll X0
$e8001a 1.w R13 Graphics screen Scroll Y0
$e8001c 1.w R14 Graphics screen Scroll X1
$e8001e 1.w R15 Graphics screen Scroll Y1
$e80020 1.w R16 Graphics screen Scroll X2
$e80022 1.w R17 Graphics screen Scroll Y2
$e80024 1.w R18 Graphics screen Scroll X3
$e80026 1.w R19 Graphics screen Scroll Y3
$e80028 1.w R20 Memory mode/Display mode control
$e8002a 1.w R21 Simultaneous access/Raster copy/Quick clear plane select
$e8002c 1.w R22 Raster copy action: Raster number
$e8002e 1.w R23 Text screen access mask pattern
$e80481 1.b Active Image capture/Quick clear/Raster copy control
$e82000 256.w Graphics palette
$e82200 16.w Text palette (Palette block 0)
$e82220 240.w Sprite palette ('' 1-15)
$e82400 1.w R0 (Screen mode initialization)
$e82500 1.w R1 (Priority control)
$e82600 1.w R2 (Special priority/screen display) - Layers On/Off
$e84000 DMAC (HD63450)
$e86000 Memory controller privileged access settings (OHM/ASA)
$e88000 MFP (MC68901)
$e8a000 RTC (RP5C15)
$e8c000 Printer port
$e8e001 #1 Contrast
$e8e003 #2 Display/3D Shutter Glasses (Bit 0=Right Eye / Bit 1 = Left Eye)
$e8e005 #3 Color image unit (bit 4-0)
$e8e007 #4 Keyboard/NMI/dot clock
$e8e009 #5 ROM/DRAM Wait
$e8e00b #6 MPU Classification/Operation clock
$e8e00d #7 SRAM Write
$e8e00f #8 Unit power OFF
$E90001 FM Synthesizer (YM2151) - Register Address Write port
$E90003 FM Synthesizer (YM2151) - Data R/W port
$E92000 ADPCM (MSM6258V)
$E94000 Floppy disk controller (FDC) (uPD72065)
$E94005 Floppy drive monitor (IOSC)
$E96000 SASI
$E98000 ESCC (Z8530)
$E9A000 PPI (82C55)
$E9C000 I/O selector (IOSC)
$E9E000 I/O expansion area (Sharp reserved)
$EB0000 Sprite register (CYNTHIA)
$EB8000 Sprite VRAM
$EC0000 I/O expansion area (User)
$ed0072 2.b SX-Window environment flag (While in use with "SX")
$ed0074 1.b Standard double-click time / 10
$ed0075 1.b Mouse speed / 2
$ed0076 1.b Text palette hue (HSV)
$ed0077 1.b
$ed0078 1.b Brightness palette 0-3 5bit???
$ed007b 1.b Printer drive (PRTD) ID
$ed007c 1.b SRAM info version#, screen status storage, start screen storage
$ed007d 1.b Desktop background (PICT) ID
$ed007e 1.b Screen mode
$ed007f 17.b Reserved for system use (X68030)
$ed0090 1.b Standard cache status (bit=0: off 1:on)
$ed0091 1.b OPM music during startup (0: OFF -1: ON)
$ed0092 1.b 10MHz Proper wait value
$ed0093 1.b 16MHz ''
$ed0094 108.b Reserved for system use
$ed0100 768.b Head SRAM program address
$ed0400 15KB Head SRAMDISK address
$ed3fff End of SRAM
$ed4000 Backup (64KB)
$ee0000 Unused (128KB)
$f00000 CGROM(768KB)
$fc0000 SCSI IOCS / IPL(8KB)
$fe0000 ROM Debugger
$ff0000 IPL / ROM IOCS
</syntaxhighlight>

=== Setting up the Disk Image ===
To get up and running, you need to create a Human68k OS XDF disk image, which is a similar system to MS-DOS.

Add the following files to the disk image:
<syntaxhighlight lang="">
COMMAND.X
HUMAN.SYS
INTRO.R (This is the flat binary output for your intro)
</syntaxhighlight>
Optionally, like in DOS, you can add a AUTOEXEC.BAT that just launches your INTRO.R for auto-startup.

=== Setting the Supervisor ===
Like all 68000 systems, if you want to access registers, you need to set the supervisor mode first before doing anything else:
<syntaxhighlight lang="">
clr.l -(a7)
dc.w $ff20
</syntaxhighlight>

=== Video display ===
To get your video mode up and running, there are two calls you need to make in a specific order

<syntaxhighlight lang="">
; Set CRT mode. Clears plane 0/1 on the text screen to set display mode.
; The graphics screen and sprite screen are put into silent mode without being cleared.
; The text palette is initialized.
moveq #10,d1
moveq #$10,d0
trap #15

; Enable graphics mode
; _G_CLR_ON Initializes the graphic screen and sets the display mode
; Clears the graphics screen and displays the palette. The page is set to 0.
moveq #-($100-$90),d0
trap #15

; Disable Text Cursor
moveq #$1f,d0
trap #15
</syntaxhighlight>

Here is a full list of all available graphics modes:
<syntaxhighlight lang="">
Mode Frequency Screen size Number of colors Actual screen size Number of pages

$0000 31 512x512 16 1024x1024 1
$0001 15 512x512 16 1024x1024 1
$0002 31 256x256 16 1024x1024 1
$0003 15 256x256 16 1024x1024 1
$0004 31 512x512 16 512x512 4
$0005 15 512x512 16 512x512 4
$0006 31 256x256 16 512x512 4
$0007 15 256x256 16 512x512 4
$0008 31 512x512 256 512x512 2
$0009 15 512x512 256 512x512 2
$000A 31 256x256 256 512x512 2
$000B 15 256x256 256 512x512 2
$000C 31 512x512 65536 512x512 1
$000D 15 512x512 65536 512x512 1
$000E 31 256x256 65536 512x512 1
$000F 15 256x256 65536 512x512 1
$0010 31 768x512 16 1024x1024 1
$0011 24 1024x424 16 1024x1024 1
$0012 24 1024x848 16 1024x1024 1
$0013 24 640x480 16 1024x1024 1
$0014 31 768x512 256 512x512 2
$0015 24 1024x424 256 512x512 2
$0016 24 1024x848 256 512x512 2
$0017 24 640x480 256 512x512 2
$0018 31 768x512 65536 512x512 1
$0019 24 1024x424 65536 512x512 1
$001A 24 1024x848 65536 512x512 1
$001B 24 640x480 65536 512x512 1

$0100 to $0113 Settings only, do not initialize
</syntaxhighlight>

==== Vsync ====
<syntaxhighlight lang="">
waitVBlank:
move.w $e88000,d0
and.w #%00010000,d0 ;Wait for vblank to start
beq waitVBlank
waitVBlank2:
move.w $e88000,d0
and.w #%00010000,d0 ;Wait for Vblank to end
bne waitVBlank2
rts
</syntaxhighlight>

==== Double buffering ====
You can use the following IOCS routines to set the active drawing and screenpages for double buffering.
<syntaxhighlight lang="">
; APAGE: Graphic drawing page settings
moveq #-($100-$b1),d0
moveq #0,d1 ; set page 0..3
trap #15

; VPAGE: Graphic screen display page setting
moveq #-($100-$b2),d0
moveq #0,d1 ; set page 0..3
trap #15
</syntaxhighlight>

==== Clearing the screen ====
You can clear the active page using the WIPE IOCS routine ($b5)
<syntaxhighlight lang="">
moveq #-($100-$b5),d0
trap #15
</syntaxhighlight>

==== Plotting to screen ====
When accessing using GRAM directly, you can fill the GVRAM directly in word (64k colors), byte (8 bit palette) or 4-bit 16 color mode.
<syntaxhighlight lang="">
lea GVRAM,a0
move.w #256-1,d7
moveq #1,d0
drawloop:
move.w d0,(a0)+
dbra d7,drawloop
</syntaxhighlight>
Since GVRAM buffer widths can differ from the resolution you are using, make sure to skip enough words at the end of each line to make up for the difference.

==== IOCS Drawing routines ====
Alternatively you could make use of the IOCS functions for drawing primitives using TRAP #15.
These are slow tom routines, compatible with all kinds of modes,
All these make use of a parameter buffer in A1 that you need to fill yourself with the correct information, for example for _PSET this would contain X,Y,COLOR like so:

<syntaxhighlight lang="">
lea params,a1
move.w d2,(a1) ; x-coord
move.w d3,2(a1) ; y-coord
move.w #255,4(a1) ; color
moveq #-($100-_PSET),d0
trap #15
</syntaxhighlight>

Here is a full list of other IOCS drawing routines you are able to use.
<syntaxhighlight lang="">
_PSET equ $b6
_POINT equ $b7
_LINE equ $b8
_BOX equ $b9
_FILL equ $ba
_CIRCLE equ $bb
_PAINT equ $bc
</syntaxhighlight>

=== Sound ===
The X68000 has a YM2151 FM Soundchip on board with 8 channels.
Each channel's sound can be built up with 4 different 'slots. There are a total of 32 slots that can be turned on or off when the sound is triggered. For more information, check out the YM2151 specs at [https://msxpro.com/datasheet.html]

Alternatively, there is also an option to output digital PCM sound.

=== Additional Resources ===
* [https://www.chibiakumas.com/68000/x68000.php Assembly programming for the X68000]
* [https://archive.org/details/X68000_488 X68000 Technical data book ]
* [https://msxpro.com/datasheet.html YM2151 Datasheet]
* [https://demozoo.org/productions/?platform=100 X68000 demoscene productions]
* [https://archive.org/details/cpsystem/page/202/mode/2up X68000 chapter in the book "The Book of CP-System"]
* [https://github.com/hitchhikr/xsdk X68000 Software Development Kit]

X68000

2026-02-12T07:21:23Z

Hitchhikr: /* Double buffering */

== Sharp X68000 ==
The Sharp X68000 is a home computer created by Sharp Corporation. It was first released in 1987 and sold only in Japan.

The initial model has a 10 MHz Motorola 68000 CPU, 1 MB of RAM, and lacks a hard drive. The final model was released in 1993 with a 25 MHz Motorola 68030 CPU, 4 MB of RAM, and optional 80 MB SCSI hard drive. RAM in these systems is expandable to 12 MB, though most games and applications do not require more than 2 MB.

The X68000 has graphics hardware similar to arcade video games of the late-1980s, with custom coprocessors supporting scrolling, tiled backgrounds, and large numbers of sprites. Sound is supplied through multiple sound chips supporting 8 channels of FM synthesis and one channel of adaptive differential pulse-code modulation audio, which are mixed down to 2 analog stereo channels via a DAC chip. As such, video gaming was a major use of the X68000.

The X68000 runs an operating system called Human68k which was developed for Sharp by Hudson Soft. An MS-DOS-workalike, Human68k features English-based commands very similar to those in MS-DOS;

=== Setting up ===
* Assembler: VASM
* Tools: NDC to create an XDF Disk Image containing the production
* Emulator(s): http://retropc.net/pi/xm6/index.html , https://www.retrostic.com/emulators/sharp-x68000/winx68030, https://mijet.eludevisibility.org/XM6%20Pro-68k/XM6%20Pro-68k.html
* Hardware: Original X68000 or the new X68000Z emulation systems.

=== Memory map ===

<syntaxhighlight lang="">
address vector Function
$000000 $00 SSP after reset
$000004 $01 PC after reset
$000008 $02 Bus error
$00000c $03 Address error
$000010 $04 Unknown instruction
$000014 $05 Division by 0
$000018 $06 CHK instruction
$00001c $07 TRAPV instruction, FTRAPcc instruction
$000020 $08 Privilege violation
$000024 $09 Trace exception
$000028 $0a Unsupported instruction line 1010 emulator (SX call)
$00002c $0b ? line 1111 emulator (DOS call, floating point operation)
$000030 $0c Unused
$000034 $0d FPU Protocol violation exception handling
$000038 $0e Formatting error exception handling
$00003c $0f Uninitialized Interrupt
$000040 $10 Unused
$000044 $11 ?
$000048 $12 ?
$00004c $13 ?
$000050 $14 ?
$000054 $15 ?
$000058 $16 ?
$00005c $17 ?
$000060 $18 Spurious Interrupt
$000064 $19 Level 1 Interrupt (auto vector)
$000068 $1a ?
$00006c $1b ?
$000070 $1c ?
$000074 $1d ?
$000078 $1e ?
$00007c $1f ?
$000080 $20 trap #0
$000084 $21 ? #1
$000088 $22 ? #2
$00008c $23 ? #3
$000090 $24 ? #4
$000094 $25 ? #5
$000098 $26 ? #6
$00009c $27 ? #7
$0000a0 $28 ? #8 (reserved for system)
$0000a4 $29 ? #9 (OS debugger)
$0000a8 $2a ? #10 (reset & power off)
$0000ac $2b ? #11 (BREAK key)
$0000b0 $2c ? #12 (COPY key)
$0000b4 $2d ? #13 (CTRL+C)
$0000b8 $2e ? #14 (error processing)
$0000bc $2f ? #15 (IOCS call)
$0000c0 $30 FPU BSUN
$0000c0 $30 FPU BSUN
$0000c4 $31 ? INEX1,INEX2
$0000c8 $32 ? DZ
$0000cc $33 ? UNFL
$0000d0 $34 ? OPERR
$0000d4 $35 ? OVFL
$0000d8 $36 ? SNAN
$0000dc $37 ???
$0000dc $37 Unused
$0000e0 $38 MMU
$0000e4 $39 ?
$0000e8 $3a ?
$0000ec $3b Unused
$0000fc $3f Unused
$000100 $40 MFP RTC Alarm/1Hz
$000104 $41 MFP External power OFF
$000118 $42 MFP Front switch OFF
$00010c $43 MFP FM Audio source
$000110 $44 MFP Timer-D (Used with BG processing)
$000114 $45 MFP Timer-C (Mouse/cursor/FDD control, etc.)
$000118 $46 MFP V-DISP
$00011c $47 MFP RTC Clock
$000120 $48 MFP Timer-B
$000124 $49 MFP Key serial output error
$000128 $4a MFP Key serial output empty
$00012c $4b MFP Key serial input error
$000130 $4c MFP Key serial input
$000134 $4d MFP Timer-A
$000138 $4e MFP CRTC*IRQ
$00013c $4f MFP H-SYNC
$000140 $50 SCC(B) Transmission buffer empty
$000144 $51 SCC(B) ''
$000148 $52 SCC(B) External/status changes
$00014c $53 SCC(B) ''
$000150 $54 SCC(B) Incoming character validity (Mouse 1 byte input)
$000154 $55 SCC(B) ''
$000158 $56 SCC(B) Special Rx condition
$00015c $57 SCC(B) ''
$000160 $58 SCC(A) Transmission buffer empty
$000164 $59 SCC(A) ''
$000168 $5a SCC(A) External status changes
$00016c $5b SCC(A) ''
$000170 $5c SCC(A) Incoming character validity (RS-232C 1 byte input)
$000174 $5d SCC(A) ''
$000178 $5e SCC(A) Special Rx Condition
$00017c $5f SCC(A) ''
$000180 $60 I/O FDC status interruption
$000184 $61 I/O FDC insertion/discharge interruption
$000188 $62 I/O HDC status interruption
$00018c $63 I/O Printer ready interruption
$000190 $64 DMAC #0 End (FDD)
$000194 $65 DMAC #0 Error ('')
$000198 $66 DMAC #1 End (SASI)
$00019c $67 DMAC #1 Error ('')
$0001a0 $68 DMAC #2 End (IOCS _DMAMOVE,_DMAMOV_A,_DMAMOV_L)
$0001a4 $69 DMAC #2 Error ('')
$0001a8 $6a DMAC #3 End (ADPCM)
$0001ac $6b DMAC #3 Error ('')
$000200 $6c SPC SCSI interruption (Internal SCSI)
$000204 $6d Unused
$0003d4 $f5 Unused
$0003d8 $f6 SPC SCSI interruption (SCSI board)
$0003dc $f7 Unused
$0003fc $ff Unused
0x000000 RAM area
$c00000 Graphics Vram � Page 0
$c80000 Graphics Vram � Page 1 (256/16 color only)
$d00000 Graphics Vram � Page 2 (16 color only)
$d80000 Graphics Vram � Page 3 (16 color only)
$e00000 Text Vram � Bitplane 0
$e20000 Text Vram � Bitplane 1
$e40000 Text Vram � Bitplane 2
$e60000 Text Vram � Bitplane 3
$e80000 1.w R00 Horizontal total
$e80002 1.w R01 Horizontal synchronization end position timing
$e80004 1.w R02 Horizontal display start position
$e80006 1.w R03 Horizontal display end position
$e80008 1.w R04 Vertical total
$e8000a 1.w R05 Vertical synchronization end position timing
$e8000c 1.w R06 Vertical display start position
$e8000e 1.w R07 Vertical display end position
$e80010 1.w R08 External synchronization horizontal adjust: Horizontal position tuning
$e80012 1.w R09 Raster number: Used for raster interruption
$e80014 1.w R10 Text Screen X coordinate
$e80016 1.w R11 Text Screen Y coordinate
$e80018 1.w R12 Graphics screen Scroll X0
$e8001a 1.w R13 Graphics screen Scroll Y0
$e8001c 1.w R14 Graphics screen Scroll X1
$e8001e 1.w R15 Graphics screen Scroll Y1
$e80020 1.w R16 Graphics screen Scroll X2
$e80022 1.w R17 Graphics screen Scroll Y2
$e80024 1.w R18 Graphics screen Scroll X3
$e80026 1.w R19 Graphics screen Scroll Y3
$e80028 1.w R20 Memory mode/Display mode control
$e8002a 1.w R21 Simultaneous access/Raster copy/Quick clear plane select
$e8002c 1.w R22 Raster copy action: Raster number
$e8002e 1.w R23 Text screen access mask pattern
$e80481 1.b Active Image capture/Quick clear/Raster copy control
$e82000 256.w Graphics palette
$e82200 16.w Text palette (Palette block 0)
$e82220 240.w Sprite palette ('' 1-15)
$e82400 1.w R0 (Screen mode initialization)
$e82500 1.w R1 (Priority control)
$e82600 1.w R2 (Special priority/screen display) - Layers On/Off
$e84000 DMAC (HD63450)
$e86000 Memory controller privileged access settings (OHM/ASA)
$e88000 MFP (MC68901)
$e8a000 RTC (RP5C15)
$e8c000 Printer port
$e8e001 #1 Contrast
$e8e003 #2 Display/3D Shutter Glasses (Bit 0=Right Eye / Bit 1 = Left Eye)
$e8e005 #3 Color image unit (bit 4-0)
$e8e007 #4 Keyboard/NMI/dot clock
$e8e009 #5 ROM/DRAM Wait
$e8e00b #6 MPU Classification/Operation clock
$e8e00d #7 SRAM Write
$e8e00f #8 Unit power OFF
$E90001 FM Synthesizer (YM2151) - Register Address Write port
$E90003 FM Synthesizer (YM2151) - Data R/W port
$E92000 ADPCM (MSM6258V)
$E94000 Floppy disk controller (FDC) (uPD72065)
$E94005 Floppy drive monitor (IOSC)
$E96000 SASI
$E98000 ESCC (Z8530)
$E9A000 PPI (82C55)
$E9C000 I/O selector (IOSC)
$E9E000 I/O expansion area (Sharp reserved)
$EB0000 Sprite register (CYNTHIA)
$EB8000 Sprite VRAM
$EC0000 I/O expansion area (User)
$ed0072 2.b SX-Window environment flag (While in use with "SX")
$ed0074 1.b Standard double-click time / 10
$ed0075 1.b Mouse speed / 2
$ed0076 1.b Text palette hue (HSV)
$ed0077 1.b
$ed0078 1.b Brightness palette 0-3 5bit???
$ed007b 1.b Printer drive (PRTD) ID
$ed007c 1.b SRAM info version#, screen status storage, start screen storage
$ed007d 1.b Desktop background (PICT) ID
$ed007e 1.b Screen mode
$ed007f 17.b Reserved for system use (X68030)
$ed0090 1.b Standard cache status (bit=0: off 1:on)
$ed0091 1.b OPM music during startup (0: OFF -1: ON)
$ed0092 1.b 10MHz Proper wait value
$ed0093 1.b 16MHz ''
$ed0094 108.b Reserved for system use
$ed0100 768.b Head SRAM program address
$ed0400 15KB Head SRAMDISK address
$ed3fff End of SRAM
$ed4000 Backup (64KB)
$ee0000 Unused (128KB)
$f00000 CGROM(768KB)
$fc0000 SCSI IOCS / IPL(8KB)
$fe0000 ROM Debugger
$ff0000 IPL / ROM IOCS
</syntaxhighlight>

=== Setting up the Disk Image ===
To get up and running, you need to create a Human68k OS XDF disk image, which is a similar system to MS-DOS.

Add the following files to the disk image:
<syntaxhighlight lang="">
COMMAND.X
HUMAN.SYS
INTRO.R (This is the flat binary output for your intro)
</syntaxhighlight>
Optionally, like in DOS, you can add a AUTOEXEC.BAT that just launches your INTRO.R for auto-startup.

=== Setting the Supervisor ===
Like all 68000 systems, if you want to access registers, you need to set the supervisor mode first before doing anything else:
<syntaxhighlight lang="">
clr.l -(a7)
dc.w $ff20
</syntaxhighlight>

=== Video display ===
To get your video mode up and running, there are two call you need to make in a specific order

<syntaxhighlight lang="">
; Set CRT mode. Clears plane 0/1 on the text screen to set display mode.
; The graphics screen and sprite screen are put into silent mode without being cleared.
; The text palette is initialized.
moveq #10,d1
moveq #$10,d0
trap #15

; Enable graphics mode
; _G_CLR_ON Initializes the graphic screen and sets the display mode
; Clears the graphics screen and displays the palette. The page is set to 0.
move.w #$90,d0
trap #15

; Disable Text Cursor
moveq #$1f,d0
trap #15
</syntaxhighlight>

Here is a full list of all available graphics modes:
<syntaxhighlight lang="">
d1.w p.width resolution colors screens khz
===================================================
0 1024 512 x 512 16 1 31
1 V V V V 15
2 V 256 x 256 V V 31
3 V V V V 15
4 512 512 x 512 16 4 31
5 V V V V 15
6 V 256 x 256 V V 31
7 V V V V 15
8 V 512 x 512 256 2 31
9 V V V V 15
10 V 256 x 256 V V 31
11 V V V V 15
12 V 512 x 512 65536 1 31
13 V V V V 15
14 V 256 x 256 V V 31
15 V V V V 15
16 1024 768 x 512 16 1 31
17 V 1024 x 424 V V 24
18 V 1024 x 848 V V 24
19 V 640 x 480 V V 24
20 V 768 x 512 256 2 31
21 V 1024 x 848 V V 24
22 V 1024 x 424 V V 24
23 V 640 x 480 V V 24
24 V 768 x 512 65536 1 31
25 V 1024 x 848 V V 24
26 V 1024 x 424 V V 24
27 V 640 x 480 V V 24
</syntaxhighlight>

==== Vsync ====
<syntaxhighlight lang="">
waitVBlank:
move.w $e88000,d0
and.w #%00010000,d0 ;Wait for vblank to start
beq waitVBlank
waitVBlank2:
move.w $e88000,d0
and.w #%00010000,d0 ;Wait for Vblank to end
bne waitVBlank2
rts
</syntaxhighlight>

==== Double buffering ====
You can use the following IOCS routines to set the active drawing and screenpages for double buffering.
<syntaxhighlight lang="">
; APAGE: Graphic drawing page settings
moveq #-($100-$b1),d0
moveq #0,d1 ; set page 0..3
trap #15

; VPAGE: Graphic screen display page setting
moveq #-($100-$b2),d0
moveq #0,d1 ; set page 0..3
trap #15
</syntaxhighlight>

==== Clearing the screen ====
You can clear the active page using the WIPE IOCS routine ($b5)
<syntaxhighlight lang="">
moveq #-($100-$b5),d0
trap #15
</syntaxhighlight>

==== Plotting to screen ====
When accessing using GRAM directly, you can fill the GVRAM directly in word (64k colors), byte (8 bit palette) or 4-bit 16 color mode.
<syntaxhighlight lang="">
lea GVRAM,a0
move.w #256-1,d7
moveq #1,d0
drawloop:
move.w d0,(a0)+
dbra d7,drawloop
</syntaxhighlight>
Since GVRAM buffer widths can differ from the resolution you are using, make sure to skip enough words at the end of each line to make up for the difference.

==== IOCS Drawing routines ====
Alternatively you could make use of the IOCS functions for drawing primitives using TRAP #15.
These are slow tom routines, compatible with all kinds of modes,
All these make use of a parameter buffer in A1 that you need to fill yourself with the correct information, for example for _PSET this would contain X,Y,COLOR like so:

<syntaxhighlight lang="">
lea params,a1
move.w d2,(a1) ; x-coord
move.w d3,2(a1) ; y-coord
move.w #255,4(a1) ; color
moveq #-($100-_PSET),d0
trap #15
</syntaxhighlight>

Here is a full list of other IOCS drawing routines you are able to use.
<syntaxhighlight lang="">
_PSET equ $b6
_POINT equ $b7
_LINE equ $b8
_BOX equ $b9
_FILL equ $ba
_CIRCLE equ $bb
_PAINT equ $bc
</syntaxhighlight>

=== Sound ===
The X68000 has a YM2151 FM Soundchip on board with 8 channels.
Each channel's sound can be built up with 4 different 'slots. There are a total of 32 slots that can be turned on or off when the sound is triggered. For more information, check out the YM2151 specs at [https://msxpro.com/datasheet.html]

Alternatively, there is also an option to output digital PCM sound.

=== Additional Resources ===
* [https://www.chibiakumas.com/68000/x68000.php Assembly programming for the X68000]
* [https://archive.org/details/X68000_488 X68000 Technical data book ]
* [https://msxpro.com/datasheet.html YM2151 Datasheet]
* [https://demozoo.org/productions/?platform=100 X68000 demoscene productions]
* [https://archive.org/details/cpsystem/page/202/mode/2up X68000 chapter in the book "The Book of CP-System"]
* [https://github.com/hitchhikr/xsdk X68000 Software Development Kit]

X68000

2026-02-12T07:20:57Z

Hitchhikr: /* Clearing the screen */

== Sharp X68000 ==
The Sharp X68000 is a home computer created by Sharp Corporation. It was first released in 1987 and sold only in Japan.

The initial model has a 10 MHz Motorola 68000 CPU, 1 MB of RAM, and lacks a hard drive. The final model was released in 1993 with a 25 MHz Motorola 68030 CPU, 4 MB of RAM, and optional 80 MB SCSI hard drive. RAM in these systems is expandable to 12 MB, though most games and applications do not require more than 2 MB.

The X68000 has graphics hardware similar to arcade video games of the late-1980s, with custom coprocessors supporting scrolling, tiled backgrounds, and large numbers of sprites. Sound is supplied through multiple sound chips supporting 8 channels of FM synthesis and one channel of adaptive differential pulse-code modulation audio, which are mixed down to 2 analog stereo channels via a DAC chip. As such, video gaming was a major use of the X68000.

The X68000 runs an operating system called Human68k which was developed for Sharp by Hudson Soft. An MS-DOS-workalike, Human68k features English-based commands very similar to those in MS-DOS;

=== Setting up ===
* Assembler: VASM
* Tools: NDC to create an XDF Disk Image containing the production
* Emulator(s): http://retropc.net/pi/xm6/index.html , https://www.retrostic.com/emulators/sharp-x68000/winx68030, https://mijet.eludevisibility.org/XM6%20Pro-68k/XM6%20Pro-68k.html
* Hardware: Original X68000 or the new X68000Z emulation systems.

=== Memory map ===

<syntaxhighlight lang="">
address vector Function
$000000 $00 SSP after reset
$000004 $01 PC after reset
$000008 $02 Bus error
$00000c $03 Address error
$000010 $04 Unknown instruction
$000014 $05 Division by 0
$000018 $06 CHK instruction
$00001c $07 TRAPV instruction, FTRAPcc instruction
$000020 $08 Privilege violation
$000024 $09 Trace exception
$000028 $0a Unsupported instruction line 1010 emulator (SX call)
$00002c $0b ? line 1111 emulator (DOS call, floating point operation)
$000030 $0c Unused
$000034 $0d FPU Protocol violation exception handling
$000038 $0e Formatting error exception handling
$00003c $0f Uninitialized Interrupt
$000040 $10 Unused
$000044 $11 ?
$000048 $12 ?
$00004c $13 ?
$000050 $14 ?
$000054 $15 ?
$000058 $16 ?
$00005c $17 ?
$000060 $18 Spurious Interrupt
$000064 $19 Level 1 Interrupt (auto vector)
$000068 $1a ?
$00006c $1b ?
$000070 $1c ?
$000074 $1d ?
$000078 $1e ?
$00007c $1f ?
$000080 $20 trap #0
$000084 $21 ? #1
$000088 $22 ? #2
$00008c $23 ? #3
$000090 $24 ? #4
$000094 $25 ? #5
$000098 $26 ? #6
$00009c $27 ? #7
$0000a0 $28 ? #8 (reserved for system)
$0000a4 $29 ? #9 (OS debugger)
$0000a8 $2a ? #10 (reset & power off)
$0000ac $2b ? #11 (BREAK key)
$0000b0 $2c ? #12 (COPY key)
$0000b4 $2d ? #13 (CTRL+C)
$0000b8 $2e ? #14 (error processing)
$0000bc $2f ? #15 (IOCS call)
$0000c0 $30 FPU BSUN
$0000c0 $30 FPU BSUN
$0000c4 $31 ? INEX1,INEX2
$0000c8 $32 ? DZ
$0000cc $33 ? UNFL
$0000d0 $34 ? OPERR
$0000d4 $35 ? OVFL
$0000d8 $36 ? SNAN
$0000dc $37 ???
$0000dc $37 Unused
$0000e0 $38 MMU
$0000e4 $39 ?
$0000e8 $3a ?
$0000ec $3b Unused
$0000fc $3f Unused
$000100 $40 MFP RTC Alarm/1Hz
$000104 $41 MFP External power OFF
$000118 $42 MFP Front switch OFF
$00010c $43 MFP FM Audio source
$000110 $44 MFP Timer-D (Used with BG processing)
$000114 $45 MFP Timer-C (Mouse/cursor/FDD control, etc.)
$000118 $46 MFP V-DISP
$00011c $47 MFP RTC Clock
$000120 $48 MFP Timer-B
$000124 $49 MFP Key serial output error
$000128 $4a MFP Key serial output empty
$00012c $4b MFP Key serial input error
$000130 $4c MFP Key serial input
$000134 $4d MFP Timer-A
$000138 $4e MFP CRTC*IRQ
$00013c $4f MFP H-SYNC
$000140 $50 SCC(B) Transmission buffer empty
$000144 $51 SCC(B) ''
$000148 $52 SCC(B) External/status changes
$00014c $53 SCC(B) ''
$000150 $54 SCC(B) Incoming character validity (Mouse 1 byte input)
$000154 $55 SCC(B) ''
$000158 $56 SCC(B) Special Rx condition
$00015c $57 SCC(B) ''
$000160 $58 SCC(A) Transmission buffer empty
$000164 $59 SCC(A) ''
$000168 $5a SCC(A) External status changes
$00016c $5b SCC(A) ''
$000170 $5c SCC(A) Incoming character validity (RS-232C 1 byte input)
$000174 $5d SCC(A) ''
$000178 $5e SCC(A) Special Rx Condition
$00017c $5f SCC(A) ''
$000180 $60 I/O FDC status interruption
$000184 $61 I/O FDC insertion/discharge interruption
$000188 $62 I/O HDC status interruption
$00018c $63 I/O Printer ready interruption
$000190 $64 DMAC #0 End (FDD)
$000194 $65 DMAC #0 Error ('')
$000198 $66 DMAC #1 End (SASI)
$00019c $67 DMAC #1 Error ('')
$0001a0 $68 DMAC #2 End (IOCS _DMAMOVE,_DMAMOV_A,_DMAMOV_L)
$0001a4 $69 DMAC #2 Error ('')
$0001a8 $6a DMAC #3 End (ADPCM)
$0001ac $6b DMAC #3 Error ('')
$000200 $6c SPC SCSI interruption (Internal SCSI)
$000204 $6d Unused
$0003d4 $f5 Unused
$0003d8 $f6 SPC SCSI interruption (SCSI board)
$0003dc $f7 Unused
$0003fc $ff Unused
0x000000 RAM area
$c00000 Graphics Vram � Page 0
$c80000 Graphics Vram � Page 1 (256/16 color only)
$d00000 Graphics Vram � Page 2 (16 color only)
$d80000 Graphics Vram � Page 3 (16 color only)
$e00000 Text Vram � Bitplane 0
$e20000 Text Vram � Bitplane 1
$e40000 Text Vram � Bitplane 2
$e60000 Text Vram � Bitplane 3
$e80000 1.w R00 Horizontal total
$e80002 1.w R01 Horizontal synchronization end position timing
$e80004 1.w R02 Horizontal display start position
$e80006 1.w R03 Horizontal display end position
$e80008 1.w R04 Vertical total
$e8000a 1.w R05 Vertical synchronization end position timing
$e8000c 1.w R06 Vertical display start position
$e8000e 1.w R07 Vertical display end position
$e80010 1.w R08 External synchronization horizontal adjust: Horizontal position tuning
$e80012 1.w R09 Raster number: Used for raster interruption
$e80014 1.w R10 Text Screen X coordinate
$e80016 1.w R11 Text Screen Y coordinate
$e80018 1.w R12 Graphics screen Scroll X0
$e8001a 1.w R13 Graphics screen Scroll Y0
$e8001c 1.w R14 Graphics screen Scroll X1
$e8001e 1.w R15 Graphics screen Scroll Y1
$e80020 1.w R16 Graphics screen Scroll X2
$e80022 1.w R17 Graphics screen Scroll Y2
$e80024 1.w R18 Graphics screen Scroll X3
$e80026 1.w R19 Graphics screen Scroll Y3
$e80028 1.w R20 Memory mode/Display mode control
$e8002a 1.w R21 Simultaneous access/Raster copy/Quick clear plane select
$e8002c 1.w R22 Raster copy action: Raster number
$e8002e 1.w R23 Text screen access mask pattern
$e80481 1.b Active Image capture/Quick clear/Raster copy control
$e82000 256.w Graphics palette
$e82200 16.w Text palette (Palette block 0)
$e82220 240.w Sprite palette ('' 1-15)
$e82400 1.w R0 (Screen mode initialization)
$e82500 1.w R1 (Priority control)
$e82600 1.w R2 (Special priority/screen display) - Layers On/Off
$e84000 DMAC (HD63450)
$e86000 Memory controller privileged access settings (OHM/ASA)
$e88000 MFP (MC68901)
$e8a000 RTC (RP5C15)
$e8c000 Printer port
$e8e001 #1 Contrast
$e8e003 #2 Display/3D Shutter Glasses (Bit 0=Right Eye / Bit 1 = Left Eye)
$e8e005 #3 Color image unit (bit 4-0)
$e8e007 #4 Keyboard/NMI/dot clock
$e8e009 #5 ROM/DRAM Wait
$e8e00b #6 MPU Classification/Operation clock
$e8e00d #7 SRAM Write
$e8e00f #8 Unit power OFF
$E90001 FM Synthesizer (YM2151) - Register Address Write port
$E90003 FM Synthesizer (YM2151) - Data R/W port
$E92000 ADPCM (MSM6258V)
$E94000 Floppy disk controller (FDC) (uPD72065)
$E94005 Floppy drive monitor (IOSC)
$E96000 SASI
$E98000 ESCC (Z8530)
$E9A000 PPI (82C55)
$E9C000 I/O selector (IOSC)
$E9E000 I/O expansion area (Sharp reserved)
$EB0000 Sprite register (CYNTHIA)
$EB8000 Sprite VRAM
$EC0000 I/O expansion area (User)
$ed0072 2.b SX-Window environment flag (While in use with "SX")
$ed0074 1.b Standard double-click time / 10
$ed0075 1.b Mouse speed / 2
$ed0076 1.b Text palette hue (HSV)
$ed0077 1.b
$ed0078 1.b Brightness palette 0-3 5bit???
$ed007b 1.b Printer drive (PRTD) ID
$ed007c 1.b SRAM info version#, screen status storage, start screen storage
$ed007d 1.b Desktop background (PICT) ID
$ed007e 1.b Screen mode
$ed007f 17.b Reserved for system use (X68030)
$ed0090 1.b Standard cache status (bit=0: off 1:on)
$ed0091 1.b OPM music during startup (0: OFF -1: ON)
$ed0092 1.b 10MHz Proper wait value
$ed0093 1.b 16MHz ''
$ed0094 108.b Reserved for system use
$ed0100 768.b Head SRAM program address
$ed0400 15KB Head SRAMDISK address
$ed3fff End of SRAM
$ed4000 Backup (64KB)
$ee0000 Unused (128KB)
$f00000 CGROM(768KB)
$fc0000 SCSI IOCS / IPL(8KB)
$fe0000 ROM Debugger
$ff0000 IPL / ROM IOCS
</syntaxhighlight>

=== Setting up the Disk Image ===
To get up and running, you need to create a Human68k OS XDF disk image, which is a similar system to MS-DOS.

Add the following files to the disk image:
<syntaxhighlight lang="">
COMMAND.X
HUMAN.SYS
INTRO.R (This is the flat binary output for your intro)
</syntaxhighlight>
Optionally, like in DOS, you can add a AUTOEXEC.BAT that just launches your INTRO.R for auto-startup.

=== Setting the Supervisor ===
Like all 68000 systems, if you want to access registers, you need to set the supervisor mode first before doing anything else:
<syntaxhighlight lang="">
clr.l -(a7)
dc.w $ff20
</syntaxhighlight>

=== Video display ===
To get your video mode up and running, there are two call you need to make in a specific order

<syntaxhighlight lang="">
; Set CRT mode. Clears plane 0/1 on the text screen to set display mode.
; The graphics screen and sprite screen are put into silent mode without being cleared.
; The text palette is initialized.
moveq #10,d1
moveq #$10,d0
trap #15

; Enable graphics mode
; _G_CLR_ON Initializes the graphic screen and sets the display mode
; Clears the graphics screen and displays the palette. The page is set to 0.
move.w #$90,d0
trap #15

; Disable Text Cursor
moveq #$1f,d0
trap #15
</syntaxhighlight>

Here is a full list of all available graphics modes:
<syntaxhighlight lang="">
d1.w p.width resolution colors screens khz
===================================================
0 1024 512 x 512 16 1 31
1 V V V V 15
2 V 256 x 256 V V 31
3 V V V V 15
4 512 512 x 512 16 4 31
5 V V V V 15
6 V 256 x 256 V V 31
7 V V V V 15
8 V 512 x 512 256 2 31
9 V V V V 15
10 V 256 x 256 V V 31
11 V V V V 15
12 V 512 x 512 65536 1 31
13 V V V V 15
14 V 256 x 256 V V 31
15 V V V V 15
16 1024 768 x 512 16 1 31
17 V 1024 x 424 V V 24
18 V 1024 x 848 V V 24
19 V 640 x 480 V V 24
20 V 768 x 512 256 2 31
21 V 1024 x 848 V V 24
22 V 1024 x 424 V V 24
23 V 640 x 480 V V 24
24 V 768 x 512 65536 1 31
25 V 1024 x 848 V V 24
26 V 1024 x 424 V V 24
27 V 640 x 480 V V 24
</syntaxhighlight>

==== Vsync ====
<syntaxhighlight lang="">
waitVBlank:
move.w $e88000,d0
and.w #%00010000,d0 ;Wait for vblank to start
beq waitVBlank
waitVBlank2:
move.w $e88000,d0
and.w #%00010000,d0 ;Wait for Vblank to end
bne waitVBlank2
rts
</syntaxhighlight>

==== Double buffering ====
You can use the following IOCS routines to set the active drawing and screenpages for double buffering.
<syntaxhighlight lang="">
; APAGE: Graphic drawing page settings
move.w #$b1,d0
moveq #0,d1 ; set page 0..3
trap #15

; VPAGE: Graphic screen display page setting
move.w #$b2,d0
moveq #0,d1 ; set page 0..3
trap #15
</syntaxhighlight>

==== Clearing the screen ====
You can clear the active page using the WIPE IOCS routine ($b5)
<syntaxhighlight lang="">
moveq #-($100-$b5),d0
trap #15
</syntaxhighlight>

==== Plotting to screen ====
When accessing using GRAM directly, you can fill the GVRAM directly in word (64k colors), byte (8 bit palette) or 4-bit 16 color mode.
<syntaxhighlight lang="">
lea GVRAM,a0
move.w #256-1,d7
moveq #1,d0
drawloop:
move.w d0,(a0)+
dbra d7,drawloop
</syntaxhighlight>
Since GVRAM buffer widths can differ from the resolution you are using, make sure to skip enough words at the end of each line to make up for the difference.

==== IOCS Drawing routines ====
Alternatively you could make use of the IOCS functions for drawing primitives using TRAP #15.
These are slow tom routines, compatible with all kinds of modes,
All these make use of a parameter buffer in A1 that you need to fill yourself with the correct information, for example for _PSET this would contain X,Y,COLOR like so:

<syntaxhighlight lang="">
lea params,a1
move.w d2,(a1) ; x-coord
move.w d3,2(a1) ; y-coord
move.w #255,4(a1) ; color
moveq #-($100-_PSET),d0
trap #15
</syntaxhighlight>

Here is a full list of other IOCS drawing routines you are able to use.
<syntaxhighlight lang="">
_PSET equ $b6
_POINT equ $b7
_LINE equ $b8
_BOX equ $b9
_FILL equ $ba
_CIRCLE equ $bb
_PAINT equ $bc
</syntaxhighlight>

=== Sound ===
The X68000 has a YM2151 FM Soundchip on board with 8 channels.
Each channel's sound can be built up with 4 different 'slots. There are a total of 32 slots that can be turned on or off when the sound is triggered. For more information, check out the YM2151 specs at [https://msxpro.com/datasheet.html]

Alternatively, there is also an option to output digital PCM sound.

=== Additional Resources ===
* [https://www.chibiakumas.com/68000/x68000.php Assembly programming for the X68000]
* [https://archive.org/details/X68000_488 X68000 Technical data book ]
* [https://msxpro.com/datasheet.html YM2151 Datasheet]
* [https://demozoo.org/productions/?platform=100 X68000 demoscene productions]
* [https://archive.org/details/cpsystem/page/202/mode/2up X68000 chapter in the book "The Book of CP-System"]
* [https://github.com/hitchhikr/xsdk X68000 Software Development Kit]

X68000

2026-02-12T07:20:36Z

Hitchhikr: /* Plotting to screen */

== Sharp X68000 ==
The Sharp X68000 is a home computer created by Sharp Corporation. It was first released in 1987 and sold only in Japan.

The initial model has a 10 MHz Motorola 68000 CPU, 1 MB of RAM, and lacks a hard drive. The final model was released in 1993 with a 25 MHz Motorola 68030 CPU, 4 MB of RAM, and optional 80 MB SCSI hard drive. RAM in these systems is expandable to 12 MB, though most games and applications do not require more than 2 MB.

The X68000 has graphics hardware similar to arcade video games of the late-1980s, with custom coprocessors supporting scrolling, tiled backgrounds, and large numbers of sprites. Sound is supplied through multiple sound chips supporting 8 channels of FM synthesis and one channel of adaptive differential pulse-code modulation audio, which are mixed down to 2 analog stereo channels via a DAC chip. As such, video gaming was a major use of the X68000.

The X68000 runs an operating system called Human68k which was developed for Sharp by Hudson Soft. An MS-DOS-workalike, Human68k features English-based commands very similar to those in MS-DOS;

=== Setting up ===
* Assembler: VASM
* Tools: NDC to create an XDF Disk Image containing the production
* Emulator(s): http://retropc.net/pi/xm6/index.html , https://www.retrostic.com/emulators/sharp-x68000/winx68030, https://mijet.eludevisibility.org/XM6%20Pro-68k/XM6%20Pro-68k.html
* Hardware: Original X68000 or the new X68000Z emulation systems.

=== Memory map ===

<syntaxhighlight lang="">
address vector Function
$000000 $00 SSP after reset
$000004 $01 PC after reset
$000008 $02 Bus error
$00000c $03 Address error
$000010 $04 Unknown instruction
$000014 $05 Division by 0
$000018 $06 CHK instruction
$00001c $07 TRAPV instruction, FTRAPcc instruction
$000020 $08 Privilege violation
$000024 $09 Trace exception
$000028 $0a Unsupported instruction line 1010 emulator (SX call)
$00002c $0b ? line 1111 emulator (DOS call, floating point operation)
$000030 $0c Unused
$000034 $0d FPU Protocol violation exception handling
$000038 $0e Formatting error exception handling
$00003c $0f Uninitialized Interrupt
$000040 $10 Unused
$000044 $11 ?
$000048 $12 ?
$00004c $13 ?
$000050 $14 ?
$000054 $15 ?
$000058 $16 ?
$00005c $17 ?
$000060 $18 Spurious Interrupt
$000064 $19 Level 1 Interrupt (auto vector)
$000068 $1a ?
$00006c $1b ?
$000070 $1c ?
$000074 $1d ?
$000078 $1e ?
$00007c $1f ?
$000080 $20 trap #0
$000084 $21 ? #1
$000088 $22 ? #2
$00008c $23 ? #3
$000090 $24 ? #4
$000094 $25 ? #5
$000098 $26 ? #6
$00009c $27 ? #7
$0000a0 $28 ? #8 (reserved for system)
$0000a4 $29 ? #9 (OS debugger)
$0000a8 $2a ? #10 (reset & power off)
$0000ac $2b ? #11 (BREAK key)
$0000b0 $2c ? #12 (COPY key)
$0000b4 $2d ? #13 (CTRL+C)
$0000b8 $2e ? #14 (error processing)
$0000bc $2f ? #15 (IOCS call)
$0000c0 $30 FPU BSUN
$0000c0 $30 FPU BSUN
$0000c4 $31 ? INEX1,INEX2
$0000c8 $32 ? DZ
$0000cc $33 ? UNFL
$0000d0 $34 ? OPERR
$0000d4 $35 ? OVFL
$0000d8 $36 ? SNAN
$0000dc $37 ???
$0000dc $37 Unused
$0000e0 $38 MMU
$0000e4 $39 ?
$0000e8 $3a ?
$0000ec $3b Unused
$0000fc $3f Unused
$000100 $40 MFP RTC Alarm/1Hz
$000104 $41 MFP External power OFF
$000118 $42 MFP Front switch OFF
$00010c $43 MFP FM Audio source
$000110 $44 MFP Timer-D (Used with BG processing)
$000114 $45 MFP Timer-C (Mouse/cursor/FDD control, etc.)
$000118 $46 MFP V-DISP
$00011c $47 MFP RTC Clock
$000120 $48 MFP Timer-B
$000124 $49 MFP Key serial output error
$000128 $4a MFP Key serial output empty
$00012c $4b MFP Key serial input error
$000130 $4c MFP Key serial input
$000134 $4d MFP Timer-A
$000138 $4e MFP CRTC*IRQ
$00013c $4f MFP H-SYNC
$000140 $50 SCC(B) Transmission buffer empty
$000144 $51 SCC(B) ''
$000148 $52 SCC(B) External/status changes
$00014c $53 SCC(B) ''
$000150 $54 SCC(B) Incoming character validity (Mouse 1 byte input)
$000154 $55 SCC(B) ''
$000158 $56 SCC(B) Special Rx condition
$00015c $57 SCC(B) ''
$000160 $58 SCC(A) Transmission buffer empty
$000164 $59 SCC(A) ''
$000168 $5a SCC(A) External status changes
$00016c $5b SCC(A) ''
$000170 $5c SCC(A) Incoming character validity (RS-232C 1 byte input)
$000174 $5d SCC(A) ''
$000178 $5e SCC(A) Special Rx Condition
$00017c $5f SCC(A) ''
$000180 $60 I/O FDC status interruption
$000184 $61 I/O FDC insertion/discharge interruption
$000188 $62 I/O HDC status interruption
$00018c $63 I/O Printer ready interruption
$000190 $64 DMAC #0 End (FDD)
$000194 $65 DMAC #0 Error ('')
$000198 $66 DMAC #1 End (SASI)
$00019c $67 DMAC #1 Error ('')
$0001a0 $68 DMAC #2 End (IOCS _DMAMOVE,_DMAMOV_A,_DMAMOV_L)
$0001a4 $69 DMAC #2 Error ('')
$0001a8 $6a DMAC #3 End (ADPCM)
$0001ac $6b DMAC #3 Error ('')
$000200 $6c SPC SCSI interruption (Internal SCSI)
$000204 $6d Unused
$0003d4 $f5 Unused
$0003d8 $f6 SPC SCSI interruption (SCSI board)
$0003dc $f7 Unused
$0003fc $ff Unused
0x000000 RAM area
$c00000 Graphics Vram � Page 0
$c80000 Graphics Vram � Page 1 (256/16 color only)
$d00000 Graphics Vram � Page 2 (16 color only)
$d80000 Graphics Vram � Page 3 (16 color only)
$e00000 Text Vram � Bitplane 0
$e20000 Text Vram � Bitplane 1
$e40000 Text Vram � Bitplane 2
$e60000 Text Vram � Bitplane 3
$e80000 1.w R00 Horizontal total
$e80002 1.w R01 Horizontal synchronization end position timing
$e80004 1.w R02 Horizontal display start position
$e80006 1.w R03 Horizontal display end position
$e80008 1.w R04 Vertical total
$e8000a 1.w R05 Vertical synchronization end position timing
$e8000c 1.w R06 Vertical display start position
$e8000e 1.w R07 Vertical display end position
$e80010 1.w R08 External synchronization horizontal adjust: Horizontal position tuning
$e80012 1.w R09 Raster number: Used for raster interruption
$e80014 1.w R10 Text Screen X coordinate
$e80016 1.w R11 Text Screen Y coordinate
$e80018 1.w R12 Graphics screen Scroll X0
$e8001a 1.w R13 Graphics screen Scroll Y0
$e8001c 1.w R14 Graphics screen Scroll X1
$e8001e 1.w R15 Graphics screen Scroll Y1
$e80020 1.w R16 Graphics screen Scroll X2
$e80022 1.w R17 Graphics screen Scroll Y2
$e80024 1.w R18 Graphics screen Scroll X3
$e80026 1.w R19 Graphics screen Scroll Y3
$e80028 1.w R20 Memory mode/Display mode control
$e8002a 1.w R21 Simultaneous access/Raster copy/Quick clear plane select
$e8002c 1.w R22 Raster copy action: Raster number
$e8002e 1.w R23 Text screen access mask pattern
$e80481 1.b Active Image capture/Quick clear/Raster copy control
$e82000 256.w Graphics palette
$e82200 16.w Text palette (Palette block 0)
$e82220 240.w Sprite palette ('' 1-15)
$e82400 1.w R0 (Screen mode initialization)
$e82500 1.w R1 (Priority control)
$e82600 1.w R2 (Special priority/screen display) - Layers On/Off
$e84000 DMAC (HD63450)
$e86000 Memory controller privileged access settings (OHM/ASA)
$e88000 MFP (MC68901)
$e8a000 RTC (RP5C15)
$e8c000 Printer port
$e8e001 #1 Contrast
$e8e003 #2 Display/3D Shutter Glasses (Bit 0=Right Eye / Bit 1 = Left Eye)
$e8e005 #3 Color image unit (bit 4-0)
$e8e007 #4 Keyboard/NMI/dot clock
$e8e009 #5 ROM/DRAM Wait
$e8e00b #6 MPU Classification/Operation clock
$e8e00d #7 SRAM Write
$e8e00f #8 Unit power OFF
$E90001 FM Synthesizer (YM2151) - Register Address Write port
$E90003 FM Synthesizer (YM2151) - Data R/W port
$E92000 ADPCM (MSM6258V)
$E94000 Floppy disk controller (FDC) (uPD72065)
$E94005 Floppy drive monitor (IOSC)
$E96000 SASI
$E98000 ESCC (Z8530)
$E9A000 PPI (82C55)
$E9C000 I/O selector (IOSC)
$E9E000 I/O expansion area (Sharp reserved)
$EB0000 Sprite register (CYNTHIA)
$EB8000 Sprite VRAM
$EC0000 I/O expansion area (User)
$ed0072 2.b SX-Window environment flag (While in use with "SX")
$ed0074 1.b Standard double-click time / 10
$ed0075 1.b Mouse speed / 2
$ed0076 1.b Text palette hue (HSV)
$ed0077 1.b
$ed0078 1.b Brightness palette 0-3 5bit???
$ed007b 1.b Printer drive (PRTD) ID
$ed007c 1.b SRAM info version#, screen status storage, start screen storage
$ed007d 1.b Desktop background (PICT) ID
$ed007e 1.b Screen mode
$ed007f 17.b Reserved for system use (X68030)
$ed0090 1.b Standard cache status (bit=0: off 1:on)
$ed0091 1.b OPM music during startup (0: OFF -1: ON)
$ed0092 1.b 10MHz Proper wait value
$ed0093 1.b 16MHz ''
$ed0094 108.b Reserved for system use
$ed0100 768.b Head SRAM program address
$ed0400 15KB Head SRAMDISK address
$ed3fff End of SRAM
$ed4000 Backup (64KB)
$ee0000 Unused (128KB)
$f00000 CGROM(768KB)
$fc0000 SCSI IOCS / IPL(8KB)
$fe0000 ROM Debugger
$ff0000 IPL / ROM IOCS
</syntaxhighlight>

=== Setting up the Disk Image ===
To get up and running, you need to create a Human68k OS XDF disk image, which is a similar system to MS-DOS.

Add the following files to the disk image:
<syntaxhighlight lang="">
COMMAND.X
HUMAN.SYS
INTRO.R (This is the flat binary output for your intro)
</syntaxhighlight>
Optionally, like in DOS, you can add a AUTOEXEC.BAT that just launches your INTRO.R for auto-startup.

=== Setting the Supervisor ===
Like all 68000 systems, if you want to access registers, you need to set the supervisor mode first before doing anything else:
<syntaxhighlight lang="">
clr.l -(a7)
dc.w $ff20
</syntaxhighlight>

=== Video display ===
To get your video mode up and running, there are two call you need to make in a specific order

<syntaxhighlight lang="">
; Set CRT mode. Clears plane 0/1 on the text screen to set display mode.
; The graphics screen and sprite screen are put into silent mode without being cleared.
; The text palette is initialized.
moveq #10,d1
moveq #$10,d0
trap #15

; Enable graphics mode
; _G_CLR_ON Initializes the graphic screen and sets the display mode
; Clears the graphics screen and displays the palette. The page is set to 0.
move.w #$90,d0
trap #15

; Disable Text Cursor
moveq #$1f,d0
trap #15
</syntaxhighlight>

Here is a full list of all available graphics modes:
<syntaxhighlight lang="">
d1.w p.width resolution colors screens khz
===================================================
0 1024 512 x 512 16 1 31
1 V V V V 15
2 V 256 x 256 V V 31
3 V V V V 15
4 512 512 x 512 16 4 31
5 V V V V 15
6 V 256 x 256 V V 31
7 V V V V 15
8 V 512 x 512 256 2 31
9 V V V V 15
10 V 256 x 256 V V 31
11 V V V V 15
12 V 512 x 512 65536 1 31
13 V V V V 15
14 V 256 x 256 V V 31
15 V V V V 15
16 1024 768 x 512 16 1 31
17 V 1024 x 424 V V 24
18 V 1024 x 848 V V 24
19 V 640 x 480 V V 24
20 V 768 x 512 256 2 31
21 V 1024 x 848 V V 24
22 V 1024 x 424 V V 24
23 V 640 x 480 V V 24
24 V 768 x 512 65536 1 31
25 V 1024 x 848 V V 24
26 V 1024 x 424 V V 24
27 V 640 x 480 V V 24
</syntaxhighlight>

==== Vsync ====
<syntaxhighlight lang="">
waitVBlank:
move.w $e88000,d0
and.w #%00010000,d0 ;Wait for vblank to start
beq waitVBlank
waitVBlank2:
move.w $e88000,d0
and.w #%00010000,d0 ;Wait for Vblank to end
bne waitVBlank2
rts
</syntaxhighlight>

==== Double buffering ====
You can use the following IOCS routines to set the active drawing and screenpages for double buffering.
<syntaxhighlight lang="">
; APAGE: Graphic drawing page settings
move.w #$b1,d0
moveq #0,d1 ; set page 0..3
trap #15

; VPAGE: Graphic screen display page setting
move.w #$b2,d0
moveq #0,d1 ; set page 0..3
trap #15
</syntaxhighlight>

==== Clearing the screen ====
You can clear the active page using the WIPE IOCS routine ($b5)
<syntaxhighlight lang="">
move.w #$b5,d0
trap #15
</syntaxhighlight>

==== Plotting to screen ====
When accessing using GRAM directly, you can fill the GVRAM directly in word (64k colors), byte (8 bit palette) or 4-bit 16 color mode.
<syntaxhighlight lang="">
lea GVRAM,a0
move.w #256-1,d7
moveq #1,d0
drawloop:
move.w d0,(a0)+
dbra d7,drawloop
</syntaxhighlight>
Since GVRAM buffer widths can differ from the resolution you are using, make sure to skip enough words at the end of each line to make up for the difference.

==== IOCS Drawing routines ====
Alternatively you could make use of the IOCS functions for drawing primitives using TRAP #15.
These are slow tom routines, compatible with all kinds of modes,
All these make use of a parameter buffer in A1 that you need to fill yourself with the correct information, for example for _PSET this would contain X,Y,COLOR like so:

<syntaxhighlight lang="">
lea params,a1
move.w d2,(a1) ; x-coord
move.w d3,2(a1) ; y-coord
move.w #255,4(a1) ; color
moveq #-($100-_PSET),d0
trap #15
</syntaxhighlight>

Here is a full list of other IOCS drawing routines you are able to use.
<syntaxhighlight lang="">
_PSET equ $b6
_POINT equ $b7
_LINE equ $b8
_BOX equ $b9
_FILL equ $ba
_CIRCLE equ $bb
_PAINT equ $bc
</syntaxhighlight>

=== Sound ===
The X68000 has a YM2151 FM Soundchip on board with 8 channels.
Each channel's sound can be built up with 4 different 'slots. There are a total of 32 slots that can be turned on or off when the sound is triggered. For more information, check out the YM2151 specs at [https://msxpro.com/datasheet.html]

Alternatively, there is also an option to output digital PCM sound.

=== Additional Resources ===
* [https://www.chibiakumas.com/68000/x68000.php Assembly programming for the X68000]
* [https://archive.org/details/X68000_488 X68000 Technical data book ]
* [https://msxpro.com/datasheet.html YM2151 Datasheet]
* [https://demozoo.org/productions/?platform=100 X68000 demoscene productions]
* [https://archive.org/details/cpsystem/page/202/mode/2up X68000 chapter in the book "The Book of CP-System"]
* [https://github.com/hitchhikr/xsdk X68000 Software Development Kit]

X68000

2026-02-12T07:19:40Z

Hitchhikr: /* IOCS Drawing routines */

== Sharp X68000 ==
The Sharp X68000 is a home computer created by Sharp Corporation. It was first released in 1987 and sold only in Japan.

The initial model has a 10 MHz Motorola 68000 CPU, 1 MB of RAM, and lacks a hard drive. The final model was released in 1993 with a 25 MHz Motorola 68030 CPU, 4 MB of RAM, and optional 80 MB SCSI hard drive. RAM in these systems is expandable to 12 MB, though most games and applications do not require more than 2 MB.

The X68000 has graphics hardware similar to arcade video games of the late-1980s, with custom coprocessors supporting scrolling, tiled backgrounds, and large numbers of sprites. Sound is supplied through multiple sound chips supporting 8 channels of FM synthesis and one channel of adaptive differential pulse-code modulation audio, which are mixed down to 2 analog stereo channels via a DAC chip. As such, video gaming was a major use of the X68000.

The X68000 runs an operating system called Human68k which was developed for Sharp by Hudson Soft. An MS-DOS-workalike, Human68k features English-based commands very similar to those in MS-DOS;

=== Setting up ===
* Assembler: VASM
* Tools: NDC to create an XDF Disk Image containing the production
* Emulator(s): http://retropc.net/pi/xm6/index.html , https://www.retrostic.com/emulators/sharp-x68000/winx68030, https://mijet.eludevisibility.org/XM6%20Pro-68k/XM6%20Pro-68k.html
* Hardware: Original X68000 or the new X68000Z emulation systems.

=== Memory map ===

<syntaxhighlight lang="">
address vector Function
$000000 $00 SSP after reset
$000004 $01 PC after reset
$000008 $02 Bus error
$00000c $03 Address error
$000010 $04 Unknown instruction
$000014 $05 Division by 0
$000018 $06 CHK instruction
$00001c $07 TRAPV instruction, FTRAPcc instruction
$000020 $08 Privilege violation
$000024 $09 Trace exception
$000028 $0a Unsupported instruction line 1010 emulator (SX call)
$00002c $0b ? line 1111 emulator (DOS call, floating point operation)
$000030 $0c Unused
$000034 $0d FPU Protocol violation exception handling
$000038 $0e Formatting error exception handling
$00003c $0f Uninitialized Interrupt
$000040 $10 Unused
$000044 $11 ?
$000048 $12 ?
$00004c $13 ?
$000050 $14 ?
$000054 $15 ?
$000058 $16 ?
$00005c $17 ?
$000060 $18 Spurious Interrupt
$000064 $19 Level 1 Interrupt (auto vector)
$000068 $1a ?
$00006c $1b ?
$000070 $1c ?
$000074 $1d ?
$000078 $1e ?
$00007c $1f ?
$000080 $20 trap #0
$000084 $21 ? #1
$000088 $22 ? #2
$00008c $23 ? #3
$000090 $24 ? #4
$000094 $25 ? #5
$000098 $26 ? #6
$00009c $27 ? #7
$0000a0 $28 ? #8 (reserved for system)
$0000a4 $29 ? #9 (OS debugger)
$0000a8 $2a ? #10 (reset & power off)
$0000ac $2b ? #11 (BREAK key)
$0000b0 $2c ? #12 (COPY key)
$0000b4 $2d ? #13 (CTRL+C)
$0000b8 $2e ? #14 (error processing)
$0000bc $2f ? #15 (IOCS call)
$0000c0 $30 FPU BSUN
$0000c0 $30 FPU BSUN
$0000c4 $31 ? INEX1,INEX2
$0000c8 $32 ? DZ
$0000cc $33 ? UNFL
$0000d0 $34 ? OPERR
$0000d4 $35 ? OVFL
$0000d8 $36 ? SNAN
$0000dc $37 ???
$0000dc $37 Unused
$0000e0 $38 MMU
$0000e4 $39 ?
$0000e8 $3a ?
$0000ec $3b Unused
$0000fc $3f Unused
$000100 $40 MFP RTC Alarm/1Hz
$000104 $41 MFP External power OFF
$000118 $42 MFP Front switch OFF
$00010c $43 MFP FM Audio source
$000110 $44 MFP Timer-D (Used with BG processing)
$000114 $45 MFP Timer-C (Mouse/cursor/FDD control, etc.)
$000118 $46 MFP V-DISP
$00011c $47 MFP RTC Clock
$000120 $48 MFP Timer-B
$000124 $49 MFP Key serial output error
$000128 $4a MFP Key serial output empty
$00012c $4b MFP Key serial input error
$000130 $4c MFP Key serial input
$000134 $4d MFP Timer-A
$000138 $4e MFP CRTC*IRQ
$00013c $4f MFP H-SYNC
$000140 $50 SCC(B) Transmission buffer empty
$000144 $51 SCC(B) ''
$000148 $52 SCC(B) External/status changes
$00014c $53 SCC(B) ''
$000150 $54 SCC(B) Incoming character validity (Mouse 1 byte input)
$000154 $55 SCC(B) ''
$000158 $56 SCC(B) Special Rx condition
$00015c $57 SCC(B) ''
$000160 $58 SCC(A) Transmission buffer empty
$000164 $59 SCC(A) ''
$000168 $5a SCC(A) External status changes
$00016c $5b SCC(A) ''
$000170 $5c SCC(A) Incoming character validity (RS-232C 1 byte input)
$000174 $5d SCC(A) ''
$000178 $5e SCC(A) Special Rx Condition
$00017c $5f SCC(A) ''
$000180 $60 I/O FDC status interruption
$000184 $61 I/O FDC insertion/discharge interruption
$000188 $62 I/O HDC status interruption
$00018c $63 I/O Printer ready interruption
$000190 $64 DMAC #0 End (FDD)
$000194 $65 DMAC #0 Error ('')
$000198 $66 DMAC #1 End (SASI)
$00019c $67 DMAC #1 Error ('')
$0001a0 $68 DMAC #2 End (IOCS _DMAMOVE,_DMAMOV_A,_DMAMOV_L)
$0001a4 $69 DMAC #2 Error ('')
$0001a8 $6a DMAC #3 End (ADPCM)
$0001ac $6b DMAC #3 Error ('')
$000200 $6c SPC SCSI interruption (Internal SCSI)
$000204 $6d Unused
$0003d4 $f5 Unused
$0003d8 $f6 SPC SCSI interruption (SCSI board)
$0003dc $f7 Unused
$0003fc $ff Unused
0x000000 RAM area
$c00000 Graphics Vram � Page 0
$c80000 Graphics Vram � Page 1 (256/16 color only)
$d00000 Graphics Vram � Page 2 (16 color only)
$d80000 Graphics Vram � Page 3 (16 color only)
$e00000 Text Vram � Bitplane 0
$e20000 Text Vram � Bitplane 1
$e40000 Text Vram � Bitplane 2
$e60000 Text Vram � Bitplane 3
$e80000 1.w R00 Horizontal total
$e80002 1.w R01 Horizontal synchronization end position timing
$e80004 1.w R02 Horizontal display start position
$e80006 1.w R03 Horizontal display end position
$e80008 1.w R04 Vertical total
$e8000a 1.w R05 Vertical synchronization end position timing
$e8000c 1.w R06 Vertical display start position
$e8000e 1.w R07 Vertical display end position
$e80010 1.w R08 External synchronization horizontal adjust: Horizontal position tuning
$e80012 1.w R09 Raster number: Used for raster interruption
$e80014 1.w R10 Text Screen X coordinate
$e80016 1.w R11 Text Screen Y coordinate
$e80018 1.w R12 Graphics screen Scroll X0
$e8001a 1.w R13 Graphics screen Scroll Y0
$e8001c 1.w R14 Graphics screen Scroll X1
$e8001e 1.w R15 Graphics screen Scroll Y1
$e80020 1.w R16 Graphics screen Scroll X2
$e80022 1.w R17 Graphics screen Scroll Y2
$e80024 1.w R18 Graphics screen Scroll X3
$e80026 1.w R19 Graphics screen Scroll Y3
$e80028 1.w R20 Memory mode/Display mode control
$e8002a 1.w R21 Simultaneous access/Raster copy/Quick clear plane select
$e8002c 1.w R22 Raster copy action: Raster number
$e8002e 1.w R23 Text screen access mask pattern
$e80481 1.b Active Image capture/Quick clear/Raster copy control
$e82000 256.w Graphics palette
$e82200 16.w Text palette (Palette block 0)
$e82220 240.w Sprite palette ('' 1-15)
$e82400 1.w R0 (Screen mode initialization)
$e82500 1.w R1 (Priority control)
$e82600 1.w R2 (Special priority/screen display) - Layers On/Off
$e84000 DMAC (HD63450)
$e86000 Memory controller privileged access settings (OHM/ASA)
$e88000 MFP (MC68901)
$e8a000 RTC (RP5C15)
$e8c000 Printer port
$e8e001 #1 Contrast
$e8e003 #2 Display/3D Shutter Glasses (Bit 0=Right Eye / Bit 1 = Left Eye)
$e8e005 #3 Color image unit (bit 4-0)
$e8e007 #4 Keyboard/NMI/dot clock
$e8e009 #5 ROM/DRAM Wait
$e8e00b #6 MPU Classification/Operation clock
$e8e00d #7 SRAM Write
$e8e00f #8 Unit power OFF
$E90001 FM Synthesizer (YM2151) - Register Address Write port
$E90003 FM Synthesizer (YM2151) - Data R/W port
$E92000 ADPCM (MSM6258V)
$E94000 Floppy disk controller (FDC) (uPD72065)
$E94005 Floppy drive monitor (IOSC)
$E96000 SASI
$E98000 ESCC (Z8530)
$E9A000 PPI (82C55)
$E9C000 I/O selector (IOSC)
$E9E000 I/O expansion area (Sharp reserved)
$EB0000 Sprite register (CYNTHIA)
$EB8000 Sprite VRAM
$EC0000 I/O expansion area (User)
$ed0072 2.b SX-Window environment flag (While in use with "SX")
$ed0074 1.b Standard double-click time / 10
$ed0075 1.b Mouse speed / 2
$ed0076 1.b Text palette hue (HSV)
$ed0077 1.b
$ed0078 1.b Brightness palette 0-3 5bit???
$ed007b 1.b Printer drive (PRTD) ID
$ed007c 1.b SRAM info version#, screen status storage, start screen storage
$ed007d 1.b Desktop background (PICT) ID
$ed007e 1.b Screen mode
$ed007f 17.b Reserved for system use (X68030)
$ed0090 1.b Standard cache status (bit=0: off 1:on)
$ed0091 1.b OPM music during startup (0: OFF -1: ON)
$ed0092 1.b 10MHz Proper wait value
$ed0093 1.b 16MHz ''
$ed0094 108.b Reserved for system use
$ed0100 768.b Head SRAM program address
$ed0400 15KB Head SRAMDISK address
$ed3fff End of SRAM
$ed4000 Backup (64KB)
$ee0000 Unused (128KB)
$f00000 CGROM(768KB)
$fc0000 SCSI IOCS / IPL(8KB)
$fe0000 ROM Debugger
$ff0000 IPL / ROM IOCS
</syntaxhighlight>

=== Setting up the Disk Image ===
To get up and running, you need to create a Human68k OS XDF disk image, which is a similar system to MS-DOS.

Add the following files to the disk image:
<syntaxhighlight lang="">
COMMAND.X
HUMAN.SYS
INTRO.R (This is the flat binary output for your intro)
</syntaxhighlight>
Optionally, like in DOS, you can add a AUTOEXEC.BAT that just launches your INTRO.R for auto-startup.

=== Setting the Supervisor ===
Like all 68000 systems, if you want to access registers, you need to set the supervisor mode first before doing anything else:
<syntaxhighlight lang="">
clr.l -(a7)
dc.w $ff20
</syntaxhighlight>

=== Video display ===
To get your video mode up and running, there are two call you need to make in a specific order

<syntaxhighlight lang="">
; Set CRT mode. Clears plane 0/1 on the text screen to set display mode.
; The graphics screen and sprite screen are put into silent mode without being cleared.
; The text palette is initialized.
moveq #10,d1
moveq #$10,d0
trap #15

; Enable graphics mode
; _G_CLR_ON Initializes the graphic screen and sets the display mode
; Clears the graphics screen and displays the palette. The page is set to 0.
move.w #$90,d0
trap #15

; Disable Text Cursor
moveq #$1f,d0
trap #15
</syntaxhighlight>

Here is a full list of all available graphics modes:
<syntaxhighlight lang="">
d1.w p.width resolution colors screens khz
===================================================
0 1024 512 x 512 16 1 31
1 V V V V 15
2 V 256 x 256 V V 31
3 V V V V 15
4 512 512 x 512 16 4 31
5 V V V V 15
6 V 256 x 256 V V 31
7 V V V V 15
8 V 512 x 512 256 2 31
9 V V V V 15
10 V 256 x 256 V V 31
11 V V V V 15
12 V 512 x 512 65536 1 31
13 V V V V 15
14 V 256 x 256 V V 31
15 V V V V 15
16 1024 768 x 512 16 1 31
17 V 1024 x 424 V V 24
18 V 1024 x 848 V V 24
19 V 640 x 480 V V 24
20 V 768 x 512 256 2 31
21 V 1024 x 848 V V 24
22 V 1024 x 424 V V 24
23 V 640 x 480 V V 24
24 V 768 x 512 65536 1 31
25 V 1024 x 848 V V 24
26 V 1024 x 424 V V 24
27 V 640 x 480 V V 24
</syntaxhighlight>

==== Vsync ====
<syntaxhighlight lang="">
waitVBlank:
move.w $e88000,d0
and.w #%00010000,d0 ;Wait for vblank to start
beq waitVBlank
waitVBlank2:
move.w $e88000,d0
and.w #%00010000,d0 ;Wait for Vblank to end
bne waitVBlank2
rts
</syntaxhighlight>

==== Double buffering ====
You can use the following IOCS routines to set the active drawing and screenpages for double buffering.
<syntaxhighlight lang="">
; APAGE: Graphic drawing page settings
move.w #$b1,d0
moveq #0,d1 ; set page 0..3
trap #15

; VPAGE: Graphic screen display page setting
move.w #$b2,d0
moveq #0,d1 ; set page 0..3
trap #15
</syntaxhighlight>

==== Clearing the screen ====
You can clear the active page using the WIPE IOCS routine ($b5)
<syntaxhighlight lang="">
move.w #$b5,d0
trap #15
</syntaxhighlight>

==== Plotting to screen ====
When accessing using GRAM directly, you can fill the GVRAM directly in word (64k colors), byte (8 bit palette) or 4-bit 16 color mode.
<syntaxhighlight lang="">
lea GVRAM,a0
move.w #256,d7
drawloop:
move.w (a0)+,d0
dbra d7,drawloop
</syntaxhighlight>
Since GVRAM buffer widths can differ from the resolution you are using, make sure to skip enough words at the end of each line to make up for the difference.

==== IOCS Drawing routines ====
Alternatively you could make use of the IOCS functions for drawing primitives using TRAP #15.
These are slow tom routines, compatible with all kinds of modes,
All these make use of a parameter buffer in A1 that you need to fill yourself with the correct information, for example for _PSET this would contain X,Y,COLOR like so:

<syntaxhighlight lang="">
lea params,a1
move.w d2,(a1) ; x-coord
move.w d3,2(a1) ; y-coord
move.w #255,4(a1) ; color
moveq #-($100-_PSET),d0
trap #15
</syntaxhighlight>

Here is a full list of other IOCS drawing routines you are able to use.
<syntaxhighlight lang="">
_PSET equ $b6
_POINT equ $b7
_LINE equ $b8
_BOX equ $b9
_FILL equ $ba
_CIRCLE equ $bb
_PAINT equ $bc
</syntaxhighlight>

=== Sound ===
The X68000 has a YM2151 FM Soundchip on board with 8 channels.
Each channel's sound can be built up with 4 different 'slots. There are a total of 32 slots that can be turned on or off when the sound is triggered. For more information, check out the YM2151 specs at [https://msxpro.com/datasheet.html]

Alternatively, there is also an option to output digital PCM sound.

=== Additional Resources ===
* [https://www.chibiakumas.com/68000/x68000.php Assembly programming for the X68000]
* [https://archive.org/details/X68000_488 X68000 Technical data book ]
* [https://msxpro.com/datasheet.html YM2151 Datasheet]
* [https://demozoo.org/productions/?platform=100 X68000 demoscene productions]
* [https://archive.org/details/cpsystem/page/202/mode/2up X68000 chapter in the book "The Book of CP-System"]
* [https://github.com/hitchhikr/xsdk X68000 Software Development Kit]

X68000

2026-02-12T07:19:03Z

Hitchhikr: fixed sdk link

== Sharp X68000 ==
The Sharp X68000 is a home computer created by Sharp Corporation. It was first released in 1987 and sold only in Japan.

The initial model has a 10 MHz Motorola 68000 CPU, 1 MB of RAM, and lacks a hard drive. The final model was released in 1993 with a 25 MHz Motorola 68030 CPU, 4 MB of RAM, and optional 80 MB SCSI hard drive. RAM in these systems is expandable to 12 MB, though most games and applications do not require more than 2 MB.

The X68000 has graphics hardware similar to arcade video games of the late-1980s, with custom coprocessors supporting scrolling, tiled backgrounds, and large numbers of sprites. Sound is supplied through multiple sound chips supporting 8 channels of FM synthesis and one channel of adaptive differential pulse-code modulation audio, which are mixed down to 2 analog stereo channels via a DAC chip. As such, video gaming was a major use of the X68000.

The X68000 runs an operating system called Human68k which was developed for Sharp by Hudson Soft. An MS-DOS-workalike, Human68k features English-based commands very similar to those in MS-DOS;

=== Setting up ===
* Assembler: VASM
* Tools: NDC to create an XDF Disk Image containing the production
* Emulator(s): http://retropc.net/pi/xm6/index.html , https://www.retrostic.com/emulators/sharp-x68000/winx68030, https://mijet.eludevisibility.org/XM6%20Pro-68k/XM6%20Pro-68k.html
* Hardware: Original X68000 or the new X68000Z emulation systems.

=== Memory map ===

<syntaxhighlight lang="">
address vector Function
$000000 $00 SSP after reset
$000004 $01 PC after reset
$000008 $02 Bus error
$00000c $03 Address error
$000010 $04 Unknown instruction
$000014 $05 Division by 0
$000018 $06 CHK instruction
$00001c $07 TRAPV instruction, FTRAPcc instruction
$000020 $08 Privilege violation
$000024 $09 Trace exception
$000028 $0a Unsupported instruction line 1010 emulator (SX call)
$00002c $0b ? line 1111 emulator (DOS call, floating point operation)
$000030 $0c Unused
$000034 $0d FPU Protocol violation exception handling
$000038 $0e Formatting error exception handling
$00003c $0f Uninitialized Interrupt
$000040 $10 Unused
$000044 $11 ?
$000048 $12 ?
$00004c $13 ?
$000050 $14 ?
$000054 $15 ?
$000058 $16 ?
$00005c $17 ?
$000060 $18 Spurious Interrupt
$000064 $19 Level 1 Interrupt (auto vector)
$000068 $1a ?
$00006c $1b ?
$000070 $1c ?
$000074 $1d ?
$000078 $1e ?
$00007c $1f ?
$000080 $20 trap #0
$000084 $21 ? #1
$000088 $22 ? #2
$00008c $23 ? #3
$000090 $24 ? #4
$000094 $25 ? #5
$000098 $26 ? #6
$00009c $27 ? #7
$0000a0 $28 ? #8 (reserved for system)
$0000a4 $29 ? #9 (OS debugger)
$0000a8 $2a ? #10 (reset & power off)
$0000ac $2b ? #11 (BREAK key)
$0000b0 $2c ? #12 (COPY key)
$0000b4 $2d ? #13 (CTRL+C)
$0000b8 $2e ? #14 (error processing)
$0000bc $2f ? #15 (IOCS call)
$0000c0 $30 FPU BSUN
$0000c0 $30 FPU BSUN
$0000c4 $31 ? INEX1,INEX2
$0000c8 $32 ? DZ
$0000cc $33 ? UNFL
$0000d0 $34 ? OPERR
$0000d4 $35 ? OVFL
$0000d8 $36 ? SNAN
$0000dc $37 ???
$0000dc $37 Unused
$0000e0 $38 MMU
$0000e4 $39 ?
$0000e8 $3a ?
$0000ec $3b Unused
$0000fc $3f Unused
$000100 $40 MFP RTC Alarm/1Hz
$000104 $41 MFP External power OFF
$000118 $42 MFP Front switch OFF
$00010c $43 MFP FM Audio source
$000110 $44 MFP Timer-D (Used with BG processing)
$000114 $45 MFP Timer-C (Mouse/cursor/FDD control, etc.)
$000118 $46 MFP V-DISP
$00011c $47 MFP RTC Clock
$000120 $48 MFP Timer-B
$000124 $49 MFP Key serial output error
$000128 $4a MFP Key serial output empty
$00012c $4b MFP Key serial input error
$000130 $4c MFP Key serial input
$000134 $4d MFP Timer-A
$000138 $4e MFP CRTC*IRQ
$00013c $4f MFP H-SYNC
$000140 $50 SCC(B) Transmission buffer empty
$000144 $51 SCC(B) ''
$000148 $52 SCC(B) External/status changes
$00014c $53 SCC(B) ''
$000150 $54 SCC(B) Incoming character validity (Mouse 1 byte input)
$000154 $55 SCC(B) ''
$000158 $56 SCC(B) Special Rx condition
$00015c $57 SCC(B) ''
$000160 $58 SCC(A) Transmission buffer empty
$000164 $59 SCC(A) ''
$000168 $5a SCC(A) External status changes
$00016c $5b SCC(A) ''
$000170 $5c SCC(A) Incoming character validity (RS-232C 1 byte input)
$000174 $5d SCC(A) ''
$000178 $5e SCC(A) Special Rx Condition
$00017c $5f SCC(A) ''
$000180 $60 I/O FDC status interruption
$000184 $61 I/O FDC insertion/discharge interruption
$000188 $62 I/O HDC status interruption
$00018c $63 I/O Printer ready interruption
$000190 $64 DMAC #0 End (FDD)
$000194 $65 DMAC #0 Error ('')
$000198 $66 DMAC #1 End (SASI)
$00019c $67 DMAC #1 Error ('')
$0001a0 $68 DMAC #2 End (IOCS _DMAMOVE,_DMAMOV_A,_DMAMOV_L)
$0001a4 $69 DMAC #2 Error ('')
$0001a8 $6a DMAC #3 End (ADPCM)
$0001ac $6b DMAC #3 Error ('')
$000200 $6c SPC SCSI interruption (Internal SCSI)
$000204 $6d Unused
$0003d4 $f5 Unused
$0003d8 $f6 SPC SCSI interruption (SCSI board)
$0003dc $f7 Unused
$0003fc $ff Unused
0x000000 RAM area
$c00000 Graphics Vram � Page 0
$c80000 Graphics Vram � Page 1 (256/16 color only)
$d00000 Graphics Vram � Page 2 (16 color only)
$d80000 Graphics Vram � Page 3 (16 color only)
$e00000 Text Vram � Bitplane 0
$e20000 Text Vram � Bitplane 1
$e40000 Text Vram � Bitplane 2
$e60000 Text Vram � Bitplane 3
$e80000 1.w R00 Horizontal total
$e80002 1.w R01 Horizontal synchronization end position timing
$e80004 1.w R02 Horizontal display start position
$e80006 1.w R03 Horizontal display end position
$e80008 1.w R04 Vertical total
$e8000a 1.w R05 Vertical synchronization end position timing
$e8000c 1.w R06 Vertical display start position
$e8000e 1.w R07 Vertical display end position
$e80010 1.w R08 External synchronization horizontal adjust: Horizontal position tuning
$e80012 1.w R09 Raster number: Used for raster interruption
$e80014 1.w R10 Text Screen X coordinate
$e80016 1.w R11 Text Screen Y coordinate
$e80018 1.w R12 Graphics screen Scroll X0
$e8001a 1.w R13 Graphics screen Scroll Y0
$e8001c 1.w R14 Graphics screen Scroll X1
$e8001e 1.w R15 Graphics screen Scroll Y1
$e80020 1.w R16 Graphics screen Scroll X2
$e80022 1.w R17 Graphics screen Scroll Y2
$e80024 1.w R18 Graphics screen Scroll X3
$e80026 1.w R19 Graphics screen Scroll Y3
$e80028 1.w R20 Memory mode/Display mode control
$e8002a 1.w R21 Simultaneous access/Raster copy/Quick clear plane select
$e8002c 1.w R22 Raster copy action: Raster number
$e8002e 1.w R23 Text screen access mask pattern
$e80481 1.b Active Image capture/Quick clear/Raster copy control
$e82000 256.w Graphics palette
$e82200 16.w Text palette (Palette block 0)
$e82220 240.w Sprite palette ('' 1-15)
$e82400 1.w R0 (Screen mode initialization)
$e82500 1.w R1 (Priority control)
$e82600 1.w R2 (Special priority/screen display) - Layers On/Off
$e84000 DMAC (HD63450)
$e86000 Memory controller privileged access settings (OHM/ASA)
$e88000 MFP (MC68901)
$e8a000 RTC (RP5C15)
$e8c000 Printer port
$e8e001 #1 Contrast
$e8e003 #2 Display/3D Shutter Glasses (Bit 0=Right Eye / Bit 1 = Left Eye)
$e8e005 #3 Color image unit (bit 4-0)
$e8e007 #4 Keyboard/NMI/dot clock
$e8e009 #5 ROM/DRAM Wait
$e8e00b #6 MPU Classification/Operation clock
$e8e00d #7 SRAM Write
$e8e00f #8 Unit power OFF
$E90001 FM Synthesizer (YM2151) - Register Address Write port
$E90003 FM Synthesizer (YM2151) - Data R/W port
$E92000 ADPCM (MSM6258V)
$E94000 Floppy disk controller (FDC) (uPD72065)
$E94005 Floppy drive monitor (IOSC)
$E96000 SASI
$E98000 ESCC (Z8530)
$E9A000 PPI (82C55)
$E9C000 I/O selector (IOSC)
$E9E000 I/O expansion area (Sharp reserved)
$EB0000 Sprite register (CYNTHIA)
$EB8000 Sprite VRAM
$EC0000 I/O expansion area (User)
$ed0072 2.b SX-Window environment flag (While in use with "SX")
$ed0074 1.b Standard double-click time / 10
$ed0075 1.b Mouse speed / 2
$ed0076 1.b Text palette hue (HSV)
$ed0077 1.b
$ed0078 1.b Brightness palette 0-3 5bit???
$ed007b 1.b Printer drive (PRTD) ID
$ed007c 1.b SRAM info version#, screen status storage, start screen storage
$ed007d 1.b Desktop background (PICT) ID
$ed007e 1.b Screen mode
$ed007f 17.b Reserved for system use (X68030)
$ed0090 1.b Standard cache status (bit=0: off 1:on)
$ed0091 1.b OPM music during startup (0: OFF -1: ON)
$ed0092 1.b 10MHz Proper wait value
$ed0093 1.b 16MHz ''
$ed0094 108.b Reserved for system use
$ed0100 768.b Head SRAM program address
$ed0400 15KB Head SRAMDISK address
$ed3fff End of SRAM
$ed4000 Backup (64KB)
$ee0000 Unused (128KB)
$f00000 CGROM(768KB)
$fc0000 SCSI IOCS / IPL(8KB)
$fe0000 ROM Debugger
$ff0000 IPL / ROM IOCS
</syntaxhighlight>

=== Setting up the Disk Image ===
To get up and running, you need to create a Human68k OS XDF disk image, which is a similar system to MS-DOS.

Add the following files to the disk image:
<syntaxhighlight lang="">
COMMAND.X
HUMAN.SYS
INTRO.R (This is the flat binary output for your intro)
</syntaxhighlight>
Optionally, like in DOS, you can add a AUTOEXEC.BAT that just launches your INTRO.R for auto-startup.

=== Setting the Supervisor ===
Like all 68000 systems, if you want to access registers, you need to set the supervisor mode first before doing anything else:
<syntaxhighlight lang="">
clr.l -(a7)
dc.w $ff20
</syntaxhighlight>

=== Video display ===
To get your video mode up and running, there are two call you need to make in a specific order

<syntaxhighlight lang="">
; Set CRT mode. Clears plane 0/1 on the text screen to set display mode.
; The graphics screen and sprite screen are put into silent mode without being cleared.
; The text palette is initialized.
moveq #10,d1
moveq #$10,d0
trap #15

; Enable graphics mode
; _G_CLR_ON Initializes the graphic screen and sets the display mode
; Clears the graphics screen and displays the palette. The page is set to 0.
move.w #$90,d0
trap #15

; Disable Text Cursor
moveq #$1f,d0
trap #15
</syntaxhighlight>

Here is a full list of all available graphics modes:
<syntaxhighlight lang="">
d1.w p.width resolution colors screens khz
===================================================
0 1024 512 x 512 16 1 31
1 V V V V 15
2 V 256 x 256 V V 31
3 V V V V 15
4 512 512 x 512 16 4 31
5 V V V V 15
6 V 256 x 256 V V 31
7 V V V V 15
8 V 512 x 512 256 2 31
9 V V V V 15
10 V 256 x 256 V V 31
11 V V V V 15
12 V 512 x 512 65536 1 31
13 V V V V 15
14 V 256 x 256 V V 31
15 V V V V 15
16 1024 768 x 512 16 1 31
17 V 1024 x 424 V V 24
18 V 1024 x 848 V V 24
19 V 640 x 480 V V 24
20 V 768 x 512 256 2 31
21 V 1024 x 848 V V 24
22 V 1024 x 424 V V 24
23 V 640 x 480 V V 24
24 V 768 x 512 65536 1 31
25 V 1024 x 848 V V 24
26 V 1024 x 424 V V 24
27 V 640 x 480 V V 24
</syntaxhighlight>

==== Vsync ====
<syntaxhighlight lang="">
waitVBlank:
move.w $e88000,d0
and.w #%00010000,d0 ;Wait for vblank to start
beq waitVBlank
waitVBlank2:
move.w $e88000,d0
and.w #%00010000,d0 ;Wait for Vblank to end
bne waitVBlank2
rts
</syntaxhighlight>

==== Double buffering ====
You can use the following IOCS routines to set the active drawing and screenpages for double buffering.
<syntaxhighlight lang="">
; APAGE: Graphic drawing page settings
move.w #$b1,d0
moveq #0,d1 ; set page 0..3
trap #15

; VPAGE: Graphic screen display page setting
move.w #$b2,d0
moveq #0,d1 ; set page 0..3
trap #15
</syntaxhighlight>

==== Clearing the screen ====
You can clear the active page using the WIPE IOCS routine ($b5)
<syntaxhighlight lang="">
move.w #$b5,d0
trap #15
</syntaxhighlight>

==== Plotting to screen ====
When accessing using GRAM directly, you can fill the GVRAM directly in word (64k colors), byte (8 bit palette) or 4-bit 16 color mode.
<syntaxhighlight lang="">
lea GVRAM,a0
move.w #256,d7
drawloop:
move.w (a0)+,d0
dbra d7,drawloop
</syntaxhighlight>
Since GVRAM buffer widths can differ from the resolution you are using, make sure to skip enough words at the end of each line to make up for the difference.

==== IOCS Drawing routines ====
Alternatively you could make use of the IOCS functions for drawing primitives using TRAP #15.
These are slow tom routines, compatible with all kinds of modes,
All these make use of a parameter buffer in A1 that you need to fill yourself with the correct information, for example for _PSET this would contain X,Y,COLOR like so:

<syntaxhighlight lang="">
lea params,a1
move.w d2,(a1) ; x-coord
move.w d3,2(a1) ; y-coord
move.w #255,4(a1) ; color
move.l #_PSET,d0
trap #15
</syntaxhighlight>

Here is a full list of other IOCS drawing routines you are able to use.
<syntaxhighlight lang="">
_PSET equ $b6
_POINT equ $b7
_LINE equ $b8
_BOX equ $b9
_FILL equ $ba
_CIRCLE equ $bb
_PAINT equ $bc
</syntaxhighlight>

=== Sound ===
The X68000 has a YM2151 FM Soundchip on board with 8 channels.
Each channel's sound can be built up with 4 different 'slots. There are a total of 32 slots that can be turned on or off when the sound is triggered. For more information, check out the YM2151 specs at [https://msxpro.com/datasheet.html]

Alternatively, there is also an option to output digital PCM sound.

=== Additional Resources ===
* [https://www.chibiakumas.com/68000/x68000.php Assembly programming for the X68000]
* [https://archive.org/details/X68000_488 X68000 Technical data book ]
* [https://msxpro.com/datasheet.html YM2151 Datasheet]
* [https://demozoo.org/productions/?platform=100 X68000 demoscene productions]
* [https://archive.org/details/cpsystem/page/202/mode/2up X68000 chapter in the book "The Book of CP-System"]
* [https://github.com/hitchhikr/xsdk X68000 Software Development Kit]

Commodore Amiga

2026-02-12T06:56:37Z

Hitchhikr: /* Sound */

== Commodore Amiga ==
The Commodore Amiga system consists of the M68k system with custom hardware for graphics and sound.

=== Setting up ===

* Assembler: VASM
* Emulator(s): Linux: fs-uae, Windows: WinUAE

Compile source to Amiga Kickstart1.x executable:

<syntaxhighlight lang="">
vasm -kick1hunks -Fhunkexe -o example -nosym
</syntaxhighlight>

=== Amiga executable format ===
Commodore Amiga executables consist of a 32 byte header, as well as a 4 byte footer. Here's an example where deadc0de is the only code data. 0000 03f2 marks the end of the block.
<syntaxhighlight lang="">
00000000: 0000 03f3 0000 0000 0000 0001 0000 0000
00000010: 0000 0000 0000 0001 0000 03e9 0000 0001
00000020: dead c0de 0000 03f2
</syntaxhighlight>

=== Memory Map ===
Here is the amiga memory map
<gallery>
Amiga_memorymap.png
</gallery>

=== Video display ===
The Amiga OCS uses an interleaved planar memory layout to represent its various paletted display modes.

==== Getting something on screen ====
One of the shortest ways to get you started with getting anything on screen at all, is to initialize and use the intuition graphics library routines.
These are relatively easy to setup and allow you to plot pixels, circles, rects and even polygons.
However, as can be expected these routines are extremely slow in execution.

<syntaxhighlight lang="">
incdir "include"
include "graphics/graphics_lib.i"
include "intuition/screens.i"

move.l $170(a2),a6 ; intuitionbase from globvec
move.l ib_ActiveScreen(a6),a5 ; a5 = activeScreen (640x240 on most systems)
move.l $4.w,a6 ; execbase
move.l 156(a6),a6 ; graphics.library

; clear screen
lea sc_RastPort(a5),a1
jsr _LVOClearScreen(a6)

frameloop:
move.w #240-1,d7 ; y
yLoop:
move.w #640-1,d6 ; x
xLoop:
; Set Pixel/Pen Color (d0 = color)
move d6,d0 ; d0=x
eor d7,d0 ; d0=x^y
lsr #3,d0 ; d0>>=3
jsr _LVOSetAPen(a6)

; Write Pixel (d0=x, d1=y)
move d6,d0
move d7,d1
jsr _LVOWritePixel(a6)
dbra d6,xLoop
dbra d7,yLoop

bra frameloop
</syntaxhighlight>

==== Copperlist ====
Another way to start drawing things on screen is to setup a (minimal) copperlist with commands for one or more planes, which can be manipulated indiviually

Copper list format:
<syntaxhighlight lang="">
To be added
</syntaxhighlight>

As it happens, you can also insert color definition into the copperlist.

==== Planes ====
Every plane contains one bit of a pixel's colour index value. The bits of the binary representation of a colour index like %1010 (% Bit3,Bit2,Bit1,Bit0) will end up in 6 different planes (bits most significant to least significant aka left to right): Plane4 Plane3 Plane2 Plane1.

So basicly Plane1 contains all of the Bit0s of all pixels, Plane2 all Bit1s, Plane3 all Bit2s and Plane4 all Bit3s.

The first pixel on a plane is described by the leftmost (aka most significant) bit in a word, the second one by the second-leftmost etc. - just like this %0123456789abcdef with 0-f=pixels 1-16. %1000000000000000=$8000=pixel 1 in a plane word set. The 16th pixel will use the leftmost bit of the next word in this plane. etc.

==== Drawing pixels ====
Here are some examples for drawing pixels in 1 or more bitplanes:

1-bpp pixel plot
<syntaxhighlight lang="">
To be added
</syntaxhighlight>

2-bpp pixel plot
<syntaxhighlight lang="">
To be added
</syntaxhighlight>

==== Setting a palette====
The Amiga OCS uses index values into a palette of colours. Palette format is a word per index with 3 nibbles for 4-bit RGB (e.g. $00f for blue). Here is some code that will help you setup an entire palette at once using the intuition graphics routine.

<syntaxhighlight lang="">
lea sc_ViewPort(a5),a0
lea paldata(pc),a1
moveq #16,d0
jsr _LVOLoadRGB4(a6)

; Palette data
paldata:
dc.w $000,$100,$200,$311,$422,$533,$644,$755
dc.w $575,$464,$353,$242,$131,$020,$010,$000
</syntaxhighlight>

Alternatively you can set individual palette entries either by using a graphics function or using the copperlist for setting initial colors

=== Sound ===
To Paula chip (registers $DFF0A0-$DFF0DA) is able to output 8-bit PCM through a maximum of 4 channels.
Since the chip's dma is fed every horizontal scanline, you need to share cycles between the soundchip and other processes, impacting the maximum frequency or channels you can use at any given time.

The maximum audio buffer length is 65535 words (or about 128k of samples)

==== Make some noise ====
So, here is a bit of sound code that outputs a single channel sound.
<syntaxhighlight lang="">
move.l #pcmdata,$dff0a0 ; data to play (must be located in chipmem)
move.l #32<<16+(252*8),$dff0a4 ; length, period
move.w #64,$dff0a8 ; set volume
move.w #$8001,$dff096 ; enable audio channel 0
</syntaxhighlight>

=== Additional Resources ===
* [https://amycoders.org/ AmyCoders]
* [https://archive.org/details/Amiga_Hardware_Reference_Manual_1985_Commodore Amiga Harware Reference Manual from Commodore (scans on Archive.org)]
* [http://amigadev.elowar.com/read/ADCD_2.1/Hardware_Manual_guide/node0000.html Hardware Manual Guide]
* [https://wiki.amigaos.net/wiki/Graphics_Primitives/ Overview of Graphics primitives drawing]
* [https://www.markwrobel.dk/project/amigamachinecode/ Learning Amiga machine code]
* [https://heckmeck.de/demoscene/ Amiga coding Blogposts by Losso]
* [http://www.coppershade.org/articles/Code/Articles/ Coppershade articles]
* [http://amiga-dev.wikidot.com/file-format:hunk#toc7 Amiga Header information]
* [http://amiga-dev.wikidot.com/information:hardware Amiga Hardware registers overview]
* [https://github-wiki-see.page/m/echolevel/open-amiga-sampler/wiki/Appendix-A%3A-Sample-rates-deep-dive Paula Sample rates]

Commodore Amiga

2026-02-12T06:56:15Z

Hitchhikr: /* Sound */

== Commodore Amiga ==
The Commodore Amiga system consists of the M68k system with custom hardware for graphics and sound.

=== Setting up ===

* Assembler: VASM
* Emulator(s): Linux: fs-uae, Windows: WinUAE

Compile source to Amiga Kickstart1.x executable:

<syntaxhighlight lang="">
vasm -kick1hunks -Fhunkexe -o example -nosym
</syntaxhighlight>

=== Amiga executable format ===
Commodore Amiga executables consist of a 32 byte header, as well as a 4 byte footer. Here's an example where deadc0de is the only code data. 0000 03f2 marks the end of the block.
<syntaxhighlight lang="">
00000000: 0000 03f3 0000 0000 0000 0001 0000 0000
00000010: 0000 0000 0000 0001 0000 03e9 0000 0001
00000020: dead c0de 0000 03f2
</syntaxhighlight>

=== Memory Map ===
Here is the amiga memory map
<gallery>
Amiga_memorymap.png
</gallery>

=== Video display ===
The Amiga OCS uses an interleaved planar memory layout to represent its various paletted display modes.

==== Getting something on screen ====
One of the shortest ways to get you started with getting anything on screen at all, is to initialize and use the intuition graphics library routines.
These are relatively easy to setup and allow you to plot pixels, circles, rects and even polygons.
However, as can be expected these routines are extremely slow in execution.

<syntaxhighlight lang="">
incdir "include"
include "graphics/graphics_lib.i"
include "intuition/screens.i"

move.l $170(a2),a6 ; intuitionbase from globvec
move.l ib_ActiveScreen(a6),a5 ; a5 = activeScreen (640x240 on most systems)
move.l $4.w,a6 ; execbase
move.l 156(a6),a6 ; graphics.library

; clear screen
lea sc_RastPort(a5),a1
jsr _LVOClearScreen(a6)

frameloop:
move.w #240-1,d7 ; y
yLoop:
move.w #640-1,d6 ; x
xLoop:
; Set Pixel/Pen Color (d0 = color)
move d6,d0 ; d0=x
eor d7,d0 ; d0=x^y
lsr #3,d0 ; d0>>=3
jsr _LVOSetAPen(a6)

; Write Pixel (d0=x, d1=y)
move d6,d0
move d7,d1
jsr _LVOWritePixel(a6)
dbra d6,xLoop
dbra d7,yLoop

bra frameloop
</syntaxhighlight>

==== Copperlist ====
Another way to start drawing things on screen is to setup a (minimal) copperlist with commands for one or more planes, which can be manipulated indiviually

Copper list format:
<syntaxhighlight lang="">
To be added
</syntaxhighlight>

As it happens, you can also insert color definition into the copperlist.

==== Planes ====
Every plane contains one bit of a pixel's colour index value. The bits of the binary representation of a colour index like %1010 (% Bit3,Bit2,Bit1,Bit0) will end up in 6 different planes (bits most significant to least significant aka left to right): Plane4 Plane3 Plane2 Plane1.

So basicly Plane1 contains all of the Bit0s of all pixels, Plane2 all Bit1s, Plane3 all Bit2s and Plane4 all Bit3s.

The first pixel on a plane is described by the leftmost (aka most significant) bit in a word, the second one by the second-leftmost etc. - just like this %0123456789abcdef with 0-f=pixels 1-16. %1000000000000000=$8000=pixel 1 in a plane word set. The 16th pixel will use the leftmost bit of the next word in this plane. etc.

==== Drawing pixels ====
Here are some examples for drawing pixels in 1 or more bitplanes:

1-bpp pixel plot
<syntaxhighlight lang="">
To be added
</syntaxhighlight>

2-bpp pixel plot
<syntaxhighlight lang="">
To be added
</syntaxhighlight>

==== Setting a palette====
The Amiga OCS uses index values into a palette of colours. Palette format is a word per index with 3 nibbles for 4-bit RGB (e.g. $00f for blue). Here is some code that will help you setup an entire palette at once using the intuition graphics routine.

<syntaxhighlight lang="">
lea sc_ViewPort(a5),a0
lea paldata(pc),a1
moveq #16,d0
jsr _LVOLoadRGB4(a6)

; Palette data
paldata:
dc.w $000,$100,$200,$311,$422,$533,$644,$755
dc.w $575,$464,$353,$242,$131,$020,$010,$000
</syntaxhighlight>

Alternatively you can set individual palette entries either by using a graphics function or using the copperlist for setting initial colors

=== Sound ===
To Paula chip (registers DFF0A0-DFF0DA) is able to output 8-bit PCM through a maximum of 4 channels.
Since the chip's dma is fed every horizontal scanline, you need to share cycles between the soundchip and other processes, impacting the maximum frequency or channels you can use at any given time.

The maximum audio buffer length is 65535 words (or about 128k of samples)

==== Make some noise ====
So, here is a bit of sound code that outputs a single channel sound.
<syntaxhighlight lang="">
move.l #pcmdata,$dff0a0 ; data to play (must be located in chipmem)
move.l #32<<16+(252*8),$dff0a4 ; length, period
move.w #64,$dff0a8 ; set volume
move.w #$8001,$dff096 ; enable audio channel 0
</syntaxhighlight>

=== Additional Resources ===
* [https://amycoders.org/ AmyCoders]
* [https://archive.org/details/Amiga_Hardware_Reference_Manual_1985_Commodore Amiga Harware Reference Manual from Commodore (scans on Archive.org)]
* [http://amigadev.elowar.com/read/ADCD_2.1/Hardware_Manual_guide/node0000.html Hardware Manual Guide]
* [https://wiki.amigaos.net/wiki/Graphics_Primitives/ Overview of Graphics primitives drawing]
* [https://www.markwrobel.dk/project/amigamachinecode/ Learning Amiga machine code]
* [https://heckmeck.de/demoscene/ Amiga coding Blogposts by Losso]
* [http://www.coppershade.org/articles/Code/Articles/ Coppershade articles]
* [http://amiga-dev.wikidot.com/file-format:hunk#toc7 Amiga Header information]
* [http://amiga-dev.wikidot.com/information:hardware Amiga Hardware registers overview]
* [https://github-wiki-see.page/m/echolevel/open-amiga-sampler/wiki/Appendix-A%3A-Sample-rates-deep-dive Paula Sample rates]

X68000

2025-06-09T17:27:45Z

Hitchhikr: Added link to XM6 PRO emulator

X68000

2025-06-09T17:18:15Z

Hitchhikr:

X68000

2025-06-09T17:17:08Z

Hitchhikr: fixed demozoo link