Difference between revisions of "6502"

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== Introduction ==
 
== Introduction ==
 
Wanting to start sizecoding on a 6502 platform in this day and age can be tough.  
 
Wanting to start sizecoding on a 6502 platform in this day and age can be tough.  
 +
 +
[[File:6502.jpg|thumb]]
  
 
So here is a bit of help to get you started:
 
So here is a bit of help to get you started:
  
 
=== The 6502 processor  ===
 
=== The 6502 processor  ===
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The 6502 processor can be seen as the 8bit micro ARM chip.  
+
The 6502 processor can be seen as the 8-bit micro ARM chip.  
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It has only has 3 registers (Accumilator, IX and IY registers) and only a handful of instructions to work with.
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It has only has 3 registers (Accumulator, X and Y registers) and a handful of instructions to work with.
  
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=== Registers ===
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=== Adressing modes ===
 
To be added.
 
To be added.
  
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When using the 6502 for sizecoding, you'll mostly be working from zeropage
 
When using the 6502 for sizecoding, you'll mostly be working from zeropage
  
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== Atari 8bit family ==
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== 6502 Based Platforms ==
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The Atari XE/XL systems consists of the 6502 with custom hardware for graphics and sound.
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*'''[[Atari 8Bit]]''' - Atari 8-Bit Family (Atari XL/XE, etc.)
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*'''[[Apple II]]''' - Apple II(e)
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=== Setting up ===
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*'''[[Commodore 64]]''' - Commodore 64
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Setting up your development platform for the Atari 8bit systems is quite easy, first get the following tools:
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*'''[[BBC Micro]]''' - Acorn BBC Micro/Master/Electron.
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*'''[[Atari Lynx]]''' - Atari Lynx Handheld
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* Assembler: MADS Assembler - This assembler has nice macros for creating Binaries and SNA snapshot files out of the box. You can download it at https://mads.atari8.info/
 
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* Emulator(s): I Found Altirra to work best for my usecase. Make sure to use the original Rev2 rom for best compatibility.
 
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=== Video display ===
 
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Video display on the Atari 8bit systems use the TIA chip, it has the following video modes:
 
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−
To be added soon.
 
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==== Getting something on screen ====
 
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To be added soon.
 
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−
 
 
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=== Sound ===
 
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The Atari 8bit systems use the Pokey chip to generate sound.
 
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To be added soon.
 
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==== Make some noise ====
 
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To be added soon.
 
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=== Additional Resources ===
 
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Sizecoding resource for the Atari 8bit are sparse
 
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* Fready's github (link to be added)
 
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== Atari Lynx ==
 
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The Atari Lynx consists of the 6502 with custom hardware for graphics and sound.
 
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=== Setting up ===
 
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Setting up your development platform for the Atari Lynx:
 
−
 
 
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* Assembler: -
 
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* Emulator(s): -
 
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=== Video diplay ===
 
−
To be added soon.
 
−
 
 
−
=== Getting something on screen ===
 
−
To be added soon.
 
−
 
 
−
 
 
−
=== Sound ===
 
−
To be added soon.
 
−
 
 
−
=== Make some noise ===
 
−
To be added soon.
 
−
 
 
−
 
 
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== Commodore 64 ==
 
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The Commodore systems consists of the 6502 with custom hardware for graphics and sound.
 
−
 
 
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=== Setting up ===
 
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Setting up your development platform for the Commodore systems is quite easy, first get the following tools:
 
−
 
 
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* Assembler: To be added
 
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* Emulator(s): VICE is the way to go
 
−
 
 
−
=== Video diplay ===
 
−
Video display on the Commodore, it has the following video modes:
 
−
 
 
−
To be added soon.
 
−
 
 
−
=== Getting something on screen ===
 
−
To be added soon.
 
−
 
 
  
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=== Sound ===
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== Generic 6502 sinus table generator ==
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The Commodore 64 uses the famous SID chip to generate sound.
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<syntaxhighlight lang="">
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To be added soon.
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ldx #0
 +
ldy #$3f
 +
make_sine:
 +
value_lo
 +
lda #0
 +
clc
 +
delta_lo
 +
adc #0
 +
sta value_lo+1
 +
value_hi
 +
lda #0
 +
delta_hi
 +
adc #0
 +
sta value_hi+1
 +
 +
sta sintab+$c0,x
 +
sta sintab+$80,y
 +
eor #$7f
 +
sta sintab+$40,x
 +
sta sintab+$00,y
 +
 +
lda delta_lo+1
 +
adc #8
 +
sta delta_lo+1
 +
bcc nothing
 +
inc delta_hi+1
 +
nothing
 +
inx
 +
dey
 +
bpl make_sine
 +
</syntaxhighlight>
  
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=== Make some noise ===
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=== General 6502 Resources ===
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To be added soon.
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* 6502.org http://www.6502.org/
 +
* 6502 instruction reference http://www.6502.org/tutorials/6502opcodes.html
 +
* 6502 books http://retro.hansotten.nl/6502-sbc/
 +
* 6502 Assembler tutorial https://dwheeler.com/6502/oneelkruns/asm1step.html
 +
* Easy 6502 code tester https://skilldrick.github.io/easy6502/
 +
* Synthetic instructions https://wiki.nesdev.com/w/index.php/Synthetic_instructions#8-bit_rotate

Latest revision as of 12:55, 8 April 2024

Introduction

Wanting to start sizecoding on a 6502 platform in this day and age can be tough.

6502.jpg

So here is a bit of help to get you started:

The 6502 processor

The 6502 processor can be seen as the 8-bit micro ARM chip. It has only has 3 registers (Accumulator, X and Y registers) and a handful of instructions to work with.

Adressing modes

To be added.

Zero page

When using the 6502 for sizecoding, you'll mostly be working from zeropage

6502 Based Platforms

Generic 6502 sinus table generator

	ldx #0
	ldy #$3f
make_sine:
value_lo
			lda #0
			clc
delta_lo
			adc #0
			sta value_lo+1
value_hi
			lda #0
delta_hi
			adc #0
			sta value_hi+1
 
			sta sintab+$c0,x
			sta sintab+$80,y
			eor #$7f
			sta sintab+$40,x
			sta sintab+$00,y
 
			lda delta_lo+1
			adc #8
			sta delta_lo+1
			bcc nothing
			inc delta_hi+1
nothing
			inx
			dey
			bpl make_sine

General 6502 Resources

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