Difference between revisions of "Game of Life 32b"
From SizeCoding
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==Original version : 65 bytes== | ==Original version : 65 bytes== | ||
| − | We'll start with the old 65 bytes version and bring it down to 32 bytes. | + | We'll start with the old 65 bytes version and bring it down to 32 bytes.<br /> |
| + | |||
| + | </br> | ||
| + | It will help to understand what the core algorithm does, before optimizing it. I will not go into the details of random number generation and key handling since these parts are removed in the final version anyway. The core routine computes the [https://en.wikipedia.org/wiki/Conway%27s_Game_of_Life#Rules "normal" game of life rules, but with a twist. Instead of regarding only neighbour cells inside a 3x3 neighbourhood , ALL cells are taken into consideration, and the rules are reinterpreted as: | ||
| + | |||
| + | * If the number of cells is 3, the center cell will be alive. | ||
| + | * If the number of cells is 4, the center cell keeps its state. | ||
| + | * Otherwise, the cell dies (or stays dead). | ||
| + | |||
<syntaxhighlight lang="nasm"> | <syntaxhighlight lang="nasm"> | ||
| Line 74: | Line 82: | ||
End Start | End Start | ||
</syntaxhighlight> | </syntaxhighlight> | ||
| + | |||
==Remove key handler and RNG : 44 bytes== | ==Remove key handler and RNG : 44 bytes== | ||
<syntaxhighlight lang="nasm"> | <syntaxhighlight lang="nasm"> | ||
Revision as of 08:32, 30 April 2020
This writeup is still in the works! Come back later to get information on all the mean tricks ;) Meanwhile you can download and comment the intro.
Contents
Original version : 65 bytes
We'll start with the old 65 bytes version and bring it down to 32 bytes.
</br> It will help to understand what the core algorithm does, before optimizing it. I will not go into the details of random number generation and key handling since these parts are removed in the final version anyway. The core routine computes the [https://en.wikipedia.org/wiki/Conway%27s_Game_of_Life#Rules "normal" game of life rules, but with a twist. Instead of regarding only neighbour cells inside a 3x3 neighbourhood , ALL cells are taken into consideration, and the rules are reinterpreted as:
- If the number of cells is 3, the center cell will be alive.
- If the number of cells is 4, the center cell keeps its state.
- Otherwise, the cell dies (or stays dead).
; http://read.pudn.com/downloads208/sourcecode/asm/981812/LIFE65.ASM__.htm
; Life simulator, 72 bytes - Vladislav Kaipetsky and Tenie Remmel
; 65 bytes - Mark Andreas
; If no args, regs on startup are:
; AX = BX = 0000h
; SI = IP = 0100h
; DI = SP = FFFEh
IDEAL
MODEL TINY
P386
CODESEG
ORG 100h
Start: int 1ah ; ah=00: cx=hours, dx=tic counter
mov al,13h ; Set mode 13h
int 10h
xchg dx,ax
push 09000h ; DS = last 64K segment
pop ds
push 0A000h ; ES = video memory
pop es
; BX is already zero
RandLoop:
rol ax,1 ; Generate random number
adc [bx],al
dec bx
jnz RandLoop
; BX will not be equal to 3 the first time this loop is executed, but
; it will be for all other times. As SI = 0100h and DI = FFFEh on
; startup, SI - DI will be equal to 258.
LifeLoop:
xchg cx,ax
AccLoop:
add cl,[di+bx-64] ; Add in this column
add cl,[si+bx-2]
add cl,[si+bx+318]
dec bx ; Loop back
jnz AccLoop
mov al,[si] ; Get center cell, set pixel
stosb
stc ; 3 = birth, 4 = stay (tricky):
rcr al,cl ; 1.00?0000x --> 0.0x100?00 (rcr 3)
and al,20h ; ^carry | ^
; +---> 0.00x100?0 (rcr 4)
or [si-1],al ; Add in new cell ^
shr [byte di-65],5 ; Shift previous value
mov bl,3 ; 3 iterations in AccLoop
inc si ; Loop while not zero
jnz LifeLoop
mov ah,1 ; Check for key
int 16h
jz LifeLoop ; Loop if no key
xchg ax,bx ; Set text mode
int 10h
ret ; Return
End Start
Remove key handler and RNG : 44 bytes
Start:
mov al,93h ; Set mode 13h
int 10h
push 09000h ; DS = last 64K segment
pop ds
push 0A000h ; ES = video memory
pop es
; BX is already zero
LifeLoop:
xchg cx,ax
AccLoop:
add cl,[di+bx-64] ; Add in this column
add cl,[si+bx-2]
add cl,[si+bx+318]
dec bx ; Loop back
jnz AccLoop
;mov al,[si] ; Get center cell, set pixel
lodsb
stosb
stc ; 3 = birth, 4 = stay (tricky):
rcr al,cl ; 1.00?0000x --> 0.0x100?00 (rcr 3)
and al,20h ; ^carry | ^
; +---> 0.00x100?0 (rcr 4)
or [si-1],al ; Add in new cell ^
shr [byte di-65],5 ; Shift previous value
mov bl,3 ; 3 iterations in AccLoop
; inc si ; Loop while not zero
jmp short LifeLoop
Switching to Textmode : 39 bytes
push 0xb800
pop ds
LifeLoop:
stc ; 3 = birth, 4 = stay (tricky):
rcr al,cl ; 1.00?0000x --> 0.0x100?00 (rcr 3)
and al,20h ; ^carry | ^
or [si-2],al ; Add in new cell ^
shr byte [si-160-6],5 ; Shift previous value
mov bl,6
xchg cx,ax
AccLoop: add cl,[si+bx-160-4] ; Add in this column
add cl,[si+bx-4]
add cl,[si+bx+160-4]
dec bx ; Loop back
dec bx ; Loop back
jnz AccLoop
lodsw
jmp LifeLoop
TODO
