Corewars – Brainf*ck

I’ve implemented a Brainfuck interpreter!

Yes, you heard it right, Brainfuck (BF).
BF is an esoteric programming language. More information on BF can be found here.

The language itself is pretty simple, and most of it was implemented rather quickly in Redcode. The only big problem was navigating back to the correct closing brackets in a loop. This is now solved by counting the amount of open/close brackets in between.

So here is the code:

;----------------------------------------------
;redcode-94nop
;name Brainfuck Interpreter (v0.3)
;author Roy van Rijn
;strategy Brainfuck Interpreter with self-reproduction program (a quine)
;strategy It takes 7244366 cycles (runs slow!)
;assert 1 

LT      equ     60 ;<
GT      equ     62 ;>
INC     equ     43 ;+
DEC     equ     45 ;-
OUT     equ     46 ;.
IN      equ     44 ;,
OP      equ     91 ;[
CL      equ     93 ;] 

lt      equ     dat LT  , cLT-START
gt      equ     dat GT  , cGT-START
inc     equ     dat INC , cINC-START
dec     equ     dat DEC , cDEC-START
out     equ     dat OUT , cOUT-START
in      equ     dat IN  , cIN-START
op      equ     dat OP  , cOP-START
cl      equ     dat CL  , cCL-START 

;Use switch-table
cINC    add     #2              , @PTR          ;add 2 min 1
cDEC    sub     #1              , @PTR          ;min 1 

START   mov.b   }PTR            , #0
       jmp     @-1 

cLT     jmp     START           , <PTR
cGT     jmp     START           , >PTR 

cOUT    mov.b   @PTR            , <6000         ;sts.b  @PTR
       jmp     START
cIN     mov.b   }INPUT          , @PTR          ;now using INPUT-table instead or streams
       jmp     START 

;Optimize by using a stack? remembering the layer+position?
cOP     jmn     START           , @PTR
opCheck sne.ab  *PTR            , #OP
       add     #1              , CNT1 ;Count nested brackets
       seq.ab  }PTR            , #CL
       jmp     opCheck
CNT1    djn.b   opCheck         , #1
       jmp     START           , >CNT1 

cCL     jmz     START           , @PTR
       nop     {PTR            , >CNT2
clCheck sne.ab  {PTR            , #CL
       add     #1              , CNT2 ;Count nested brackets
       seq.ab  *PTR            , #OP
       jmp     clCheck
CNT2    djn.b   clCheck         , #0
       jmp     START 

;Used to mimic keypresses (when not using exmars_streams)
INPUT   dat     0               , -1 

PROGRAM 

;Brainfuck Quine, unsure who wrote the original.... (not me anyway!) 

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EOF     dat     0               , -10           ; Halt
PTR     dat     #PROGRAM        , #1            ; A: Execution pointer, B: Data pointer 

end START 

;Translated Brainfuck "Hello World" program
;
;The original is:
;++++++++++[>+++++++>++++++++++>+++>+<<<<-]
;>++.>+.+++++++..+++.>++.<<+++++++++++++++.>
;.+++.------.--------.>+.>. 

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EOF     dat     0               , -10           ; Halt
PTR     dat     #PROGRAM        , #1            ; A: Execution pointer, B: Data pointer 

end START

Category: Corewar | Tags: brainfuck, esoteric, Quine | Comment (1)