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chip8

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This commit is contained in:
Matthew Butterick 2016-05-26 23:39:50 -07:00
parent 918efa4609
commit 24317fc860
1 changed files with 35 additions and 16 deletions
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51
beautiful-racket/br/demo/chip8.rkt
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@ -3,7 +3,7 @@
; http://devernay.free.fr/hacks/chip8/C8TECH10.HTM
; http://mattmik.com/files/chip8/mastering/chip8.html
(define (explode-bytes val)
(define (split-bytes val)
(cond
[(zero? val) (list 0)]
[else
@ -17,21 +17,21 @@
(module+ test
(require rackunit)
(check-equal? (explode-bytes #x2B45) (list #x2 #xB #x4 #x5))
(check-equal? (explode-bytes #xCD) (list #xC #xD))
(check-equal? (explode-bytes #xA) (list #xA))
(check-equal? (explode-bytes #x0) (list #x0)))
(check-equal? (split-bytes #x2B45) (list #x2 #xB #x4 #x5))
(check-equal? (split-bytes #xCD) (list #xC #xD))
(check-equal? (split-bytes #xA) (list #xA))
(check-equal? (split-bytes #x0) (list #x0)))
(define (glue-bytes bytes)
(define (join-bytes bytes)
(for/sum ([b (in-list (reverse bytes))]
[i (in-naturals)])
(* b (expt 16 i))))
(module+ test
(check-equal? #x2B45 (glue-bytes (list #x2 #xB #x4 #x5)))
(check-equal? #xCD (glue-bytes (list #xC #xD)))
(check-equal? #xA (glue-bytes (list #xA)))
(check-equal? #x0 (glue-bytes (list #x0))))
(check-equal? #x2B45 (join-bytes (list #x2 #xB #x4 #x5)))
(check-equal? #xCD (join-bytes (list #xC #xD)))
(check-equal? #xA (join-bytes (list #xA)))
(check-equal? #x0 (join-bytes (list #x0))))
(define-macro (define-memory-vector ID [FIELD LENGTH SIZE] ...)
(with-pattern
@ -50,7 +50,7 @@
(define (PREFIXED-ID-REF idx)
(unless (< idx LENGTH)
(raise-argument-error 'PREFIXED-ID-REF (format "index less than field length ~a" LENGTH) idx))
(glue-bytes
(join-bytes
(for/list ([i (in-range SIZE)])
(vector-ref ID (+ FIELD-OFFSET i idx)))))
...
@ -60,19 +60,38 @@
(unless (< val (expt 16 SIZE))
(raise-argument-error 'PREFIXED-ID-SET! (format "value less than field size ~a" (expt 16 SIZE)) val))
(for ([i (in-range SIZE)]
[b (in-list (explode-bytes val))])
[b (in-list (split-bytes val))])
(vector-set! ID (+ FIELD-OFFSET i idx) b))) ...)))
(define-memory-vector chip
(define-memory-vector chip8
[opcode 1 2] ; two bytes
[memory 4096 1] ; one byte per
[V 16 1] ; one byte per
[I 3 1] ; index register, 0x000 to 0xFFF
[pc 3 1] ; program counter, 0x000 to 0xFFF
[I 2 1] ; index register, 0x000 to 0xFFF (1.5 bytes)
[pc 2 1] ; program counter, 0x000 to 0xFFF (1.5 bytes)
[gfx (* 64 32) 1] ; pixels
[delay_timer 1 1]
[sound_timer 1 1]
[stack 16 2] ; 2 bytes each
[sp 1 1] ; stack pointer
[sp 1 2] ; stack pointer
[key 16 1]) ; keys
;; Set up render system and register input callbacks
;(setup-graphics chip8)
;(setup-input chip8)
;; Initialize the Chip8 system and load the game into the memory
;(initialize chip8)
;(load-game chip8 "pong")
;; Emulation loop
#;(let loop ()
;; Emulate one cycle
(emulate-cycle chip8)
;; If the draw flag is set, update the screen
(when (draw-flag? chip8)
(draw-graphics chip8))
;; Store key press state (Press and Release)
(set-keys chip8)
(loop))