master
Matthew Butterick 5 years ago
parent fa1327e70c
commit 82d5a1decd

@ -0,0 +1,76 @@
#lang br
(require racket/file rackunit)
(define (string->ints str) (map string->number (string-split str #px",\\s*")))
(define (string->regs str) (list->vector (string->ints str)))
(define ((binarize proc) x y) (if (proc x y) 1 0))
(define (make-runner program [calling-thd (current-thread)])
(thread (λ ()
(define regs (string->regs program))
(define (maybe-enlarge-regs ptr)
(unless (< ptr (vector-length regs))
(define newvec (make-vector (add1 ptr) 0))
(vector-copy! newvec 0 regs)
(set! regs newvec))
regs)
(define (reg-ref ptr) (vector-ref (maybe-enlarge-regs ptr) ptr))
(define (reg-set! ptr val) (vector-set! (maybe-enlarge-regs ptr) ptr val))
(define relative-base 0)
(let/ec terminate
(let loop ([ptr 0])
(define inst (for/list ([c (in-string (~r (reg-ref ptr) #:min-width 5 #:pad-string "0"))])
(string->number (string c))))
(define-values (opcode resolve)
(match inst
[(list d4 d3 d2 d1 d0)
(values (+ (* 10 d1) d0)
(λ (ptr offset)
(define parameter-value (match offset [1 d2] [2 d3] [3 d4]))
(define ptr-resolver (match parameter-value
[0 reg-ref] ; position
[1 values] ; immediate
[2 (compose1 (λ (ptr) (+ relative-base ptr)) reg-ref)])); relative
(ptr-resolver (+ ptr offset))))]))
(define next-ptr
(match opcode
[(or 1 2 7 8) ; 4-arity: add & multiply & compare
(reg-set! (resolve ptr 3) ((match opcode
[1 +]
[2 *]
[7 (binarize <)]
[8 (binarize =)]) (reg-ref (resolve ptr 1)) (reg-ref (resolve ptr 2))))
(+ ptr 4)]
[(or 3 4 9) ; 2-arity: input & output
(match opcode
[3 (reg-set! (resolve ptr 1) 0)]
[4 (thread-send calling-thd (reg-ref (resolve ptr 1)))]
[9 (set! relative-base (+ relative-base (reg-ref (resolve ptr 1))))])
(+ ptr 2)]
[(or 5 6) ; 3-arity: jump
(if ((match opcode
[5 not]
[6 values]) (zero? (reg-ref (resolve ptr 1))))
(reg-ref (resolve ptr 2))
(+ ptr 3))]
[99 (thread-send calling-thd 'done) (terminate)]
[_ (error "unknown opcode" opcode)]))
(loop next-ptr))))))
(define (get-sprites x)
(define thd (match x
[(? thread?) x]
[_ (make-runner x)]))
(for/list ([out (in-producer thread-receive 'done)])
out))
;; 1
(require racket/sequence)
(define pixels
(for/hash ([xyz (in-slice 3 (get-sprites (file->string "13.rktd")))])
(values (list (first xyz) (second xyz)) (third xyz))))
(check-eq?
(count (curry = 2) (hash-values pixels))
304)

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