;;; ;;; An implementation of the Memory Array Redcode Simulator (MARS) ;;; (import (chicken io) (chicken string) (chicken random) (chicken condition) (chicken process context) matchable) ;;; Constants ;; (define core-size 20) (define max-steps 10000) ;;; Instructions ;; (define (make-instr opcode modifier A-mode A-num B-mode B-num) (lambda args (match args (('opcode) opcode) (('modifier) modifier) (('A-mode) A-mode) (('A-num) A-num) (('B-mode) B-mode) (('B-num) B-num) (('make-copy) (make-instr opcode modifier A-mode A-num B-mode B-num)) (('set! 'opcode x) (set! opcode x)) (('set! 'modifier x) (set! modifier x)) (('set! 'A-mode x) (set! A-mode x)) (('set! 'A-num x) (set! A-num x)) (('set! 'B-mode x) (set! B-mode x)) (('set! 'B-num x) (set! B-num x)) (('set-from! other) (set! opcode (other 'opcode)) (set! modifier (other 'opcode)) (set! A-mode (other 'A-mode)) (set! A-num (other 'A-num)) (set! B-mode (other 'B-mode)) (set! B-num (other 'B-num))) (else (error "Invalid instr arguments" args))))) (define (mode->string mode) (case mode ((immediate) "#") ((direct) "$") ((indirect-A) "*") ((indirect-B) "@") ((pre-indirect-A) "{") ((pre-indirect-B) "<") ((post-indirect-A) "}") ((post-indirect-B) ">") (else (error "Unknown mode.")))) (define (instr->string instr) (conc opcode "." modifier " " (mode->string A-mode) A-num " " (mode->string B-mode) B-num)) (define initial-instruction (make-instr 'DAT 'F 'immediate 0 'immediate 0)) ;;; Memory setup and addressing ;; (define (make-core core-size initial-instr) (let ((core-vec (make-vector core-size '())) (names-vec (make-vector core-size '()))) (let loop ((i 0)) (unless (>= i core-size) (vector-set! core-vec i (initial-instr 'copy)) (loop (+ i 1)))) (lambda args (match args ((i 'set-from! j n) ((vector-ref core-vec i) 'set-from! (vector-ref core-vec j)) (vector-set! names-vec i n)) ((i 'set-from-instr! instr n) ((vector-ref core-vec i) 'set-from! instr) (vector-set! names-vec i n)) ((i 'set! v x n) ((vector-ref core-vec i) 'set! v x) (vector-set! names-vec i n)) ((i 'name) (vector-ref names i)) ((i v) ((vector-ref core-vec i) v)) (('dump) (let loop ((i 0)) (unless (>= i core-size) (print* i ":\t") (let ((n (vector-ref names-vec i))) (unless (null? n) (print* "\t;" n))) (print)))))))) (define (addr+ . args) (foldl (lambda (a b) (modulo (+ a b core-size) core-size)) 0 args)) ;;; Programmes and task queues ;; (define (make-prog name instrs offset) (list name instrs offset)) (define (prog-name prog) (list-ref prog 0)) (define (prog-instrs prog) (list-ref prog 1)) (define (prog-offset prog) (list-ref prog 2)) (define (install-prog core prog addr) (let loop ((ptr addr) (instrs (prog-instrs prog))) (unless (null? instrs) (core ptr 'set-from-instr! (car instrs) (prog-name prog)) (loop (addr+ ptr 1) (cdr instrs)))) (make-player (prog-name prog) (addr+ addr (prog-offset prog)))) (define (can-install-prog? core prog-len addr) (let loop ((ptr addr) (remaining prog-len)) (if (= remaining 0) #t (if (null? (core ptr 'name)) (loop (addr+ ptr 1) (- remaining 1)) #f)))) (define (install-progs core progs) (let loop ((players '()) (progs-left progs)) (if (null? progs-left) players (let ((addr (pseudo-random-integer core-size)) (prog (car progs-left))) (if (can-install-prog? core (length (prog-instrs prog)) addr) (loop (cons (install-prog core prog addr) players) (cdr progs-left)) (loop players progs-left)))))) (define (make-queue name ptr) (list name ptr)) (define (queue-owner queue) (car player)) (define (queue-ptrs queue) (cdr queue)) (define (queue-set-ptrs! queue ptrs) (set-cdr! queue ptrs)) ;;; Executive function ;; (define (run core queues steps-left) (cond ((<= steps-left 0) queues) ;Tie between remaining players ;; ((<= (length queues) 1) queues) ;There's only one player left who thus wins (else (let* ((queue (car queues)) (remaining-queues (cdr queues)) (ptrs (queue-ptrs queues)) (new-ptrs (execute-instr core (car ptrs) (queue-owner queue)))) (if (null? new-ptrs) (run other-players (- steps-left 1)) (begin (player-set-ptrs! player (append (cdr ptrs) new-ptrs)) (run (append other-players (list player)) (- steps-left 1)))))))) (define (execute-instr core ptr name) (let* ((A-ptr (eval-operand core (core ptr 'A-mode) (core ptr 'A-num) ptr name)) (B-ptr (eval-operand core (core ptr 'B-mode) (core ptr 'B-num) ptr name)) (modifier (core ptr 'modifier))) (case (core ptr 'opcode) ((DAT) '()) ;Game over, man, game over! ((MOV) (if (eq? modifier 'I) (core B-ptr 'set-from! A-ptr name) (combine-and-store core A-ptr B-ptr modifier name (lambda (x y) y))) (list (addr+ ptr 1))) ((ADD) (combine-and-store core A-ptr B-ptr modifier name addr+) (list (addr+ ptr 1))) ((SUB) (combine-and-store core A-ptr B-ptr modifier name (lambda (x y) (addr+ x (- y)))) (list (addr+ ptr 1))) ((MUL) (combine-and-store core A-ptr B-ptr modifier name (lambda (x y) (modulo (* (addr+ x core-size) (addr+ y core-size)) core-size))) (list (addr+ ptr 1))) ((DIV) (condition-case (begin (combine-and-store core A-ptr B-ptr modifier name (lambda (x y) (quotient (addr x core-size) (addr y core-size)))) (list (addr+ ptr 1))) ((exn arithmetic) '()))) ((MOD) (condition-case (begin (combine-and-store core A-ptr B-ptr modifier name (lambda (x y) (remainder (addr x core-size) (addr y core-size)))) (list (addr+ ptr 1))) ((exn arithmetic) '()))) ((JMP) (list (addr+ ptr (core A-ptr 'A-num)))) ((JMZ) (list (addr+ ptr (if (instr-zero? B-ptr modifier #f) ((core-get A-ptr) 'A-num) 1)))) ((JMN) (list (addr+ ptr (if (not (instr-zero? B-ptr modifier #f)) ((core-get A-ptr) 'A-num) 1)))) ((DJN) (list (addr+ ptr (if (not (instr-zero? B-ptr modifier #t)) ((core-get A-ptr) 'A-num) 1)))) ((SEQ CMP) (list (addr+ ptr (if (compare-instrs A-ptr B-ptr modifier =) 2 1)))) ((SNE) (list (addr+ ptr (if (compare-instrs A-ptr B-ptr modifier =) 1 2)))) ((SLT) (list (addr+ ptr (if (compare-instrs A-ptr B-ptr modifier <) 2 1)))) ((SPL) (list (addr+ ptr 1) (addr+ ptr ((core-get A-ptr) 'A-num)))) ((NOP) (list (addr+ ptr 1))) (else (error "Unrecognised opcode" (instr 'opcode)))))) (define (compare-instrs A-ptr B-ptr modifier test) (let ((A-instr (core-get A-ptr)) (B-instr (core-get B-ptr))) (case modifier ((A) (test (A-instr 'A-num) (B-instr 'A-num))) ((B) (test (A-instr 'B-num) (B-instr 'B-num))) ((AB) (test (A-instr 'A-num) (B-instr 'B-num))) ((BA) (test (A-instr 'B-num) (B-instr 'A-num))) ((F) (and (test (A-instr 'A-num) (B-instr 'A-num)) (test (A-instr 'B-num) (B-instr 'B-num)))) ((X) (and (test (A-instr 'A-num) (B-instr 'B-num)) (test (A-instr 'B-num) (B-instr 'A-num)))) ((I) (and (if (eq? test =) (and (eq? (A-instr 'opcode) (B-instr 'opcode)) (eq? (A-instr 'modifier) (B-instr 'modifier)) (eq? (A-instr 'A-mode) (B-instr 'B-mode)) (eq? (A-instr 'B-mode) (B-instr 'A-mode))) #t) (test (A-instr 'A-num) (B-instr 'B-num)) (test (A-instr 'B-num) (B-instr 'A-num))))))) (define (instr-zero? ptr modifier decrement) (let ((instr (core-get ptr))) (case modifier ((A AB) (if decrement (instr 'set-A-num! (addr+ (instr 'A-num) -1))) (= 0 (instr 'A-num))) ((A AB) (if decrement (instr 'set-B-num! (addr+ (instr 'B-num) -1))) (= 0 (instr 'B-num))) ((X I F) (if decrement (begin (instr 'set-A-num! (addr+ (instr 'A-num) -1)) (instr 'set-B-num! (addr+ (instr 'B-num) -1)))) (and (= 0 (instr 'A-num)) (= 0 (instr 'B-num))))))) (define (combine-and-store core A-ptr B-ptr modifier name f) (case modifier ((A) (core B-ptr 'set! 'A-num (f (core B-ptr 'A-num) (core A-ptr 'A-num)) name)) ((B) (core B-ptr 'set! 'B-num (f (core B-ptr 'B-num) (core A-ptr 'B-num)) name)) ((AB) (core B-ptr 'set! 'B-num (f (core B-ptr 'B-num) (core A-ptr 'A-num)) name)) ((BA) (core B-ptr 'set! 'A-num (f (core B-ptr 'A-num) (core A-ptr 'B-num)) name)) ((F I) (core B-ptr 'set! 'A-num (f (core B-ptr 'A-num) (core A-ptr 'A-num)) name) (core B-ptr 'set! 'B-num (f (core B-ptr 'B-num) (core A-ptr 'B-num)) name)) ((X) (core B-ptr 'set! 'A-num (f (core B-ptr 'A-num) (core A-ptr 'B-num)) name) (core B-ptr 'set! 'B-num (f (core B-ptr 'B-num) (core A-ptr 'A-num)) name)))) (define (eval-operand core mode num ptr name) (addr+ ptr (case mode ((immediate) 0) ((direct) num) ((indirect-A) (addr+ num (core (addr+ ptr num) 'A-num))) ((indirect-B) (addr+ num (core (addr+ ptr num) 'B-num))) ((pre-indirect-A) (let ((aux-ptr (addr+ ptr num))) (core aux-ptr 'set! 'A-num (addr+ -1 (core aux-ptr 'A-num)) name) (addr+ num (core aux-ptr 'A-num)))) ((pre-indirect-B) (let ((aux-ptr (addr+ ptr num))) (core aux-ptr 'set! 'B-num (addr+ -1 (core aux-ptr 'B-num)) name) (addr+ num (core aux-ptr 'B-num)))) ((post-indirect-A) (let* ((aux-ptr (addr+ ptr num)) (old-A-num (core aux-ptr 'A-num))) (core aux-ptr 'set! 'A-num (addr+ 1 (core aux-ptr 'A-num)) name) (addr+ num old-A-num))) ((post-indirect-B) (let* ((aux-ptr (addr+ ptr num)) (old-B-num (core aux-ptr 'B-num))) (core aux-ptr 'set! 'B-num (addr+ 1 (core aux-ptr 'B-num)) name) (addr+ num old-B-num))) (else (error "Unrecognized mode" mode))))) ;;; Main procedure ;; ;;; TEST CODE (define addressing-test (make-prog 'at (list (make-instr 'DAT 'F 'immediate 42 'immediate 53 'at) (make-instr 'DAT 'F 'immediate 123 'immediate 256 'at) (make-instr 'MOV 'A 'indirect-B 4 'direct 7 'at) (make-instr 'NOP 'I 'immediate 0 'immediate 0 'at) (make-instr 'NOP 'I 'immediate 0 'immediate 0 'at) (make-instr 'NOP 'I 'immediate 0 'immediate 0 'at) (make-instr 'DAT 'F 'immediate -5 'immediate -6 'at)) 2)) (define imp (make-prog 'imp (list (make-instr 'MOV 'I 'direct 0 'direct 1 'imp)) 0)) (define dwarf (make-prog 'dwarf (list (make-instr 'DAT 'F 'immediate 0 'immediate -1 'dwarf) (make-instr 'ADD 'AB 'immediate 5 'direct -1 'dwarf) (make-instr 'MOV 'I 'direct -2 'indirect-B -2 'dwarf) (make-instr 'JMP 'I 'immediate -2 'immediate 0 'dwarf)) 1)) (initialize-core) (define players (install-progs (list dwarf imp))) (dump-core)