+ (error "Unknown mode."))))
+
+
+ ;;; Memory setup and addressing
+ ;;
+
+ (define INITIAL-INSTR (make-instr 'DAT 'F 'immediate 0 'immediate 0))
+
+ (define (make-core core-size . set-functions)
+ (let ((core-vec (make-vector core-size '()))
+ (names-vec (make-vector core-size '())))
+ (define (norm-addr i)
+ (if (< i 0)
+ (norm-addr (+ i core-size))
+ (modulo i core-size)))
+ (define (norm-ref v i)
+ (vector-ref v (norm-addr i)))
+ (define (norm-set! v i x)
+ (vector-set! v (norm-addr i)
+ (if (integer? x)
+ (norm-addr x)
+ x)))
+ (define (run-set-functions i n)
+ (let loop ((remaining-fns set-functions))
+ (unless (null? remaining-fns)
+ ((car remaining-fns) i n))))
+ (define (dump i)
+ (print* i ":\t" ((norm-ref core-vec i) '->string))
+ (let ((n (norm-ref names-vec i)))
+ (unless (null? n)
+ (print* "\t;" n)))
+ (print))
+ (let loop ((i 0))
+ (unless (>= i core-size)
+ (vector-set! core-vec i (INITIAL-INSTR 'make-copy))
+ (loop (+ i 1))))
+ (lambda args
+ (match args
+ ((i 'set-from! j n)
+ ((norm-ref core-vec i) 'set-from! (norm-ref core-vec j))
+ (norm-set! names-vec i n)
+ (run-set-functions i n))
+ ((i 'set-from-instr! instr n)
+ ((norm-ref core-vec i) 'set-from! instr)
+ (norm-set! names-vec i n)
+ (run-set-functions i n))
+ ((i 'set! v x n)
+ ((norm-ref core-vec i) 'set! v x)
+ (norm-set! names-vec i n)
+ (run-set-functions i n))
+ ((i 'name) (norm-ref names-vec i))
+ (((? integer? i) v) ((norm-ref core-vec i) v))
+ (('->addr (? integer? i)) (norm-addr i))
+ (('dump i)
+ (let ((i1 (- i 4))
+ (i2 (+ i 4)))
+ (let loop ((idx i1))
+ (unless (> idx i2)
+ (if (= idx i)
+ (print* "*"))
+ (dump idx)
+ (loop (+ idx 1))))))
+ (('size) core-size)))))
+
+
+ ;;; Programmes and task queues
+ ;;
+
+ (define (make-prog name author instrs offset)
+ (list name author instrs offset))
+
+ (define (prog-name prog) (list-ref prog 0))
+ (define (prog-author prog) (list-ref prog 1))
+ (define (prog-instrs prog) (list-ref prog 2))
+ (define (prog-offset prog) (list-ref prog 3))
+
+ (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 (core '->addr (+ ptr 1)) (cdr instrs))))
+ (make-queue (prog-name prog)
+ (core '->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 (core '->addr (+ ptr 1))
+ (- remaining 1))
+ #f))))
+
+ (define (install-progs core progs)
+ (let loop ((queues '())
+ (progs-left progs))
+ (if (null? progs-left)
+ queues
+ (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) queues)
+ (cdr progs-left))
+ (loop queues progs-left))))))
+
+ (define (make-queue name ptr)
+ (list name ptr))
+
+ (define (queue-owner queue) (car queue))
+ (define (queue-ptrs queue) (cdr queue))
+
+ (define (queue-set-ptrs! queue ptrs)
+ (set-cdr! queue ptrs))
+
+ (define (dump-queue queue core)
+ (let loop ((ptrs (queue-ptrs queue)))
+ (unless (null? ptrs)
+ (core 'dump (car ptrs))
+ (print)
+ (loop (cdr ptrs)))))
+
+ (define (prog->string prog)
+ (conc ";redcode\n\n"
+ ";name\t" (prog-name prog) "\n"
+ (if (not (null? (prog-author prog)))
+ (conc ";author\t" (prog-author prog) "\n\n")
+ "\n")
+ "ORG\t" (prog-offset prog) "\t; Execution offset\n\n"
+ (apply conc (map (lambda (instr) (conc (instr '->string) "\n")) (prog-instrs prog)))))
+
+ (define (dump-prog prog)
+ (print (prog->string prog)))
+
+
+ ;;; Executive function
+ ;;
+
+ (define (run-mars core queues steps-left)
+ (if (or (<= steps-left 0)
+ (null? queues)
+ (= (length queues) 1))
+ queues
+ (let* ((queue (car queues))
+ (remaining-queues (cdr queues))
+ (ptrs (queue-ptrs queue))
+ (new-ptrs (execute-instr core (car ptrs) (queue-owner queue))))
+ (if (null? new-ptrs)
+ (run-mars core remaining-queues (- steps-left 1))
+ (begin
+ (queue-set-ptrs! queue (append (cdr ptrs) new-ptrs))
+ (run-mars core (append remaining-queues (list queue)) (- steps-left 1)))))))
+
+ (define (execute-instr core ptr name)
+ ;; (print ptr "\t" (core ptr '->string) "\t(" 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 (core '->addr (+ ptr 1))))
+ ((ADD)
+ (combine-and-store core A-ptr B-ptr modifier name +)
+ (list (core '->addr (+ ptr 1))))
+ ((SUB)
+ (combine-and-store core A-ptr B-ptr modifier name -)
+ (list (core '->addr (+ ptr 1))))
+ ((MUL)
+ (combine-and-store core A-ptr B-ptr modifier name *)
+ (list (core '->addr (+ ptr 1))))
+ ((DIV)
+ (condition-case
+ (begin
+ (combine-and-store core A-ptr B-ptr modifier name quotient)
+
+ (list (core '->addr (+ ptr 1))))
+ ((exn arithmetic) '())))
+ ((MOD)
+ (condition-case
+ (begin
+ (combine-and-store core A-ptr B-ptr modifier name modulo)
+ (list (core '->addr (+ ptr 1))))
+ ((exn arithmetic) '())))
+ ((JMP)
+ (list (core '->addr A-ptr)))
+ ((JMZ)
+ (list (core '->addr (if (instr-zero? core B-ptr modifier #f name)
+ A-ptr
+ (+ ptr 1)))))
+ ((JMN)
+ (list (core '->addr (if (not (instr-zero? core B-ptr modifier #f name))
+ A-ptr
+ (+ ptr 1)))))
+ ((DJN)
+ (list (core '->addr (if (not (instr-zero? core B-ptr modifier #t name))
+ A-ptr
+ (+ ptr 1)))))
+ ((SEQ CMP)
+ (list (core '->addr (+ ptr (if (compare-instrs core A-ptr B-ptr modifier =) 2 1)))))
+ ((SNE)
+ (list (core '->addr (+ ptr (if (compare-instrs core A-ptr B-ptr modifier =) 1 2)))))
+ ((SLT)
+ (list (core '->addr (+ ptr (if (compare-instrs core A-ptr B-ptr modifier <) 2 1)))))
+ ((SPL)
+ (list (core '->addr (+ ptr 1)) (core '->addr A-ptr)))
+ ((NOP)
+ (list (core '->addr (+ ptr 1))))
+ (else
+ (error "Unrecognised opcode" (core ptr 'opcode))))))
+
+ (define (compare-instrs core A-ptr B-ptr modifier test)
+ (case modifier
+ ((A) (test (core A-ptr 'A-num) (core B-ptr 'A-num)))
+ ((B) (test (core A-ptr 'B-num) (core B-ptr 'B-num)))
+ ((AB) (test (core A-ptr 'A-num) (core B-ptr 'B-num)))
+ ((BA) (test (core A-ptr 'B-num) (core B-ptr 'A-num)))
+ ((F) (and
+ (test (core A-ptr 'A-num) (core B-ptr 'A-num))
+ (test (core A-ptr 'B-num) (core B-ptr 'B-num))))
+ ((X) (and
+ (test (core A-ptr 'A-num) (core B-ptr 'B-num))
+ (test (core A-ptr 'B-num) (core B-ptr 'A-num))))
+ ((I) (and
+ (if (eq? test =)
+ (and
+ (eq? (core A-ptr 'opcode) (core B-ptr 'opcode))
+ (eq? (core A-ptr 'modifier) (core B-ptr 'modifier))
+ (eq? (core A-ptr 'A-mode) (core B-ptr 'B-mode))
+ (eq? (core A-ptr 'B-mode) (core B-ptr 'A-mode)))
+ #t)
+ (test (core A-ptr 'A-num) (core B-ptr 'B-num))
+ (test (core A-ptr 'B-num) (core B-ptr 'A-num))))))
+
+ (define (instr-zero? core ptr modifier decrement name)
+ (case modifier
+ ((A AB)
+ (if decrement (core ptr 'set! 'A-num (- (core ptr 'A-num) 1) name))
+ (= 0 (core ptr 'A-num)))
+ ((A AB)
+ (if decrement (core ptr 'set! 'B-num (- (core ptr 'B-num) 1) name))
+ (= 0 (core ptr 'B-num)))
+ ((X I F)
+ (if decrement
+ (begin
+ (core ptr 'set! 'A-num (- (core ptr 'A-num) 1) name)
+ (core ptr 'set! 'B-num (- (core ptr 'B-num) 1) name)))
+ (and (= 0 (core ptr 'A-num))
+ (= 0 (core ptr '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)
+ (core '->addr (+ ptr
+ (case mode
+ ((immediate) 0)
+ ((direct) num)
+ ((indirect-A) (+ num (core (+ ptr num) 'A-num)))
+ ((indirect-B) (+ num (core (+ ptr num) 'B-num)))
+ ((pre-indirect-A)
+ (let ((aux-ptr (+ ptr num)))
+ (core aux-ptr 'set! 'A-num (- (core aux-ptr 'A-num) 1) name)
+ (+ num (core aux-ptr 'A-num))))
+ ((pre-indirect-B)
+ (let ((aux-ptr (+ ptr num)))
+ (core aux-ptr 'set! 'B-num (- (core aux-ptr 'B-num) 1) name)
+ (+ num (core aux-ptr 'B-num))))
+ ((post-indirect-A)
+ (let* ((aux-ptr (+ ptr num))
+ (old-A-num (core aux-ptr 'A-num)))
+ (core aux-ptr 'set! 'A-num (+ (core aux-ptr 'A-num) 1) name)
+ (+ num old-A-num)))
+ ((post-indirect-B)
+ (let* ((aux-ptr (+ ptr num))
+ (old-B-num (core aux-ptr 'B-num)))
+ (core aux-ptr 'set! 'B-num (+ (core aux-ptr 'B-num) 1) name)
+ (+ num old-B-num)))
+ (else
+ (error "Unrecognized mode" mode)))))))
+