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(in-package "ACL2")
(include-book "data")
(defconst *big-instr-list*
(make-instrs 0 10 nil (expt 10 6) nil))
; An instruction is a list (read addr) or (write addr val), where addr and val
; are natural numbers. A read returns the value read (default 0) from the
; given list of pairs (alist).
(defun read-step (addr alist)
(let ((pair (assoc addr alist)))
(if pair (cdr pair) 0)))
(defun write-step (addr val alist)
(put-assoc-eql addr val alist))
(defun write-p (instr)
(and (true-listp instr)
(eql (length instr) 3)
(eq (car instr) 'write)
(natp (cadr instr))
(natp (caddr instr))))
(defun read-p (instr)
(and (true-listp instr)
(eql (length instr) 2)
(eq (car instr) 'read)
(natp (cadr instr))))
(defun get-addr (instr)
(cadr instr))
(defun get-val (write-instr)
(caddr write-instr))
; A state is a list of pairs (an alist) mapping natural numbers to values.
(defun run (instrs alist reversed-values-read)
(if (endp instrs)
reversed-values-read
(let ((instr (car instrs)))
(run (cdr instrs)
(if (write-p instr)
(write-step (get-addr instr) (get-val instr) alist)
alist)
(if (read-p instr)
(cons (read-step (get-addr instr) alist)
reversed-values-read)
reversed-values-read)))))
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