;; Jam2000 0.91 --- Last updated: April 1, 1996
;; 
;; Author: Matthias Felleisen, Eric Virro
;; Design: Cartwright, Felleisen, Lu, Virro

;; ------------------------------------------------------------------
;; The "Physical" Aspects of the Machine

;; 0 <= memory address < MAX-ADD
(define MAX-ADD 10000)
;; Number of digits in a memory cell value
(define DIGITS 8)
;; -MAX-VAL < memory value < MAX-VAL
(define MAX-VAL (expt 10 DIGITS))
(define MAX-DIGITS-INDEX (sub1 DIGITS))  
;; -MAX-IMM < immediate value < MAX-IMM
(define MAX-IMM 1000000)            
;; 0 <= register number < MAX-REG
(define MAX-REG 10)
(define MAX-REG-INDEX (sub1 MAX-REG))

(define address?
  (lambda (n) (and (number? n) (>= n 0) (< n MAX-ADD))))

(define value?
  (lambda (n) (and (number? n) (< (abs n) MAX-VAL))))

(define immediate?
  (lambda (n) (and (number? n) (< (abs n) MAX-IMM))))

(define register?
  (lambda (n) (and (number? n) (>= n 0) (< n MAX-REG))))