sicp ch5 wisp machines

-*- wisp -*-
;; full-definition
define machine
  data-paths
    registers
      : name a
	buttons
	  : name a<-b
	    source : register b
      : name b
	buttons
	  : name b<-t
	    source : register b
      : name t
	buttons
	  : name t<-r
	    source : operation rem
    operations
      : name rem
        inputs
	  register a
	  register b
      : name =
        inputs
	  register b
	  constant 0
  controller
    . test-b
    test =
    branch : label gcd-done
    t<-r
    a<-b
    b<-t
    goto : label test-b
    . gcd-done

;; abbreviated machine def
define program
  quote
    ;; pseudo assembly
    controller
      . test-b		; label
      test
        op =
        reg b
	const 0
      branch
        label gcd-done
      assign t
        op rem
	reg a
	reg b
      assign a
        reg b
      assign b
        reg t
      goto
        label test-b
      . gcd-done	; label


define program-compressed
  quote
    ;; pseudo assembly
    controller
      . test-b		; label
      test (op =) (reg b) (const 0)
      branch : label gcd-done
      assign t (op rem) (reg a) (reg b)
      assign a : reg b
      assign b : reg t
      goto : label test-b
      . gcd-done	; label