;; -*- Mode: Lisp; -*-

        ;; Unsigned divison

(defmacro jc (addr) `(progn (jnc (+ @ 2)) (jmp ,addr)))
(defmacro jz (addr) `(progn (jnz (+ @ 2)) (jmp ,addr)))
(defmacro shr () `(progn (asr) (and '#x7FFFFFFF)))

        (:bss)
div.x   (ds 1)                  ;dividend and remainder, when done
div.y   (ds 1)                  ;divisor
div.q   (ds 1)
div.m   (ds 1)
div.tmp (ds 1)
        
        (:text)
div
        (sto div.ret)
        (lod '0) (sto div.q)            ;q = 0
        (lod '1) (sto div.m)            ;m = 1
div.L1
        ;; while x <= 2y, shift both y and m left
        ;; and 2y still fits
        (lod div.y)
        (and '#x80000000)
        (jnz div.L2)
        (lod div.y)
        (add div.y)
        (sto div.tmp)
        (lod div.x)
        (sub div.tmp)
        (jc  div.L2)                    ;2y > x
        (lod div.tmp)
        (sto div.y)                         ;y = y + y
        (lod div.m) (add div.m) (sto div.m) ;m = m + k
        (jmp div.L1)
div.L2
        (lod div.x)
        (sub div.y)
        (jc  div.L3)                    ;y > x
        (sto div.x)
        (lod div.q) (add div.m) (sto div.q) ;q += m
div.L3
        (lod div.m)
        (shr)
        (jz  div.done)
        (sto div.m)
        ;;
        (lod div.y)
	(shr)
	(sto div.y)
        (jmp div.L2)
div.done
        (lod div.q)
div.ret
        (jmp @)