;=======================================================================
;Assembly Language Tutorial for the SX Microcontroller
;Program 5.2
;=======================================================================
		device	sx28l,oschs3
		device	turbo,stackx,optionx
		IRC_CAL	IRC_SLOW
		reset	start_point
		freq	50000000	; 50 MHz

		org	8
dividend	ds	1
divisor		ds	1
quotient	ds	1
counter		ds	1
		watch 	dividend,8,udec
		watch 	divisor,8,udec
		watch 	quotient,8,udec
		watch 	counter,8,udec

		org	0
start_point 
		mov	dividend,#20
		mov	divisor,#5
		call	divide
		break
		nop
		sleep

; subroutine

divide		clr	counter		; assume not dividing by zero
		clc
:loop		rl	divisor
		inc	counter
		jnc	:loop
; restore divisor so top bit is 1
		rr	divisor  
; counter has number of bits in quotient
		clr	quotient
:dloop
		test	counter
		jz	:done
		clc
		rl	quotient
		cjb	dividend,divisor,:dloop1
		sub	dividend,divisor
		inc	quotient
:dloop1		
		dec	counter
		clc
		rr	divisor
		jmp	:dloop
:done
		ret			; go back to wherever