div4x2.asm

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;
;  R4R5R6R7  = R4R5R6R7 / R2R3
; (R0R1)R2R3 = R4R5R6R7 % R2R3
;
; use Acc,B,R0..R7
;

.global	div4x2

div4x2:	mov	b,#32		;bit counter = 32 bit
	mov	r0,#0
	mov	r1,#0
Lloop:	mov	a,r7
	add	a,r7
	mov	r7,a
	mov	a,r6
	rlc	a
	mov	r6,a
	mov	a,r5
	rlc	a
	mov	r5,a
	mov	a,r4
	rlc	a
	mov	r4,a
	mov	a,r1
	rlc	a
	mov	r1,a
	xch	a,r0
	rlc	a
	xch	a,r0
	jbc	CY,L1xxxx
	subb	a,r3		; R1 - R3
	mov	a,r0
	subb	a,r2		; R0 - R2
	jc	Llt
L1xxxx:	mov	a,r1
	subb	a,r3
	mov	r1,a
	mov	a,r0
	subb	a,r2
	mov	r0,a
	inc	r7
Llt:	djnz	b,Lloop
	clr	a
	xch	a,r0
	mov	r2,a
	clr	a
	xch	a,r1
	mov	r3,a
	ret