mc8051fun/long_xtobcd.c

/*
r0 = bin
r1 = bcd
r7 = len of bin
r6 = len of bcd
*/

#include "mc8051fun.h"

// double dabble

void long_xtobcd() __naked
{
	__asm
.globl long_xtobcd
	
long_xtobcd:

	; fill dst with zeroes

	mov	r3,AR1		; save r1 in r3
	mov	r4,AR6		; use r4 as counter
	mov	a,#0x00

000$:
	movx	@r1,a
	inc	r1
	djnz	r4,000$

	mov	a,r0
	add	a,r7
	dec	a
	mov	r0,a
	mov	r2,AR0		; save r0 in r2	

006$:	
	movx 	a,@r0
	mov	r5,#0x08
005$:
	mov	r4,AR6		; use r4 as counter
	mov	r1,AR3

	push 	ACC
004$:
	movx	a,@r1
	acall	003$
	acall	003$
	movx	@r1,a
	inc	r1
	djnz	r4,004$

	pop	ACC


	rlc	a
	push 	ACC
	push	AR0
	push	AR7
	mov	r7,AR6
	mov	r0,AR3
	lcall	long_xrlc
	pop 	AR7
	pop	AR0
	pop	ACC
	djnz	r5,005$


	dec	r0
	djnz	r7,006$
	ret
	

003$:
	swap	a
	clr	c
	subb	a,#0x50
	jc	002$
	add	a,#0x30
002$:
	add	a,#0x50
	ret
	
__endasm;
}