mc8051fun/long_xadd.c

/**
 * Add two longs in xmem zero page
 *
 * r0 = ptr to firts arg
 * r1 = ptr to second arg
 * r7 = length
 *
 * result is in r0*
 */

void long_xadd() __naked
{
	__asm
	.globl long_xadd
	.globl long_xaddc
long_xadd:
	clr	c
long_xaddc:
	movx	a,@r1
	mov	b,a
	movx	a,@r0
	addc	a,b
	movx	@r0,a
	inc	r0
	inc	r1
	djnz	r7,long_xaddc
	ret
	__endasm;
}