1 ac0e2db6 2004-04-21 devnull /*
 2 ac0e2db6 2004-04-21 devnull  *	mpvecadd(mpdigit *a, int alen, mpdigit *b, int blen, mpdigit *sum)
 3 ac0e2db6 2004-04-21 devnull  *
 4 ac0e2db6 2004-04-21 devnull  *		sum[0:alen] = a[0:alen-1] + b[0:blen-1]
 5 ac0e2db6 2004-04-21 devnull  *
 6 ac0e2db6 2004-04-21 devnull  *	prereq: alen >= blen, sum has room for alen+1 digits
 7 ac0e2db6 2004-04-21 devnull  */
 8 ac0e2db6 2004-04-21 devnull 
 9 ac0e2db6 2004-04-21 devnull .text
10 ac0e2db6 2004-04-21 devnull 
11 ac0e2db6 2004-04-21 devnull .p2align 2,0x90
12 ac0e2db6 2004-04-21 devnull .globl mpvecadd
13 ac0e2db6 2004-04-21 devnull 	.type mpvecadd, @function
14 ac0e2db6 2004-04-21 devnull mpvecadd:
15 ac0e2db6 2004-04-21 devnull 	/* Prelude */
16 ac0e2db6 2004-04-21 devnull 	pushl %ebp
17 ac0e2db6 2004-04-21 devnull 	movl %ebx, -4(%esp)		/* save on stack */
18 ac0e2db6 2004-04-21 devnull 	movl %esi, -8(%esp)
19 ac0e2db6 2004-04-21 devnull 	movl %edi, -12(%esp)
20 ac0e2db6 2004-04-21 devnull 
21 ac0e2db6 2004-04-21 devnull 	movl	12(%esp), %edx		/* alen */
22 ac0e2db6 2004-04-21 devnull 	movl	20(%esp), %ecx		/* blen */
23 ac0e2db6 2004-04-21 devnull 	movl	8(%esp), %esi		/* a */
24 ac0e2db6 2004-04-21 devnull 	movl	16(%esp), %ebx		/* b */
25 ac0e2db6 2004-04-21 devnull 	subl	%ecx, %edx
26 ac0e2db6 2004-04-21 devnull 	movl	24(%esp), %edi		/* sum */
27 ac0e2db6 2004-04-21 devnull 	xorl	%ebp, %ebp		/* this also sets carry to 0 */
28 ac0e2db6 2004-04-21 devnull 
29 ac0e2db6 2004-04-21 devnull 	/* skip addition if b is zero */
30 ac0e2db6 2004-04-21 devnull 	testl	%ecx,%ecx
31 ac0e2db6 2004-04-21 devnull 	je	_add1
32 ac0e2db6 2004-04-21 devnull 
33 ac0e2db6 2004-04-21 devnull 	/* sum[0:blen-1],carry = a[0:blen-1] + b[0:blen-1] */
34 ac0e2db6 2004-04-21 devnull _addloop1:
35 ac0e2db6 2004-04-21 devnull 	movl	(%esi, %ebp, 4), %eax
36 ac0e2db6 2004-04-21 devnull 	adcl	(%ebx, %ebp, 4), %eax
37 ac0e2db6 2004-04-21 devnull 	movl	%eax, (%edi, %ebp, 4)
38 ac0e2db6 2004-04-21 devnull 	incl	%ebp
39 ac0e2db6 2004-04-21 devnull 	loop	_addloop1
40 ac0e2db6 2004-04-21 devnull 
41 ac0e2db6 2004-04-21 devnull _add1:
42 ac0e2db6 2004-04-21 devnull 	/* jump if alen > blen */
43 ac0e2db6 2004-04-21 devnull 	incl	%edx
44 ac0e2db6 2004-04-21 devnull 	movl	%edx, %ecx
45 ac0e2db6 2004-04-21 devnull 	loop	_addloop2
46 ac0e2db6 2004-04-21 devnull 
47 ac0e2db6 2004-04-21 devnull 	/* sum[alen] = carry */
48 ac0e2db6 2004-04-21 devnull _addend:
49 ac0e2db6 2004-04-21 devnull 	jb	_addcarry
50 ac0e2db6 2004-04-21 devnull 	movl	$0, (%edi, %ebp, 4)
51 ac0e2db6 2004-04-21 devnull 	jmp done
52 ac0e2db6 2004-04-21 devnull 
53 ac0e2db6 2004-04-21 devnull _addcarry:
54 ac0e2db6 2004-04-21 devnull 	movl	$1, (%edi, %ebp, 4)
55 ac0e2db6 2004-04-21 devnull 	jmp done
56 ac0e2db6 2004-04-21 devnull 
57 ac0e2db6 2004-04-21 devnull 	/* sum[blen:alen-1],carry = a[blen:alen-1] + 0 */
58 ac0e2db6 2004-04-21 devnull _addloop2:
59 ac0e2db6 2004-04-21 devnull 	movl	(%esi, %ebp, 4),%eax
60 ac0e2db6 2004-04-21 devnull 	adcl	$0, %eax
61 ac0e2db6 2004-04-21 devnull 	movl	%eax, (%edi, %ebp, 4)
62 ac0e2db6 2004-04-21 devnull 	incl	%ebp
63 ac0e2db6 2004-04-21 devnull 	loop	_addloop2
64 ac0e2db6 2004-04-21 devnull 	jmp	_addend
65 ac0e2db6 2004-04-21 devnull 
66 ac0e2db6 2004-04-21 devnull done:
67 ac0e2db6 2004-04-21 devnull 	/* Postlude */
68 ac0e2db6 2004-04-21 devnull 	movl -4(%esp), %ebx		/* restore from stack */
69 ac0e2db6 2004-04-21 devnull 	movl -8(%esp), %esi
70 ac0e2db6 2004-04-21 devnull 	movl -12(%esp), %edi
71 ac0e2db6 2004-04-21 devnull 	movl %esp, %ebp
72 ac0e2db6 2004-04-21 devnull 	leave
73 ac0e2db6 2004-04-21 devnull 	ret