1 a32765e3 2005-08-10 devnull /*	mpvecadd(mpdigit *a, int alen, mpdigit *b, int blen, mpdigit *sum) */
 2 a32765e3 2005-08-10 devnull /*		sum[0:alen] = a[0:alen-1] + b[0:blen-1] */
 3 a32765e3 2005-08-10 devnull /*	prereq: alen >= blen, sum has room for alen+1 digits */
 4 a32765e3 2005-08-10 devnull /* (very old gnu assembler doesn't allow multiline comments) */
 5 ac0e2db6 2004-04-21 devnull 
 6 ac0e2db6 2004-04-21 devnull .text
 7 ac0e2db6 2004-04-21 devnull 
 8 ac0e2db6 2004-04-21 devnull .p2align 2,0x90
 9 ac0e2db6 2004-04-21 devnull .globl mpvecadd
10 ac0e2db6 2004-04-21 devnull mpvecadd:
11 ac0e2db6 2004-04-21 devnull 	/* Prelude */
12 39ce0d58 2006-03-22 devnull 	pushl %ebp		/* save on stack */
13 39ce0d58 2006-03-22 devnull 	pushl %ebx
14 39ce0d58 2006-03-22 devnull 	pushl %esi
15 39ce0d58 2006-03-22 devnull 	pushl %edi
16 ac0e2db6 2004-04-21 devnull 
17 39ce0d58 2006-03-22 devnull 	leal 20(%esp), %ebp		/* %ebp = FP for now */
18 39ce0d58 2006-03-22 devnull 
19 39ce0d58 2006-03-22 devnull 	movl	4(%ebp), %edx		/* alen */
20 39ce0d58 2006-03-22 devnull 	movl	12(%ebp), %ecx		/* blen */
21 39ce0d58 2006-03-22 devnull 	movl	0(%ebp), %esi		/* a */
22 39ce0d58 2006-03-22 devnull 	movl	8(%ebp), %ebx		/* b */
23 ac0e2db6 2004-04-21 devnull 	subl	%ecx, %edx
24 39ce0d58 2006-03-22 devnull 	movl	16(%ebp), %edi		/* sum */
25 ac0e2db6 2004-04-21 devnull 	xorl	%ebp, %ebp		/* this also sets carry to 0 */
26 ac0e2db6 2004-04-21 devnull 
27 ac0e2db6 2004-04-21 devnull 	/* skip addition if b is zero */
28 ac0e2db6 2004-04-21 devnull 	testl	%ecx,%ecx
29 ac0e2db6 2004-04-21 devnull 	je	_add1
30 ac0e2db6 2004-04-21 devnull 
31 ac0e2db6 2004-04-21 devnull 	/* sum[0:blen-1],carry = a[0:blen-1] + b[0:blen-1] */
32 ac0e2db6 2004-04-21 devnull _addloop1:
33 ac0e2db6 2004-04-21 devnull 	movl	(%esi, %ebp, 4), %eax
34 ac0e2db6 2004-04-21 devnull 	adcl	(%ebx, %ebp, 4), %eax
35 ac0e2db6 2004-04-21 devnull 	movl	%eax, (%edi, %ebp, 4)
36 ac0e2db6 2004-04-21 devnull 	incl	%ebp
37 ac0e2db6 2004-04-21 devnull 	loop	_addloop1
38 ac0e2db6 2004-04-21 devnull 
39 ac0e2db6 2004-04-21 devnull _add1:
40 ac0e2db6 2004-04-21 devnull 	/* jump if alen > blen */
41 ac0e2db6 2004-04-21 devnull 	incl	%edx
42 ac0e2db6 2004-04-21 devnull 	movl	%edx, %ecx
43 ac0e2db6 2004-04-21 devnull 	loop	_addloop2
44 ac0e2db6 2004-04-21 devnull 
45 ac0e2db6 2004-04-21 devnull 	/* sum[alen] = carry */
46 ac0e2db6 2004-04-21 devnull _addend:
47 ac0e2db6 2004-04-21 devnull 	jb	_addcarry
48 ac0e2db6 2004-04-21 devnull 	movl	$0, (%edi, %ebp, 4)
49 ac0e2db6 2004-04-21 devnull 	jmp done
50 ac0e2db6 2004-04-21 devnull 
51 ac0e2db6 2004-04-21 devnull _addcarry:
52 ac0e2db6 2004-04-21 devnull 	movl	$1, (%edi, %ebp, 4)
53 ac0e2db6 2004-04-21 devnull 	jmp done
54 ac0e2db6 2004-04-21 devnull 
55 ac0e2db6 2004-04-21 devnull 	/* sum[blen:alen-1],carry = a[blen:alen-1] + 0 */
56 ac0e2db6 2004-04-21 devnull _addloop2:
57 ac0e2db6 2004-04-21 devnull 	movl	(%esi, %ebp, 4),%eax
58 ac0e2db6 2004-04-21 devnull 	adcl	$0, %eax
59 ac0e2db6 2004-04-21 devnull 	movl	%eax, (%edi, %ebp, 4)
60 ac0e2db6 2004-04-21 devnull 	incl	%ebp
61 ac0e2db6 2004-04-21 devnull 	loop	_addloop2
62 ac0e2db6 2004-04-21 devnull 	jmp	_addend
63 ac0e2db6 2004-04-21 devnull 
64 ac0e2db6 2004-04-21 devnull done:
65 ac0e2db6 2004-04-21 devnull 	/* Postlude */
66 39ce0d58 2006-03-22 devnull 	popl %edi
67 39ce0d58 2006-03-22 devnull 	popl %esi
68 39ce0d58 2006-03-22 devnull 	popl %ebx
69 39ce0d58 2006-03-22 devnull 	popl %ebp
70 ac0e2db6 2004-04-21 devnull 	ret