1/* Add two limb vectors of the same length > 0 and store sum in a third
2 limb vector.
3 Copyright (C) 2001-2024 Free Software Foundation, Inc.
4 This file is part of the GNU MP Library.
5
6 The GNU MP Library is free software; you can redistribute it and/or modify
7 it under the terms of the GNU Lesser General Public License as published by
8 the Free Software Foundation; either version 2.1 of the License, or (at your
9 option) any later version.
10
11 The GNU MP Library is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
13 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
14 License for more details.
15
16 You should have received a copy of the GNU Lesser General Public License
17 along with the GNU MP Library; see the file COPYING.LIB. If not,
18 see <https://www.gnu.org/licenses/>. */
19
20/*
21 INPUT PARAMETERS
22 res_ptr %r2
23 s1_ptr %r3
24 s2_ptr %r4
25 size %r5
26*/
27
28#include "sysdep.h"
29#include "asm-syntax.h"
30
31 .text
32ENTRY(__mpn_add_n)
33 stg %r6,48(%r15) # save register 6
34 cfi_offset (%r6,-112)
35 slgr %r1,%r1
36 lghi %r0,1 # cannot use ahi to add carry, use alr
37.L0: lg %r6,0(%r1,%r3) # .L0 -> no carry from last add
38 alg %r6,0(%r1,%r4)
39 stg %r6,0(%r1,%r2)
40 la %r1,8(%r1)
41 brc 3,.L3
42.L1: brct %r5,.L0
43 slgr %r2,%r2 # no last carry to return
44 j .Lexit
45.L2: lg %r6,0(%r1,%r3) # .L2 -> carry from last add
46 alg %r6,0(%r1,%r4)
47 brc 3,.L4
48 algr %r6,%r0 # no carry yet, add carry from last add
49 stg %r6,0(%r1,%r2)
50 la %r1,8(%r1)
51 brc 12,.L1 # new carry ?
52.L3: brct %r5,.L2
53 lgr %r2,%r0 # return last carry
54 j .Lexit
55.L4: algr %r6,%r0 # already a carry, add carry from last add
56 stg %r6,0(%r1,%r2)
57 la %r1,8(%r1)
58 brct %r5,.L2
59 lgr %r2,%r0 # return last carry
60.Lexit: lg %r6,48(%r15) # restore register 6
61 br %r14
62END(__mpn_add_n)
63

source code of glibc/sysdeps/s390/s390-64/add_n.S