1/* __mpn_sub_n -- Add two limb vectors of the same length > 0 and store
2   sum in a third limb vector.  64 bit S/390 version.
3   Copyright (C) 2001-2022 Free Software Foundation, Inc.
4   This file is part of the GNU MP Library.
5
6   The GNU C Library is free software; you can redistribute it and/or
7   modify it under the terms of the GNU Lesser General Public License as
8   published by the Free Software Foundation; either version 2.1 of the
9   License, or (at your option) any later version.
10
11   The GNU C Library is distributed in the hope that it will be useful,
12   but WITHOUT ANY WARRANTY; without even the implied warranty of
13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14   Lesser General Public License for more details.
15
16   You should have received a copy of the GNU Lesser General Public
17   License along with the GNU C Library; see the file COPYING.LIB.  If not,
18   see <https://www.gnu.org/licenses/>.  */
19
20/* INPUT PARAMETERS
21     %r2 = res_ptr
22     %r3 = s1_ptr
23     %r4 = s2_ptr
24     %r5 = size.  */
25
26#include "sysdep.h"
27#include "asm-syntax.h"
28
29ENTRY(__mpn_sub_n)
30        stg    %r6,48(%r15)   # save register 6
31	cfi_offset (%r6,-112)
32        sgr    %r1,%r1
33        lghi   %r0,1          # cannot use ahi to add carry, use slr
34.L0:	lg     %r6,0(%r1,%r3) # .L0 -> no carry from last sub
35	slg    %r6,0(%r1,%r4)
36	stg    %r6,0(%r1,%r2)
37	la     %r1,8(%r1)
38	brc    4,.L3
39.L1:	brct   %r5,.L0
40	slgr   %r2,%r2	      # no last carry to return
41	j      .Lexit
42.L2:	lg     %r6,0(%r1,%r3) # .L2 -> carry from last sub
43	slg    %r6,0(%r1,%r4)
44	brc    4,.L4
45	slgr   %r6,%r0	      # no carry yet, add carry from last sub
46	stg    %r6,0(%r1,%r2)
47	la     %r1,8(%r1)
48	brc    11,.L1	      # new carry ?
49.L3:	brct   %r5,.L2
50	lgr    %r2,%r0	      # return last carry
51	j      .Lexit
52.L4:	slgr   %r6,%r0	      # already a carry, add carry from last sub
53	stg    %r6,0(%r1,%r2)
54	la     %r1,8(%r1)
55	brct   %r5,.L2
56	lgr    %r2,%r0	      # return last carry
57.Lexit: lg     %r6,48(%r15)   # restore register 6
58	br     %r14
59END(__mpn_sub_n)
60