| 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) 2001-2024 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 | |
|---|
| 29 | ENTRY(__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 |
|---|
| 59 | END(__mpn_sub_n) |
|---|
| 60 | |
|---|
