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/* __mpn_sub_n -- Add two limb vectors of the same length > 0 and store
sum in a third limb vector.
Copyright (C) 2000-2020 Free Software Foundation, Inc.
Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com).
This file is part of the GNU MP Library.
The GNU MP Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or (at your
option) any later version.
The GNU MP Library is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with the GNU MP Library; see the file COPYING.LIB. If not,
see <https://www.gnu.org/licenses/>. */
/*
INPUT PARAMETERS
res_ptr %r2
s1_ptr %r3
s2_ptr %r4
size %r5
*/
#include "sysdep.h"
#include "asm-syntax.h"
ENTRY(__mpn_sub_n)
st %r6,24(%r15) # save register 6
cfi_offset (%r6, -72)
sr %r1,%r1
lhi %r0,1 # cannot use ahi to add carry, use slr
.L0: l %r6,0(%r1,%r3) # .L0 -> no carry from last sub
sl %r6,0(%r1,%r4)
st %r6,0(%r1,%r2)
la %r1,4(0,%r1)
brc 4,.L3
.L1: brct %r5,.L0
slr %r2,%r2 # no last carry to return
j .Lexit
.L2: l %r6,0(%r1,%r3) # .L2 -> carry from last sub
sl %r6,0(%r1,%r4)
brc 4,.L4
slr %r6,%r0 # no carry yet, add carry from last sub
st %r6,0(%r1,%r2)
la %r1,4(0,%r1)
brc 11,.L1 # new carry ?
.L3: brct %r5,.L2
lr %r2,%r0 # return last carry
j .Lexit
.L4: slr %r6,%r0 # already a carry, add carry from last sub
st %r6,0(%r1,%r2)
la %r1,4(0,%r1)
brct %r5,.L2
lr %r2,%r0 # return last carry
.Lexit: l %r6,24(%r15) # restore register 6
br %r14
END(__mpn_sub_n)
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