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/* __mpn_sub_n -- Add two limb vectors of the same length > 0 and store
sum in a third limb vector. 64 bit S/390 version.
Copyright (C) 2001 Free Software Foundation, Inc.
Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com).
This file is part of the GNU MP Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
/* INPUT PARAMETERS
%r2 = res_ptr
%r3 = s1_ptr
%r4 = s2_ptr
%r5 = size. */
#include "sysdep.h"
#include "asm-syntax.h"
ENTRY(__mpn_sub_n)
stg %r6,48(%r15) # save register 6
sgr %r1,%r1
lghi %r0,1 # cannot use ahi to add carry, use slr
.L0: lg %r6,0(%r1,%r3) # .L0 -> no carry from last sub
slg %r6,0(%r1,%r4)
stg %r6,0(%r1,%r2)
la %r1,8(%r1)
brc 4,.L3
.L1: brct %r5,.L0
slgr %r2,%r2 # no last carry to return
j .Lexit
.L2: lg %r6,0(%r1,%r3) # .L2 -> carry from last sub
slg %r6,0(%r1,%r4)
brc 4,.L4
slgr %r6,%r0 # no carry yet, add carry from last sub
stg %r6,0(%r1,%r2)
la %r1,8(%r1)
brc 11,.L1 # new carry ?
.L3: brct %r5,.L2
lgr %r2,%r0 # return last carry
j .Lexit
.L4: slgr %r6,%r0 # already a carry, add carry from last sub
stg %r6,0(%r1,%r2)
la %r1,8(%r1)
brct %r5,.L2
lgr %r2,%r0 # return last carry
.Lexit: lg %r6,48(%r15) # restore register 6
br %r14
END(__mpn_sub_n)
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