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# IBM POWER __mpn_sub_n -- Subtract two limb vectors of the same length > 0 and
# store difference in a third limb vector.
# Copyright (C) 1992, 1994 Free Software Foundation, Inc.
# 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 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 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 Library General Public
# License for more details.
# You should have received a copy of the GNU Library General Public License
# along with the GNU MP Library; see the file COPYING.LIB. If not, write to
# the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
# INPUT PARAMETERS
# res_ptr r3
# s1_ptr r4
# s2_ptr r5
# size r6
.toc
.extern __mpn_sub_n[DS]
.extern .__mpn_sub_n
.csect [PR]
.align 2
.globl __mpn_sub_n
.globl .__mpn_sub_n
.csect __mpn_sub_n[DS]
__mpn_sub_n:
.long .__mpn_sub_n, TOC[tc0], 0
.csect [PR]
.__mpn_sub_n:
mtctr 6 # copy size into CTR
l 8,0(4) # load least significant s1 limb
l 0,0(5) # load least significant s2 limb
cal 3,-4(3) # offset res_ptr, it's updated before used
sf 7,0,8 # add least significant limbs, set cy
bdz Lend # If done, skip loop
Loop: lu 8,4(4) # load s1 limb and update s1_ptr
lu 0,4(5) # load s2 limb and update s2_ptr
stu 7,4(3) # store previous limb in load latency slot
sfe 7,0,8 # add new limbs with cy, set cy
bdn Loop # decrement CTR and loop back
Lend: st 7,4(3) # store ultimate result limb
sfe 3,0,0 # load !cy into ...
sfi 3,3,0 # ... return value register
br
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