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dnl PowerPC-32 mpn_sub_n -- Subtract two limb vectors of the same length > 0
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dnl and store difference in a third limb vector.
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dnl Copyright 1995, 1997, 2000 Free Software Foundation, Inc.
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dnl This file is part of the GNU MP Library.
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dnl The GNU MP Library is free software; you can redistribute it and/or modify
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dnl it under the terms of the GNU Lesser General Public License as published by
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dnl the Free Software Foundation; either version 2.1 of the License, or (at your
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dnl option) any later version.
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dnl The GNU MP Library is distributed in the hope that it will be useful, but
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dnl WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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dnl or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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dnl License for more details.
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dnl You should have received a copy of the GNU Lesser General Public License
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dnl along with the GNU MP Library; see the file COPYING.LIB. If not, write to
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dnl the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
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dnl MA 02111-1307, USA.
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include(`../config.m4')
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mtctr r6 C copy size into CTR
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addic r0,r6,-1 C set cy
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lwz r8,0(r4) C load least significant s1 limb
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lwz r0,0(r5) C load least significant s2 limb
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addi r3,r3,-4 C offset res_ptr, it's updated before it's used
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bdz .Lend C If done, skip loop
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.Loop: lwz r9,4(r4) C load s1 limb
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lwz r10,4(r5) C load s2 limb
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subfe r7,r0,r8 C subtract limbs with cy, set cy
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stw r7,4(r3) C store result limb
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bdz .Lexit C decrement CTR and exit if done
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lwzu r8,8(r4) C load s1 limb and update s1_ptr
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lwzu r0,8(r5) C load s2 limb and update s2_ptr
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subfe r7,r10,r9 C subtract limbs with cy, set cy
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stwu r7,8(r3) C store result limb and update res_ptr
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bdnz .Loop C decrement CTR and loop back
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stw r7,4(r3) C store ultimate result limb
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subfe r3,r0,r0 C load !cy into ...
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subfic r3,r3,0 C ... return value register
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.Lexit: subfe r7,r10,r9
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subfe r3,r0,r0 C load !cy into ...
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subfic r3,r3,0 C ... return value register