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90 lines
2.7 KiB
ArmAsm
90 lines
2.7 KiB
ArmAsm
/* IBM POWER sub_n -- Subtract two limb vectors of equal, non-zero length.
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*
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* Copyright (C) 1992, 1994, 1995, 1996, 1999
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* Free Software Foundation, Inc.
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*
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* This file is part of GnuPG.
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*
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* GnuPG is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* GnuPG is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
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* USA.
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*/
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#include "sysdep.h"
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#include "asm-syntax.h"
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/*
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# INPUT PARAMETERS
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# res_ptr r3
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# s1_ptr r4
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# s2_ptr r5
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# size r6
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*/
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.toc
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.extern mpihelp_sub_n[DS]
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.extern .mpihelp_sub_n
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.csect [PR]
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.align 2
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.globl mpihelp_sub_n
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.globl .mpihelp_sub_n
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.csect mpihelp_sub_n[DS]
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mpihelp_sub_n:
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.long .mpihelp_sub_n, TOC[tc0], 0
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.csect [PR]
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.mpihelp_sub_n:
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andil. 10,6,1 # odd or even number of limbs?
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l 8,0(4) # load least significant s1 limb
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l 0,0(5) # load least significant s2 limb
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cal 3,-4(3) # offset res_ptr, it's updated before it's used
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sri 10,6,1 # count for unrolled loop
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sf 7,0,8 # subtract least significant limbs, set cy
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mtctr 10 # copy count into CTR
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beq 0,Leven # branch if even # of limbs (# of limbs >= 2)
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# We have an odd # of limbs. Add the first limbs separately.
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cmpi 1,10,0 # is count for unrolled loop zero?
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bne 1,L1 # branch if not
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st 7,4(3)
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sfe 3,0,0 # load !cy into ...
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sfi 3,3,0 # ... return value register
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br # return
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# We added least significant limbs. Now reload the next limbs to enter loop.
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L1: lu 8,4(4) # load s1 limb and update s1_ptr
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lu 0,4(5) # load s2 limb and update s2_ptr
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stu 7,4(3)
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sfe 7,0,8 # subtract limbs, set cy
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Leven: lu 9,4(4) # load s1 limb and update s1_ptr
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lu 10,4(5) # load s2 limb and update s2_ptr
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bdz Lend # If done, skip loop
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Loop: lu 8,4(4) # load s1 limb and update s1_ptr
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lu 0,4(5) # load s2 limb and update s2_ptr
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sfe 11,10,9 # subtract previous limbs with cy, set cy
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stu 7,4(3) #
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lu 9,4(4) # load s1 limb and update s1_ptr
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lu 10,4(5) # load s2 limb and update s2_ptr
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sfe 7,0,8 # subtract previous limbs with cy, set cy
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stu 11,4(3) #
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bdn Loop # decrement CTR and loop back
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Lend: sfe 11,10,9 # subtract limbs with cy, set cy
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st 7,4(3) #
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st 11,8(3) #
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sfe 3,0,0 # load !cy into ...
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sfi 3,3,0 # ... return value register
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br
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