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/* PowerPC-32 submul_1 -- Multiply a limb vector with a limb and subtract
* the result from a second limb vector.
*
* Copyright (C) 1995, 1998 Free Software Foundation, Inc.
*
* This file is part of GnuPG.
*
* GnuPG is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* GnuPG 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
/*******************
* mpi_limb_t
* mpihelp_submul_1( mpi_ptr_t res_ptr, (r3)
* mpi_ptr_t s1_ptr, (r4)
* mpi_size_t s1_size, (r5)
* mpi_limb_t s2_limb) (r6)
*
* This is a fairly straightforward implementation. The timing of the PC601
* is hard to understand, so I will wait to optimize this until I have some
* hardware to play with.
*
* The code trivially generalizes to 64 bit limbs for the PC620.
*/
.toc
.csect .mpihelp_submul_1[PR]
.align 2
.globl mpihelp_submul_1
.globl .mpihelp_submul_1
.csect mpihelp_submul_1[DS]
mpihelp_submul_1:
.long .mpihelp_submul_1[PR], TOC[tc0], 0
.csect .mpihelp_submul_1[PR]
.mpihelp_submul_1:
mtctr 5
lwz 0,0(4)
mullw 7,0,6
mulhwu 10,0,6
lwz 9,0(3)
subfc 8,7,9
addc 7,7,8 # invert cy (r7 is junk)
addi 3,3,-4
bdz Lend
Loop: lwzu 0,4(4)
stwu 8,4(3)
mullw 8,0,6
adde 7,8,10
mulhwu 10,0,6
lwz 9,4(3)
addze 10,10
subfc 8,7,9
addc 7,7,8 # invert cy (r7 is junk)
bdnz Loop
Lend: stw 8,4(3)
addze 3,10
blr
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