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dnl IBM POWER mpn_rshift -- Shift a number right.
dnl Copyright 1992, 1994, 1999, 2000, 2001 Free Software Foundation, Inc.
dnl This file is part of the GNU MP Library.
dnl The GNU MP Library is free software; you can redistribute it and/or modify
dnl it under the terms of the GNU Lesser General Public License as published
dnl by the Free Software Foundation; either version 3 of the License, or (at
dnl your option) any later version.
dnl The GNU MP Library is distributed in the hope that it will be useful, but
dnl WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
dnl or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
dnl License for more details.
dnl You should have received a copy of the GNU Lesser General Public License
dnl along with the GNU MP Library. If not, see http://www.gnu.org/licenses/.
dnl INPUT PARAMETERS
dnl res_ptr r3
dnl s_ptr r4
dnl size r5
dnl cnt r6
include(`../config.m4')
ASM_START()
PROLOGUE(mpn_rshift)
sfi 8,6,32
mtctr 5 C put limb count in CTR loop register
l 0,0(4) C read least significant limb
ai 9,3,-4 C adjust res_ptr since it's offset in the stu:s
sle 3,0,8 C compute carry limb, and init MQ register
bdz Lend2 C if just one limb, skip loop
lu 0,4(4) C read 2:nd least significant limb
sleq 7,0,8 C compute least significant limb of result
bdz Lend C if just two limb, skip loop
Loop: lu 0,4(4) C load next higher limb
stu 7,4(9) C store previous result during read latency
sleq 7,0,8 C compute result limb
bdn Loop C loop back until CTR is zero
Lend: stu 7,4(9) C store 2:nd most significant limb
Lend2: sre 7,0,6 C compute most significant limb
st 7,4(9) C store it
br
EPILOGUE(mpn_rshift)
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