51 lines
1.8 KiB
NASM
51 lines
1.8 KiB
NASM
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dnl IBM POWER mpn_rshift -- Shift a number right.
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dnl Copyright 1992, 1994, 1999, 2000, 2001 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
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dnl by the Free Software Foundation; either version 2.1 of the License, or (at
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dnl your 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
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dnl to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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dnl Boston, MA 02110-1301, USA.
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dnl INPUT PARAMETERS
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dnl res_ptr r3
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dnl s_ptr r4
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dnl size r5
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dnl cnt r6
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include(`../config.m4')
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ASM_START()
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PROLOGUE(mpn_rshift)
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sfi 8,6,32
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mtctr 5 C put limb count in CTR loop register
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l 0,0(4) C read least significant limb
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ai 9,3,-4 C adjust res_ptr since it's offset in the stu:s
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sle 3,0,8 C compute carry limb, and init MQ register
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bdz Lend2 C if just one limb, skip loop
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lu 0,4(4) C read 2:nd least significant limb
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sleq 7,0,8 C compute least significant limb of result
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bdz Lend C if just two limb, skip loop
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Loop: lu 0,4(4) C load next higher limb
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stu 7,4(9) C store previous result during read latency
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sleq 7,0,8 C compute result limb
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bdn Loop C loop back until CTR is zero
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Lend: stu 7,4(9) C store 2:nd most significant limb
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Lend2: sre 7,0,6 C compute most significant limb
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st 7,4(9) C store it
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br
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EPILOGUE(mpn_rshift)
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