mul_1.asm
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上传日期:2022-08-06
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- dnl IBM POWER mpn_mul_1 -- Multiply a limb vector with a limb and store the
- dnl result in a second limb vector.
- 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 s1_ptr r4
- dnl size r5
- dnl s2_limb r6
- dnl The POWER architecture has no unsigned 32x32->64 bit multiplication
- dnl instruction. To obtain that operation, we have to use the 32x32->64
- dnl signed multiplication instruction, and add the appropriate compensation to
- dnl the high limb of the result. We add the multiplicand if the multiplier
- dnl has its most significant bit set, and we add the multiplier if the
- dnl multiplicand has its most significant bit set. We need to preserve the
- dnl carry flag between each iteration, so we have to compute the compensation
- dnl carefully (the natural, srai+and doesn't work). Since all POWER can
- dnl branch in zero cycles, we use conditional branches for the compensation.
- include(`../config.m4')
- ASM_START()
- PROLOGUE(mpn_mul_1)
- cal 3,-4(3)
- l 0,0(4)
- cmpi 0,6,0
- mtctr 5
- mul 9,0,6
- srai 7,0,31
- and 7,7,6
- mfmq 8
- ai 0,0,0 C reset carry
- cax 9,9,7
- blt Lneg
- Lpos: bdz Lend
- Lploop: lu 0,4(4)
- stu 8,4(3)
- cmpi 0,0,0
- mul 10,0,6
- mfmq 0
- ae 8,0,9
- bge Lp0
- cax 10,10,6 C adjust high limb for negative limb from s1
- Lp0: bdz Lend0
- lu 0,4(4)
- stu 8,4(3)
- cmpi 0,0,0
- mul 9,0,6
- mfmq 0
- ae 8,0,10
- bge Lp1
- cax 9,9,6 C adjust high limb for negative limb from s1
- Lp1: bdn Lploop
- b Lend
- Lneg: cax 9,9,0
- bdz Lend
- Lnloop: lu 0,4(4)
- stu 8,4(3)
- cmpi 0,0,0
- mul 10,0,6
- cax 10,10,0 C adjust high limb for negative s2_limb
- mfmq 0
- ae 8,0,9
- bge Ln0
- cax 10,10,6 C adjust high limb for negative limb from s1
- Ln0: bdz Lend0
- lu 0,4(4)
- stu 8,4(3)
- cmpi 0,0,0
- mul 9,0,6
- cax 9,9,0 C adjust high limb for negative s2_limb
- mfmq 0
- ae 8,0,10
- bge Ln1
- cax 9,9,6 C adjust high limb for negative limb from s1
- Ln1: bdn Lnloop
- b Lend
- Lend0: cal 9,0(10)
- Lend: st 8,4(3)
- aze 3,9
- br
- EPILOGUE(mpn_mul_1)