Annotation of OpenXM_contrib/gmp/mpn/power/mul_1.asm, Revision 1.1
1.1 ! ohara 1: dnl IBM POWER mpn_mul_1 -- Multiply a limb vector with a limb and store the
! 2: dnl result in a second limb vector.
! 3:
! 4: dnl Copyright 1992, 1994, 1999, 2000, 2001 Free Software Foundation, Inc.
! 5:
! 6: dnl This file is part of the GNU MP Library.
! 7:
! 8: dnl The GNU MP Library is free software; you can redistribute it and/or modify
! 9: dnl it under the terms of the GNU Lesser General Public License as published
! 10: dnl by the Free Software Foundation; either version 2.1 of the License, or (at
! 11: dnl your option) any later version.
! 12:
! 13: dnl The GNU MP Library is distributed in the hope that it will be useful, but
! 14: dnl WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
! 15: dnl or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
! 16: dnl License for more details.
! 17:
! 18: dnl You should have received a copy of the GNU Lesser General Public License
! 19: dnl along with the GNU MP Library; see the file COPYING.LIB. If not, write to
! 20: dnl the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
! 21: dnl MA 02111-1307, USA.
! 22:
! 23:
! 24: dnl INPUT PARAMETERS
! 25: dnl res_ptr r3
! 26: dnl s1_ptr r4
! 27: dnl size r5
! 28: dnl s2_limb r6
! 29:
! 30: dnl The POWER architecture has no unsigned 32x32->64 bit multiplication
! 31: dnl instruction. To obtain that operation, we have to use the 32x32->64
! 32: dnl signed multiplication instruction, and add the appropriate compensation to
! 33: dnl the high limb of the result. We add the multiplicand if the multiplier
! 34: dnl has its most significant bit set, and we add the multiplier if the
! 35: dnl multiplicand has its most significant bit set. We need to preserve the
! 36: dnl carry flag between each iteration, so we have to compute the compensation
! 37: dnl carefully (the natural, srai+and doesn't work). Since all POWER can
! 38: dnl branch in zero cycles, we use conditional branches to for the additions.
! 39:
! 40: include(`../config.m4')
! 41:
! 42: ASM_START()
! 43: PROLOGUE(mpn_mul_1)
! 44: cal 3,-4(3)
! 45: l 0,0(4)
! 46: cmpi 0,6,0
! 47: mtctr 5
! 48: mul 9,0,6
! 49: srai 7,0,31
! 50: and 7,7,6
! 51: mfmq 8
! 52: ai 0,0,0 C reset carry
! 53: cax 9,9,7
! 54: blt Lneg
! 55: Lpos: bdz Lend
! 56: Lploop: lu 0,4(4)
! 57: stu 8,4(3)
! 58: cmpi 0,0,0
! 59: mul 10,0,6
! 60: mfmq 0
! 61: ae 8,0,9
! 62: bge Lp0
! 63: cax 10,10,6 C adjust high limb for negative limb from s1
! 64: Lp0: bdz Lend0
! 65: lu 0,4(4)
! 66: stu 8,4(3)
! 67: cmpi 0,0,0
! 68: mul 9,0,6
! 69: mfmq 0
! 70: ae 8,0,10
! 71: bge Lp1
! 72: cax 9,9,6 C adjust high limb for negative limb from s1
! 73: Lp1: bdn Lploop
! 74: b Lend
! 75:
! 76: Lneg: cax 9,9,0
! 77: bdz Lend
! 78: Lnloop: lu 0,4(4)
! 79: stu 8,4(3)
! 80: cmpi 0,0,0
! 81: mul 10,0,6
! 82: cax 10,10,0 C adjust high limb for negative s2_limb
! 83: mfmq 0
! 84: ae 8,0,9
! 85: bge Ln0
! 86: cax 10,10,6 C adjust high limb for negative limb from s1
! 87: Ln0: bdz Lend0
! 88: lu 0,4(4)
! 89: stu 8,4(3)
! 90: cmpi 0,0,0
! 91: mul 9,0,6
! 92: cax 9,9,0 C adjust high limb for negative s2_limb
! 93: mfmq 0
! 94: ae 8,0,10
! 95: bge Ln1
! 96: cax 9,9,6 C adjust high limb for negative limb from s1
! 97: Ln1: bdn Lnloop
! 98: b Lend
! 99:
! 100: Lend0: cal 9,0(10)
! 101: Lend: st 8,4(3)
! 102: aze 3,9
! 103: br
! 104: EPILOGUE(mpn_mul_1)
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