diff options
Diffstat (limited to 'rts/gmp/mpn/x86/k6/diveby3.asm')
| -rw-r--r-- | rts/gmp/mpn/x86/k6/diveby3.asm | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/rts/gmp/mpn/x86/k6/diveby3.asm b/rts/gmp/mpn/x86/k6/diveby3.asm new file mode 100644 index 0000000000..ffb97bc380 --- /dev/null +++ b/rts/gmp/mpn/x86/k6/diveby3.asm @@ -0,0 +1,110 @@ +dnl AMD K6 mpn_divexact_by3 -- mpn division by 3, expecting no remainder. +dnl +dnl K6: 11.0 cycles/limb + + +dnl Copyright (C) 2000 Free Software Foundation, Inc. +dnl +dnl This file is part of the GNU MP Library. +dnl +dnl The GNU MP Library is free software; you can redistribute it and/or +dnl modify it under the terms of the GNU Lesser General Public License as +dnl published by the Free Software Foundation; either version 2.1 of the +dnl License, or (at your option) any later version. +dnl +dnl The GNU MP Library is distributed in the hope that it will be useful, +dnl but WITHOUT ANY WARRANTY; without even the implied warranty of +dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +dnl Lesser General Public License for more details. +dnl +dnl You should have received a copy of the GNU Lesser General Public +dnl License along with the GNU MP Library; see the file COPYING.LIB. If +dnl not, write to the Free Software Foundation, Inc., 59 Temple Place - +dnl Suite 330, Boston, MA 02111-1307, USA. + + +include(`../config.m4') + + +C mp_limb_t mpn_divexact_by3c (mp_ptr dst, mp_srcptr src, mp_size_t size, +C mp_limb_t carry); +C +C Using %esi in (%esi,%ecx,4) or 0(%esi,%ecx,4) addressing modes doesn't +C lead to vector decoding, unlike plain (%esi) does. + +defframe(PARAM_CARRY,16) +defframe(PARAM_SIZE, 12) +defframe(PARAM_SRC, 8) +defframe(PARAM_DST, 4) + +dnl multiplicative inverse of 3, modulo 2^32 +deflit(INVERSE_3, 0xAAAAAAAB) + + .text + ALIGN(32) + +PROLOGUE(mpn_divexact_by3c) +deflit(`FRAME',0) + + movl PARAM_SIZE, %ecx + pushl %esi defframe_pushl(SAVE_ESI) + + movl PARAM_SRC, %esi + pushl %edi defframe_pushl(SAVE_EDI) + + movl PARAM_DST, %edi + pushl %ebx defframe_pushl(SAVE_EBX) + + movl PARAM_CARRY, %ebx + leal (%esi,%ecx,4), %esi + + pushl $3 defframe_pushl(VAR_THREE) + leal (%edi,%ecx,4), %edi + + negl %ecx + + + C Need 32 alignment for claimed speed, to avoid the movl store + C opcode/modrm crossing a cache line boundary + + ALIGN(32) +L(top): + C eax scratch, low product + C ebx carry limb (0 to 3) + C ecx counter, limbs, negative + C edx scratch, high product + C esi &src[size] + C edi &dst[size] + C ebp + C + C The 0(%esi,%ecx,4) form pads so the finishup "movl %ebx, %eax" + C doesn't cross a 32 byte boundary, saving a couple of cycles + C (that's a fixed couple, not per loop). + +Zdisp( movl, 0,(%esi,%ecx,4), %eax) + subl %ebx, %eax + + setc %bl + + imull $INVERSE_3, %eax + + movl %eax, (%edi,%ecx,4) + addl $2, %ecx + + mull VAR_THREE + + addl %edx, %ebx + loop L(top) + + + movl SAVE_ESI, %esi + movl %ebx, %eax + + movl SAVE_EBX, %ebx + + movl SAVE_EDI, %edi + addl $FRAME, %esp + + ret + +EPILOGUE() |