diff options
Diffstat (limited to 'gmp/mpn/x86/k6/mod_34lsub1.asm')
| -rw-r--r-- | gmp/mpn/x86/k6/mod_34lsub1.asm | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/gmp/mpn/x86/k6/mod_34lsub1.asm b/gmp/mpn/x86/k6/mod_34lsub1.asm new file mode 100644 index 0000000000..7e30503e54 --- /dev/null +++ b/gmp/mpn/x86/k6/mod_34lsub1.asm @@ -0,0 +1,190 @@ +dnl AMD K6 mpn_mod_34lsub1 -- mpn remainder modulo 2**24-1. + +dnl Copyright 2000-2002 Free Software Foundation, Inc. + +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 modify +dnl it under the terms of either: +dnl +dnl * the GNU Lesser General Public License as published by the Free +dnl Software Foundation; either version 3 of the License, or (at your +dnl option) any later version. +dnl +dnl or +dnl +dnl * the GNU General Public License as published by the Free Software +dnl Foundation; either version 2 of the License, or (at your option) any +dnl later version. +dnl +dnl or both in parallel, as here. +dnl +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 General Public License +dnl for more details. +dnl +dnl You should have received copies of the GNU General Public License and the +dnl GNU Lesser General Public License along with the GNU MP Library. If not, +dnl see https://www.gnu.org/licenses/. + +include(`../config.m4') + + +C K6: 2.66 cycles/limb + + +C mp_limb_t mpn_mod_34lsub1 (mp_srcptr src, mp_size_t size) +C +C An attempt was made to use a loop like +C +C L(top): +C adcl (%edx), %eax +C adcl 4(%edx), %ebx +C adcl 8(%edx), %esi +C leal 12(%edx), %edx +C loop L(top) +C +C with %ecx starting from floor(size/3), but it still measured 2.66 c/l. +C The form used instead can save about 6 cycles by not dividing by 3. +C +C In the code used, putting the "leal"s at the top of the loop is necessary +C for the claimed speed, anywhere else costs an extra cycle per loop. +C Perhaps a tight loop like this needs short decode instructions at the +C branch target, which would explain the leal/loop form above taking 8 +C cycles instead of 7 too. + +defframe(PARAM_SIZE, 8) +defframe(PARAM_SRC, 4) + +dnl re-use parameter space +define(SAVE_EBX, `PARAM_SIZE') +define(SAVE_ESI, `PARAM_SRC') + + TEXT + ALIGN(16) +PROLOGUE(mpn_mod_34lsub1) +deflit(`FRAME',0) + + movl PARAM_SIZE, %eax + movl PARAM_SRC, %edx + + subl $2, %eax + ja L(three_or_more) + +Zdisp( movl, 0,(%edx), %eax) C avoid code cache line boundary + jne L(one) + + movl %eax, %ecx + movl 4(%edx), %edx + + shrl $24, %eax C src[0] high + andl $0x00FFFFFF, %ecx C src[0] low + + addl %ecx, %eax + movl %edx, %ecx + + shll $8, %edx + andl $0x00FFFF00, %edx C src[1] high + + shrl $16, %ecx C src[1] low + addl %ecx, %eax + + addl %edx, %eax + +L(one): + ret + + +L(three_or_more): + C eax size-2 + C ebx + C ecx + C edx src + + movl %ebx, SAVE_EBX + xorl %ebx, %ebx + + movl %esi, SAVE_ESI + pushl %edi FRAME_pushl() + + xorl %esi, %esi + xorl %edi, %edi C and clear carry flag + +L(top): + C eax counter, limbs + C ebx acc 0mod3 + C ecx + C edx src, incrementing + C esi acc 1mod3 + C edi acc 2mod3 + C ebp + + leal -2(%eax), %eax + leal 12(%edx), %edx + + adcl -12(%edx), %ebx + adcl -8(%edx), %esi + adcl -4(%edx), %edi + + decl %eax + jg L(top) + + + C ecx is -3, -2 or -1 representing 0, 1 or 2 more limbs, respectively + + movb $0, %cl + incl %eax + + js L(combine) C 0 more + +Zdisp( adcl, 0,(%edx), %ebx) C avoid code cache line crossings + + movb $8, %cl + decl %eax + + js L(combine) C 1 more + + adcl 4(%edx), %esi + + movb $16, %cl + + +L(combine): + sbbl %edx, %edx + + shll %cl, %edx C carry + movl %ebx, %eax C 0mod3 + + shrl $24, %eax C 0mod3 high + andl $0x00FFFFFF, %ebx C 0mod3 low + + subl %edx, %eax C apply carry + movl %esi, %ecx C 1mod3 + + shrl $16, %esi C 1mod3 high + addl %ebx, %eax C apply 0mod3 low + + andl $0x0000FFFF, %ecx + addl %esi, %eax C apply 1mod3 high + + shll $8, %ecx C 1mod3 low + movl %edi, %edx C 2mod3 + + shrl $8, %edx C 2mod3 high + addl %ecx, %eax C apply 1mod3 low + + addl %edx, %eax C apply 2mod3 high + andl $0x000000FF, %edi + + shll $16, %edi C 2mod3 low + movl SAVE_EBX, %ebx + + addl %edi, %eax C apply 2mod3 low + movl SAVE_ESI, %esi + + popl %edi + + ret + +EPILOGUE() |