diff options
author | Thomas Voss <mail@thomasvoss.com> | 2024-06-21 23:36:36 +0200 |
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committer | Thomas Voss <mail@thomasvoss.com> | 2024-06-21 23:42:26 +0200 |
commit | a89a14ef5da44684a16b204e7a70460cc8c4922a (patch) | |
tree | b23b4c6b155977909ef508fdae2f48d33d802813 /vendor/gmp-6.3.0/mpn/alpha/ev67/gcd_11.asm | |
parent | 1db63fcedab0b288820d66e100b1877b1a5a8851 (diff) |
Basic constant folding implementation
Diffstat (limited to 'vendor/gmp-6.3.0/mpn/alpha/ev67/gcd_11.asm')
-rw-r--r-- | vendor/gmp-6.3.0/mpn/alpha/ev67/gcd_11.asm | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/vendor/gmp-6.3.0/mpn/alpha/ev67/gcd_11.asm b/vendor/gmp-6.3.0/mpn/alpha/ev67/gcd_11.asm new file mode 100644 index 0000000..03c234b --- /dev/null +++ b/vendor/gmp-6.3.0/mpn/alpha/ev67/gcd_11.asm @@ -0,0 +1,79 @@ +dnl Alpha ev67 mpn_gcd_11 -- Nx1 greatest common divisor. + +dnl Copyright 2003, 2004 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 ev67: 3.4 cycles/bitpair for 1x1 part + + +C mp_limb_t mpn_gcd_1 (mp_srcptr xp, mp_size_t xsize, mp_limb_t y); +C +C In the 1x1 part, the algorithm is to change x,y to abs(x-y),min(x,y) and +C strip trailing zeros from abs(x-y) to maintain x and y both odd. +C +C The trailing zeros are calculated from just x-y, since in twos-complement +C there's the same number of trailing zeros on d or -d. This means the cttz +C runs in parallel with abs(x-y). +C +C The loop takes 5 cycles, and at 0.68 iterations per bit for two N-bit +C operands with this algorithm gives the measured 3.4 c/l. +C +C The slottings shown are for SVR4 style systems, Unicos differs in the +C initial gp setup and the LEA. + + +ASM_START() +PROLOGUE(mpn_gcd_11) + mov r16, r0 + mov r17, r1 + + ALIGN(16) +L(top): subq r0, r1, r7 C l0 d = x - y + cmpult r0, r1, r16 C u0 test x >= y + + subq r1, r0, r4 C l0 new_x = y - x + cttz r7, r8 C U0 d twos + + cmoveq r16, r7, r4 C l0 new_x = d if x>=y + cmovne r16, r0, r1 C u0 y = x if x<y + unop C l \ force cmoveq into l0 + unop C u / + + C C cmoveq2 L0, cmovne2 U0 + + srl r4, r8, r0 C U0 x = new_x >> twos + bne r7, L(top) C U1 stop when d==0 + + +L(end): mov r1, r0 C U0 return y << common_twos + ret r31, (r26), 1 C L0 +EPILOGUE() +ASM_END() |