1dnl ARM v8a mpn_gcd_11. 2 3dnl Based on the K7 gcd_1.asm, by Kevin Ryde. Rehacked for ARM by Torbjorn 4dnl Granlund. 5 6dnl Copyright 2000-2002, 2005, 2009, 2011-2013 Free Software Foundation, Inc. 7 8dnl This file is part of the GNU MP Library. 9dnl 10dnl The GNU MP Library is free software; you can redistribute it and/or modify 11dnl it under the terms of either: 12dnl 13dnl * the GNU Lesser General Public License as published by the Free 14dnl Software Foundation; either version 3 of the License, or (at your 15dnl option) any later version. 16dnl 17dnl or 18dnl 19dnl * the GNU General Public License as published by the Free Software 20dnl Foundation; either version 2 of the License, or (at your option) any 21dnl later version. 22dnl 23dnl or both in parallel, as here. 24dnl 25dnl The GNU MP Library is distributed in the hope that it will be useful, but 26dnl WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 27dnl or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 28dnl for more details. 29dnl 30dnl You should have received copies of the GNU General Public License and the 31dnl GNU Lesser General Public License along with the GNU MP Library. If not, 32dnl see https://www.gnu.org/licenses/. 33 34include(`../config.m4') 35 36changecom(blah) 37 38C cycles/bit (approx) 39C Cortex-A35 ? 40C Cortex-A53 ? 41C Cortex-A55 ? 42C Cortex-A57 ? 43C Cortex-A72 ? 44C Cortex-A73 ? 45C Cortex-A75 ? 46C Cortex-A76 ? 47C Cortex-A77 ? 48C Numbers measured with: speed -CD -s16-64 -t48 mpn_gcd_1 49 50define(`u0', `x0') 51define(`v0', `x1') 52 53ASM_START() 54 TEXT 55 ALIGN(16) 56PROLOGUE(mpn_gcd_11) 57 subs x3, u0, v0 C 0 58 b.eq L(end) C 59 60 ALIGN(16) 61L(top): rbit x12, x3 C 1,5 62 clz x12, x12 C 2 63 csneg x3, x3, x3, cs C v = abs(u-v), even 1 64 csel u0, v0, u0, cs C u = min(u,v) 1 65 lsr v0, x3, x12 C 3 66 subs x3, u0, v0 C 4 67 b.ne L(top) C 68 69L(end): ret 70EPILOGUE() 71