1dnl AMD64 mpn_rshift -- mpn right shift, optimised for Atom. 2 3dnl Contributed to the GNU project by Torbjorn Granlund. 4 5dnl Copyright 2011, 2012 Free Software Foundation, Inc. 6 7dnl This file is part of the GNU MP Library. 8dnl 9dnl The GNU MP Library is free software; you can redistribute it and/or modify 10dnl it under the terms of either: 11dnl 12dnl * the GNU Lesser General Public License as published by the Free 13dnl Software Foundation; either version 3 of the License, or (at your 14dnl option) any later version. 15dnl 16dnl or 17dnl 18dnl * the GNU General Public License as published by the Free Software 19dnl Foundation; either version 2 of the License, or (at your option) any 20dnl later version. 21dnl 22dnl or both in parallel, as here. 23dnl 24dnl The GNU MP Library is distributed in the hope that it will be useful, but 25dnl WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 26dnl or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 27dnl for more details. 28dnl 29dnl You should have received copies of the GNU General Public License and the 30dnl GNU Lesser General Public License along with the GNU MP Library. If not, 31dnl see https://www.gnu.org/licenses/. 32 33include(`../config.m4') 34 35C cycles/limb 36C AMD K8,K9 ? 37C AMD K10 ? 38C Intel P4 ? 39C Intel core2 ? 40C Intel NHM ? 41C Intel SBR ? 42C Intel atom 4.5 43C VIA nano ? 44 45C TODO 46C * Consider using 4-way unrolling. We reach 4 c/l, but the code is 2.5 times 47C larger. 48 49C INPUT PARAMETERS 50define(`rp', `%rdi') 51define(`up', `%rsi') 52define(`n', `%rdx') 53define(`cnt', `%rcx') 54 55ABI_SUPPORT(DOS64) 56ABI_SUPPORT(STD64) 57 58ASM_START() 59 TEXT 60 ALIGN(16) 61PROLOGUE(mpn_rshift) 62 FUNC_ENTRY(4) 63 shr R32(n) 64 mov (up), %rax 65 jnc L(evn) 66 67 mov %rax, %r11 68 shr R8(cnt), %r11 69 neg R8(cnt) 70 shl R8(cnt), %rax 71 test n, n 72 jnz L(gt1) 73 mov %r11, (rp) 74 FUNC_EXIT() 75 ret 76 77L(gt1): mov 8(up), %r8 78 mov %r8, %r10 79 shl R8(cnt), %r8 80 jmp L(lo1) 81 82L(evn): mov %rax, %r10 83 neg R8(cnt) 84 shl R8(cnt), %rax 85 mov 8(up), %r9 86 mov %r9, %r11 87 shl R8(cnt), %r9 88 neg R8(cnt) 89 dec n 90 lea -8(rp), rp 91 lea 8(up), up 92 jz L(end) 93 94 ALIGN(8) 95L(top): shr R8(cnt), %r10 96 or %r10, %r9 97 shr R8(cnt), %r11 98 neg R8(cnt) 99 mov 8(up), %r8 100 mov %r8, %r10 101 mov %r9, 8(rp) 102 shl R8(cnt), %r8 103 lea 16(rp), rp 104L(lo1): mov 16(up), %r9 105 or %r11, %r8 106 mov %r9, %r11 107 shl R8(cnt), %r9 108 lea 16(up), up 109 neg R8(cnt) 110 mov %r8, (rp) 111 dec n 112 jg L(top) 113 114L(end): shr R8(cnt), %r10 115 or %r10, %r9 116 shr R8(cnt), %r11 117 mov %r9, 8(rp) 118 mov %r11, 16(rp) 119 FUNC_EXIT() 120 ret 121EPILOGUE() 122