| dnl AMD64 mpn_rshift -- mpn right shift, optimised for Atom. |
| |
| dnl Contributed to the GNU project by Torbjorn Granlund. |
| |
| dnl Copyright 2011, 2012 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 cycles/limb |
| C AMD K8,K9 ? |
| C AMD K10 ? |
| C Intel P4 ? |
| C Intel core2 ? |
| C Intel NHM ? |
| C Intel SBR ? |
| C Intel atom 4.5 |
| C VIA nano ? |
| |
| C TODO |
| C * Consider using 4-way unrolling. We reach 4 c/l, but the code is 2.5 times |
| C larger. |
| |
| C INPUT PARAMETERS |
| define(`rp', `%rdi') |
| define(`up', `%rsi') |
| define(`n', `%rdx') |
| define(`cnt', `%rcx') |
| |
| ABI_SUPPORT(DOS64) |
| ABI_SUPPORT(STD64) |
| |
| ASM_START() |
| TEXT |
| ALIGN(16) |
| PROLOGUE(mpn_rshift) |
| FUNC_ENTRY(4) |
| shr R32(n) |
| mov (up), %rax |
| jnc L(evn) |
| |
| mov %rax, %r11 |
| shr R8(cnt), %r11 |
| neg R8(cnt) |
| shl R8(cnt), %rax |
| test n, n |
| jnz L(gt1) |
| mov %r11, (rp) |
| FUNC_EXIT() |
| ret |
| |
| L(gt1): mov 8(up), %r8 |
| mov %r8, %r10 |
| shl R8(cnt), %r8 |
| jmp L(lo1) |
| |
| L(evn): mov %rax, %r10 |
| neg R8(cnt) |
| shl R8(cnt), %rax |
| mov 8(up), %r9 |
| mov %r9, %r11 |
| shl R8(cnt), %r9 |
| neg R8(cnt) |
| dec n |
| lea -8(rp), rp |
| lea 8(up), up |
| jz L(end) |
| |
| ALIGN(8) |
| L(top): shr R8(cnt), %r10 |
| or %r10, %r9 |
| shr R8(cnt), %r11 |
| neg R8(cnt) |
| mov 8(up), %r8 |
| mov %r8, %r10 |
| mov %r9, 8(rp) |
| shl R8(cnt), %r8 |
| lea 16(rp), rp |
| L(lo1): mov 16(up), %r9 |
| or %r11, %r8 |
| mov %r9, %r11 |
| shl R8(cnt), %r9 |
| lea 16(up), up |
| neg R8(cnt) |
| mov %r8, (rp) |
| dec n |
| jg L(top) |
| |
| L(end): shr R8(cnt), %r10 |
| or %r10, %r9 |
| shr R8(cnt), %r11 |
| mov %r9, 8(rp) |
| mov %r11, 16(rp) |
| FUNC_EXIT() |
| ret |
| EPILOGUE() |
