| dnl x86 mpn_rshift -- mpn right shift. |
| |
| dnl Copyright 1992, 1994, 1996, 1999-2002 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 cycles/limb |
| C P54 7.5 |
| C P55 7.0 |
| C P6 2.5 |
| C K6 4.5 |
| C K7 5.0 |
| C P4 16.5 |
| |
| |
| C mp_limb_t mpn_rshift (mp_ptr dst, mp_srcptr src, mp_size_t size, |
| C unsigned shift); |
| |
| defframe(PARAM_SHIFT,16) |
| defframe(PARAM_SIZE, 12) |
| defframe(PARAM_SRC, 8) |
| defframe(PARAM_DST, 4) |
| |
| TEXT |
| ALIGN(8) |
| PROLOGUE(mpn_rshift) |
| |
| pushl %edi |
| pushl %esi |
| pushl %ebx |
| deflit(`FRAME',12) |
| |
| movl PARAM_DST,%edi |
| movl PARAM_SRC,%esi |
| movl PARAM_SIZE,%edx |
| movl PARAM_SHIFT,%ecx |
| |
| leal -4(%edi,%edx,4),%edi |
| leal (%esi,%edx,4),%esi |
| negl %edx |
| |
| movl (%esi,%edx,4),%ebx C read least significant limb |
| xorl %eax,%eax |
| shrdl( %cl, %ebx, %eax) C compute carry limb |
| incl %edx |
| jz L(end) |
| pushl %eax C push carry limb onto stack |
| testb $1,%dl |
| jnz L(1) C enter loop in the middle |
| movl %ebx,%eax |
| |
| ALIGN(8) |
| L(oop): movl (%esi,%edx,4),%ebx C load next higher limb |
| shrdl( %cl, %ebx, %eax) C compute result limb |
| movl %eax,(%edi,%edx,4) C store it |
| incl %edx |
| L(1): movl (%esi,%edx,4),%eax |
| shrdl( %cl, %eax, %ebx) |
| movl %ebx,(%edi,%edx,4) |
| incl %edx |
| jnz L(oop) |
| |
| shrl %cl,%eax C compute most significant limb |
| movl %eax,(%edi) C store it |
| |
| popl %eax C pop carry limb |
| |
| popl %ebx |
| popl %esi |
| popl %edi |
| ret |
| |
| L(end): shrl %cl,%ebx C compute most significant limb |
| movl %ebx,(%edi) C store it |
| |
| popl %ebx |
| popl %esi |
| popl %edi |
| ret |
| |
| EPILOGUE() |