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Diffstat (limited to 'mpn/x86/pentium/rshift.S')
| -rw-r--r-- | mpn/x86/pentium/rshift.S | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/mpn/x86/pentium/rshift.S b/mpn/x86/pentium/rshift.S new file mode 100644 index 000000000..38398edb1 --- /dev/null +++ b/mpn/x86/pentium/rshift.S @@ -0,0 +1,217 @@ +/* Pentium optimized __mpn_rshift -- + +Copyright (C) 1992, 1994, 1995 Free Software Foundation, Inc. + +This file is part of the GNU MP Library. + +The GNU MP Library is free software; you can redistribute it and/or modify +it under the terms of the GNU Library General Public License as published by +the Free Software Foundation; either version 2 of the License, or (at your +option) any later version. + +The GNU MP Library is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY +or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public +License for more details. + +You should have received a copy of the GNU Library General Public License +along with the GNU MP Library; see the file COPYING.LIB. If not, write to +the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, +MA 02111-1307, USA. */ + +/* + INPUT PARAMETERS + res_ptr (sp + 4) + s_ptr (sp + 8) + size (sp + 12) + cnt (sp + 16) +*/ + +#include "sysdep.h" +#include "asm-syntax.h" + +.text + ALIGN (3) + .globl C_SYMBOL_NAME(__mpn_rshift) +C_SYMBOL_NAME(__mpn_rshift:) + pushl %edi + pushl %esi + pushl %ebx + pushl %ebp + + movl 20(%esp),%edi /* res_ptr */ + movl 24(%esp),%esi /* s_ptr */ + movl 28(%esp),%ebp /* size */ + movl 32(%esp),%ecx /* cnt */ + +/* We can use faster code for shift-by-1 under certain conditions. */ + cmp $1,%ecx + jne Lnormal + leal 4(%edi),%eax + cmpl %esi,%eax + jnc Lspecial /* jump if res_ptr + 1 >= s_ptr */ + leal (%edi,%ebp,4),%eax + cmpl %eax,%esi + jnc Lspecial /* jump if s_ptr >= res_ptr + size */ + +Lnormal: + movl (%esi),%edx + addl $4,%esi + xorl %eax,%eax + shrdl %cl,%edx,%eax /* compute carry limb */ + pushl %eax /* push carry limb onto stack */ + + decl %ebp + pushl %ebp + shrl $3,%ebp + jz Lend + + movl (%edi),%eax /* fetch destination cache line */ + + ALIGN (2) +Loop: movl 28(%edi),%eax /* fetch destination cache line */ + movl %edx,%ebx + + movl (%esi),%eax + movl 4(%esi),%edx + shrdl %cl,%eax,%ebx + shrdl %cl,%edx,%eax + movl %ebx,(%edi) + movl %eax,4(%edi) + + movl 8(%esi),%ebx + movl 12(%esi),%eax + shrdl %cl,%ebx,%edx + shrdl %cl,%eax,%ebx + movl %edx,8(%edi) + movl %ebx,12(%edi) + + movl 16(%esi),%edx + movl 20(%esi),%ebx + shrdl %cl,%edx,%eax + shrdl %cl,%ebx,%edx + movl %eax,16(%edi) + movl %edx,20(%edi) + + movl 24(%esi),%eax + movl 28(%esi),%edx + shrdl %cl,%eax,%ebx + shrdl %cl,%edx,%eax + movl %ebx,24(%edi) + movl %eax,28(%edi) + + addl $32,%esi + addl $32,%edi + decl %ebp + jnz Loop + +Lend: popl %ebp + andl $7,%ebp + jz Lend2 +Loop2: movl (%esi),%eax + shrdl %cl,%eax,%edx /* compute result limb */ + movl %edx,(%edi) + movl %eax,%edx + addl $4,%esi + addl $4,%edi + decl %ebp + jnz Loop2 + +Lend2: shrl %cl,%edx /* compute most significant limb */ + movl %edx,(%edi) /* store it */ + + popl %eax /* pop carry limb */ + + popl %ebp + popl %ebx + popl %esi + popl %edi + ret + +/* We loop from least significant end of the arrays, which is only + permissable if the source and destination don't overlap, since the + function is documented to work for overlapping source and destination. +*/ + +Lspecial: + leal -4(%edi,%ebp,4),%edi + leal -4(%esi,%ebp,4),%esi + + movl (%esi),%edx + subl $4,%esi + + decl %ebp + pushl %ebp + shrl $3,%ebp + + shrl $1,%edx + incl %ebp + decl %ebp + jz LLend + + movl (%edi),%eax /* fetch destination cache line */ + + ALIGN (2) +LLoop: movl -28(%edi),%eax /* fetch destination cache line */ + movl %edx,%ebx + + movl (%esi),%eax + movl -4(%esi),%edx + rcrl $1,%eax + movl %ebx,(%edi) + rcrl $1,%edx + movl %eax,-4(%edi) + + movl -8(%esi),%ebx + movl -12(%esi),%eax + rcrl $1,%ebx + movl %edx,-8(%edi) + rcrl $1,%eax + movl %ebx,-12(%edi) + + movl -16(%esi),%edx + movl -20(%esi),%ebx + rcrl $1,%edx + movl %eax,-16(%edi) + rcrl $1,%ebx + movl %edx,-20(%edi) + + movl -24(%esi),%eax + movl -28(%esi),%edx + rcrl $1,%eax + movl %ebx,-24(%edi) + rcrl $1,%edx + movl %eax,-28(%edi) + + leal -32(%esi),%esi /* use leal not to clobber carry */ + leal -32(%edi),%edi + decl %ebp + jnz LLoop + +LLend: popl %ebp + sbbl %eax,%eax /* save carry in %eax */ + andl $7,%ebp + jz LLend2 + addl %eax,%eax /* restore carry from eax */ +LLoop2: movl %edx,%ebx + movl (%esi),%edx + rcrl $1,%edx + movl %ebx,(%edi) + + leal -4(%esi),%esi /* use leal not to clobber carry */ + leal -4(%edi),%edi + decl %ebp + jnz LLoop2 + + jmp LL1 +LLend2: addl %eax,%eax /* restore carry from eax */ +LL1: movl %edx,(%edi) /* store last limb */ + + movl $0,%eax + rcrl $1,%eax + + popl %ebp + popl %ebx + popl %esi + popl %edi + ret |