diff options
Diffstat (limited to 'sysdeps/i386/rshift.S')
| -rw-r--r-- | sysdeps/i386/rshift.S | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/sysdeps/i386/rshift.S b/sysdeps/i386/rshift.S new file mode 100644 index 0000000000..d4aa0b93e6 --- /dev/null +++ b/sysdeps/i386/rshift.S @@ -0,0 +1,86 @@ +/* i80386 __mpn_rshift -- + +Copyright (C) 1992, 1994 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., 675 Mass Ave, Cambridge, MA 02139, 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 + + movl 16(%esp),%edi /* res_ptr */ + movl 20(%esp),%esi /* s_ptr */ + movl 24(%esp),%edx /* size */ + movl 28(%esp),%ecx /* cnt */ + + leal -4(%edi,%edx,4),%edi + leal (%esi,%edx,4),%esi + negl %edx + + movl (%esi,%edx,4),%ebx /* read least significant limb */ + xorl %eax,%eax + shrdl %cl,%ebx,%eax /* compute carry limb */ + incl %edx + jz Lend + pushl %eax /* push carry limb onto stack */ + testb $1,%edx + jnz L1 /* enter loop in the middle */ + movl %ebx,%eax + + ALIGN (3) +Loop: movl (%esi,%edx,4),%ebx /* load next higher limb */ + shrdl %cl,%ebx,%eax /* compute result limb */ + movl %eax,(%edi,%edx,4) /* store it */ + incl %edx +L1: movl (%esi,%edx,4),%eax + shrdl %cl,%eax,%ebx + movl %ebx,(%edi,%edx,4) + incl %edx + jnz Loop + + shrl %cl,%eax /* compute most significant limb */ + movl %eax,(%edi) /* store it */ + + popl %eax /* pop carry limb */ + + popl %ebx + popl %esi + popl %edi + ret + +Lend: shrl %cl,%ebx /* compute most significant limb */ + movl %ebx,(%edi) /* store it */ + + popl %ebx + popl %esi + popl %edi + ret |