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Diffstat (limited to 'mpi/i386/mpih-shift.S')
| -rw-r--r-- | mpi/i386/mpih-shift.S | 160 |
1 files changed, 160 insertions, 0 deletions
diff --git a/mpi/i386/mpih-shift.S b/mpi/i386/mpih-shift.S new file mode 100644 index 00000000..09ce31a5 --- /dev/null +++ b/mpi/i386/mpih-shift.S @@ -0,0 +1,160 @@ +/* i80386 rshift, lshift + * Copyright (c) 1997 by Werner Koch (dd9jn) + * Copyright (C) 1992, 1994 Free Software Foundation, Inc. + * + * This file is part of G10. + * + * G10 is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * G10 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA + * + * Note: This code is heavily based on the GNU MP Library. + * Actually it's the same code with only minor changes in the + * way the data is stored; this is to support the abstraction + * of an optional secure memory allocation which may be used + * to avoid revealing of sensitive data due to paging etc. + * The GNU MP Library itself is published under the LGPL; + * however I decided to publish this code under the plain GPL. + */ + + +#include "sysdep.h" +#include "asm-syntax.h" + + +/******************* + * mpi_limb_t + * mpihelp_lshift( mpi_ptr_t wp, (sp + 4) + * mpi_ptr_t up, (sp + 8) + * mpi_size_t usize, (sp + 12) + * unsigned cnt) (sp + 16) + */ + +.text + ALIGN (3) + .globl C_SYMBOL_NAME(mpihelp_lshift) +C_SYMBOL_NAME(mpihelp_lshift:) + 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 */ + + subl $4,%esi /* adjust s_ptr */ + + movl (%esi,%edx,4),%ebx /* read most significant limb */ + xorl %eax,%eax + shldl %cl,%ebx,%eax /* compute carry limb */ + decl %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 lower limb */ + shldl %cl,%ebx,%eax /* compute result limb */ + movl %eax,(%edi,%edx,4) /* store it */ + decl %edx +L1: movl (%esi,%edx,4),%eax + shldl %cl,%eax,%ebx + movl %ebx,(%edi,%edx,4) + decl %edx + jnz Loop + + shll %cl,%eax /* compute least significant limb */ + movl %eax,(%edi) /* store it */ + + popl %eax /* pop carry limb */ + + popl %ebx + popl %esi + popl %edi + ret + +Lend: shll %cl,%ebx /* compute least significant limb */ + movl %ebx,(%edi) /* store it */ + + popl %ebx + popl %esi + popl %edi + ret + +/******************* + * mpi_limb_t + * mpihelp_rshift( mpi_ptr_t wp, (sp + 4) + * mpi_ptr_t up, (sp + 8) + * mpi_size_t usize, (sp + 12) + * unsigned cnt) (sp + 16) + */ + +.text + ALIGN (3) + .globl C_SYMBOL_NAME(mpihelp_rshift) +C_SYMBOL_NAME(mpihelp_rshift:) + pushl %edi + pushl %esi + pushl %ebx + + movl 16(%esp),%edi /* wp */ + movl 20(%esp),%esi /* up */ + movl 24(%esp),%edx /* usize */ + 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 Lend2 + pushl %eax /* push carry limb onto stack */ + testb $1,%edx + jnz L2 /* enter loop in the middle */ + movl %ebx,%eax + + ALIGN (3) +Loop2: 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 +L2: movl (%esi,%edx,4),%eax + shrdl %cl,%eax,%ebx + movl %ebx,(%edi,%edx,4) + incl %edx + jnz Loop2 + + shrl %cl,%eax /* compute most significant limb */ + movl %eax,(%edi) /* store it */ + + popl %eax /* pop carry limb */ + + popl %ebx + popl %esi + popl %edi + ret + +Lend2: shrl %cl,%ebx /* compute most significant limb */ + movl %ebx,(%edi) /* store it */ + + popl %ebx + popl %esi + popl %edi + ret + |