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/* i80386 sub_n -- Sub two limb vectors of the same length > 0 and store
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* sum in a third limb vector.
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* Copyright (C) 1992, 1994, 1995, 1998,
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* 2001, 2002 Free Software Foundation, Inc.
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* This file is part of GnuPG.
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* GnuPG is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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* GnuPG is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
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* Note: This code is heavily based on the GNU MP Library.
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* Actually it's the same code with only minor changes in the
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* way the data is stored; this is to support the abstraction
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* of an optional secure memory allocation which may be used
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* to avoid revealing of sensitive data due to paging etc.
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* The GNU MP Library itself is published under the LGPL;
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* however I decided to publish this code under the plain GPL.
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#include "asm-syntax.h"
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* mpihelp_sub_n( mpi_ptr_t res_ptr, (sp + 4)
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* mpi_ptr_t s1_ptr, (sp + 8)
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* mpi_ptr_t s2_ptr, (sp + 12)
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* mpi_size_t size) (sp + 16)
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.globl C_SYMBOL_NAME(mpihelp_sub_n)
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C_SYMBOL_NAME(mpihelp_sub_n:)
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movl 12(%esp),%edi /* res_ptr */
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movl 16(%esp),%esi /* s1_ptr */
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movl 20(%esp),%edx /* s2_ptr */
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movl 24(%esp),%ecx /* size */
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shrl $3,%ecx /* compute count for unrolled loop */
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andl $7,%eax /* get index where to start loop */
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jz Loop /* necessary special case for 0 */
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incl %ecx /* adjust loop count */
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shll $2,%eax /* adjustment for pointers... */
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subl %eax,%edi /* ... since they are offset ... */
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subl %eax,%esi /* ... by a constant when we ... */
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subl %eax,%edx /* ... enter the loop */
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shrl $2,%eax /* restore previous value */
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/* Calculate start address in loop for PIC. Due to limitations in some
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assemblers, Loop-L0-3 cannot be put into the leal */
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L0: leal (%eax,%eax,8),%eax
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addl $(Loop-L0-3),%eax
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/* Calculate start address in loop for non-PIC. */
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leal Loop-3(%eax,%eax,8),%eax
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jmp *%eax /* jump into loop */
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Loop: movl (%esi),%eax