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authorKibum Kim <kb0929.kim@samsung.com>2012-01-07 00:46:38 +0900
committerKibum Kim <kb0929.kim@samsung.com>2012-01-07 00:46:38 +0900
commitf5660c6460a863b19f9ef745575780e37cc192a9 (patch)
tree0b478679da32d706de7b0de546d2e4daf03b160c /mpi/i386/mpih-lshift.S
parent06b9124a4f9d38acc78e6af686bc49a06f6354f8 (diff)
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+/* i80386 lshift
+ * Copyright (C) 1992, 1994, 1998,
+ * 2001 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG 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.
+ *
+ * GnuPG 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
+ * 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 %ebx,%eax /* compute carry limb */
+ decl %edx
+ jz Lend
+ pushl %eax /* push carry limb onto stack */
+ testb $1,%dl
+ jnz L1 /* enter loop in the middle */
+ movl %ebx,%eax
+
+ ALIGN (3)
+Loop: movl (%esi,%edx,4),%ebx /* load next lower limb */
+ shldl %ebx,%eax /* compute result limb */
+ movl %eax,(%edi,%edx,4) /* store it */
+ decl %edx
+L1: movl (%esi,%edx,4),%eax
+ shldl %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
+