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authorRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
committerRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
commit28f540f45bbacd939bfd07f213bcad2bf730b1bf (patch)
tree15f07c4c43d635959c6afee96bde71fb1b3614ee /sysdeps/i386/lshift.S
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diff --git a/sysdeps/i386/lshift.S b/sysdeps/i386/lshift.S
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+/* i80386 __mpn_lshift --
+
+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_lshift)
+C_SYMBOL_NAME(__mpn_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