initial import

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