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-rw-r--r--sysdeps/i386/i586/rshift.S213
1 files changed, 213 insertions, 0 deletions
diff --git a/sysdeps/i386/i586/rshift.S b/sysdeps/i386/i586/rshift.S
new file mode 100644
index 0000000000..51cde8f07f
--- /dev/null
+++ b/sysdeps/i386/i586/rshift.S
@@ -0,0 +1,213 @@
+/* Pentium optimized __mpn_rshift -- 
+
+Copyright (C) 1992, 1994, 1995 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
+	pushl	%ebp
+
+	movl	20(%esp),%edi		/* res_ptr */
+	movl	24(%esp),%esi		/* s_ptr */
+	movl	28(%esp),%ebp		/* size */
+	movl	32(%esp),%ecx		/* cnt */
+
+	cmp	$1,%ecx
+	jne	Lnormal
+	movl	%edi,%eax
+	subl	%esi,%eax
+	cmpl	%ebp,%eax
+	jnc	Lspecial
+
+Lnormal:
+	movl	(%esi),%edx
+	addl	$4,%esi
+	xorl	%eax,%eax
+	shrdl	%cl,%edx,%eax		/* compute carry limb */
+	pushl	%eax			/* push carry limb onto stack */
+
+	decl	%ebp
+	pushl	%ebp
+	shrl	$3,%ebp
+	jz	Lend
+
+	movl	(%edi),%eax		/* fetch destination cache line */
+
+	ALIGN	(2)
+Loop:	movl	28(%edi),%eax		/* fetch destination cache line */
+	movl	%edx,%ebx
+
+	movl	(%esi),%eax
+	movl	4(%esi),%edx
+	shrdl	%cl,%eax,%ebx
+	shrdl	%cl,%edx,%eax
+	movl	%ebx,(%edi)
+	movl	%eax,4(%edi)
+
+	movl	8(%esi),%ebx
+	movl	12(%esi),%eax
+	shrdl	%cl,%ebx,%edx
+	shrdl	%cl,%eax,%ebx
+	movl	%edx,8(%edi)
+	movl	%ebx,12(%edi)
+
+	movl	16(%esi),%edx
+	movl	20(%esi),%ebx
+	shrdl	%cl,%edx,%eax
+	shrdl	%cl,%ebx,%edx
+	movl	%eax,16(%edi)
+	movl	%edx,20(%edi)
+
+	movl	24(%esi),%eax
+	movl	28(%esi),%edx
+	shrdl	%cl,%eax,%ebx
+	shrdl	%cl,%edx,%eax
+	movl	%ebx,24(%edi)
+	movl	%eax,28(%edi)
+
+	addl	$32,%esi
+	addl	$32,%edi
+	decl	%ebp
+	jnz	Loop
+
+Lend:	popl	%ebp
+	andl	$7,%ebp
+	jz	Lend2
+Loop2:	movl	(%esi),%eax
+	shrdl	%cl,%eax,%edx		/* compute result limb */
+	movl	%edx,(%edi)
+	movl	%eax,%edx
+	addl	$4,%esi
+	addl	$4,%edi
+	decl	%ebp
+	jnz	Loop2
+
+Lend2:	shrl	%cl,%edx		/* compute most significant limb */
+	movl	%edx,(%edi)		/* store it */
+
+	popl	%eax			/* pop carry limb */
+
+	popl	%ebp
+	popl	%ebx
+	popl	%esi
+	popl	%edi
+	ret
+
+/* We loop from least significant end of the arrays, which is only
+   permissable if the source and destination don't overlap, since the
+   function is documented to work for overlapping source and destination.
+*/
+
+Lspecial:
+	leal	-4(%edi,%ebp,4),%edi
+	leal	-4(%esi,%ebp,4),%esi
+
+	movl	(%esi),%edx
+	subl	$4,%esi
+
+	decl	%ebp
+	pushl	%ebp
+	shrl	$3,%ebp
+
+	shrl	$1,%edx
+	incl	%ebp
+	decl	%ebp
+	jz	LLend
+
+	movl	(%edi),%eax		/* fetch destination cache line */
+
+	ALIGN	(2)
+LLoop:	movl	-28(%edi),%eax		/* fetch destination cache line */
+	movl	%edx,%ebx
+
+	movl	(%esi),%eax
+	movl	-4(%esi),%edx
+	rcrl	$1,%eax
+	movl	%ebx,(%edi)
+	rcrl	$1,%edx
+	movl	%eax,-4(%edi)
+
+	movl	-8(%esi),%ebx
+	movl	-12(%esi),%eax
+	rcrl	$1,%ebx
+	movl	%edx,-8(%edi)
+	rcrl	$1,%eax
+	movl	%ebx,-12(%edi)
+
+	movl	-16(%esi),%edx
+	movl	-20(%esi),%ebx
+	rcrl	$1,%edx
+	movl	%eax,-16(%edi)
+	rcrl	$1,%ebx
+	movl	%edx,-20(%edi)
+
+	movl	-24(%esi),%eax
+	movl	-28(%esi),%edx
+	rcrl	$1,%eax
+	movl	%ebx,-24(%edi)
+	rcrl	$1,%edx
+	movl	%eax,-28(%edi)
+
+	leal	-32(%esi),%esi		/* use leal not to clobber carry */
+	leal	-32(%edi),%edi
+	decl	%ebp
+	jnz	LLoop
+
+LLend:	popl	%ebp
+	sbbl	%eax,%eax		/* save carry in %eax */
+	andl	$7,%ebp
+	jz	LLend2
+	addl	%eax,%eax		/* restore carry from eax */
+LLoop2:	movl	%edx,%ebx
+	movl	(%esi),%edx
+	rcrl	$1,%edx
+	movl	%ebx,(%edi)
+
+	leal	-4(%esi),%esi		/* use leal not to clobber carry */
+	leal	-4(%edi),%edi
+	decl	%ebp
+	jnz	LLoop2
+
+	jmp	LL1
+LLend2:	addl	%eax,%eax		/* restore carry from eax */
+LL1:	movl	%edx,(%edi)		/* store last limb */
+
+	movl	$0,%eax
+	rcrl	$1,%eax
+
+	popl	%ebp
+	popl	%ebx
+	popl	%esi
+	popl	%edi
+	ret