diff --git a/mpi/amd64/mpih-lshift.S b/mpi/amd64/mpih-lshift.S
index 9e8979b1..76e9408f 100644
--- a/mpi/amd64/mpih-lshift.S
+++ b/mpi/amd64/mpih-lshift.S
@@ -1,79 +1,79 @@
 /* AMD64 (x86_64) lshift -- Left shift a limb vector and store
  *		  result in a second limb vector.
  *
  *      Copyright (C) 1992, 1994, 1995, 1998, 
  *                    2001, 2002, 2006 Free Software Foundation, Inc.
  *
  * This file is part of Libgcrypt.
  *
  * Libgcrypt is free software; you can redistribute it and/or modify
  * it under the terms of the GNU Lesser General Public License as
  * published by the Free Software Foundation; either version 2.1 of
  * the License, or (at your option) any later version.
  *
  * Libgcrypt 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 Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 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.
  */
 
 
 #include "sysdep.h"
 #include "asm-syntax.h"
 
 /*******************
  * mpi_limb_t
  * _gcry_mpih_lshift( mpi_ptr_t wp,	rdi
  *		   mpi_ptr_t up,	rsi
  *		   mpi_size_t usize,	rdx
  *		   unsigned cnt)	rcx
  */
 
 .text
 	.globl C_SYMBOL_NAME(_gcry_mpih_lshift)
 C_SYMBOL_NAME(_gcry_mpih_lshift:)
 	FUNC_ENTRY()
-	movq	-8(%rsi,%rdx,8), %mm7
-	movd	%ecx, %mm1
+	/* Note: %xmm6 and %xmm7 not used for WIN64 ABI compatibility. */
+	movq	-8(%rsi,%rdx,8), %xmm4
+	movd	%ecx, %xmm1
 	movl	$64, %eax
 	subl	%ecx, %eax
-	movd	%eax, %mm0
-	movq	%mm7, %mm3
-	psrlq	%mm0, %mm7
-	movd	%mm7, %rax
+	movd	%eax, %xmm0
+	movdqa	%xmm4, %xmm3
+	psrlq	%xmm0, %xmm4
+	movd	%xmm4, %rax
 	subq	$2, %rdx
 	jl	.Lendo
 
 	ALIGN(4)			/* minimal alignment for claimed speed */
-.Loop:	movq	(%rsi,%rdx,8), %mm6
-	movq	%mm6, %mm2
-	psrlq	%mm0, %mm6
-	psllq	%mm1, %mm3
-	por	%mm6, %mm3
-	movq	%mm3, 8(%rdi,%rdx,8)
+.Loop:	movq	(%rsi,%rdx,8), %xmm5
+	movdqa	%xmm5, %xmm2
+	psrlq	%xmm0, %xmm5
+	psllq	%xmm1, %xmm3
+	por	%xmm5, %xmm3
+	movq	%xmm3, 8(%rdi,%rdx,8)
 	je	.Lende
-	movq	-8(%rsi,%rdx,8), %mm7
-	movq	%mm7, %mm3
-	psrlq	%mm0, %mm7
-	psllq	%mm1, %mm2
-	por	%mm7, %mm2
-	movq	%mm2, (%rdi,%rdx,8)
+	movq	-8(%rsi,%rdx,8), %xmm4
+	movdqa	%xmm4, %xmm3
+	psrlq	%xmm0, %xmm4
+	psllq	%xmm1, %xmm2
+	por	%xmm4, %xmm2
+	movq	%xmm2, (%rdi,%rdx,8)
 	subq	$2, %rdx
 	jge	.Loop
 
-.Lendo:	movq	%mm3, %mm2
-.Lende:	psllq	%mm1, %mm2
-	movq	%mm2, (%rdi)
-	emms
+.Lendo:	movdqa	%xmm3, %xmm2
+.Lende:	psllq	%xmm1, %xmm2
+	movq	%xmm2, (%rdi)
 	FUNC_EXIT()
 	ret
diff --git a/mpi/amd64/mpih-rshift.S b/mpi/amd64/mpih-rshift.S
index 7bd59421..d5e27974 100644
--- a/mpi/amd64/mpih-rshift.S
+++ b/mpi/amd64/mpih-rshift.S
@@ -1,82 +1,82 @@
 /* AMD64 (x86_64) rshift -- Right shift a limb vector and store
  *		  result in a second limb vector.
  *
  *      Copyright (C) 1992, 1994, 1995, 1998, 
  *                    2001, 2002, 2006 Free Software Foundation, Inc.
  *
  * This file is part of Libgcrypt.
  *
  * Libgcrypt is free software; you can redistribute it and/or modify
  * it under the terms of the GNU Lesser General Public License as
  * published by the Free Software Foundation; either version 2.1 of
  * the License, or (at your option) any later version.
  *
  * Libgcrypt 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 Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 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.
  */
 
 
 #include "sysdep.h"
 #include "asm-syntax.h"
 
 /*******************
  * mpi_limb_t
  * _gcry_mpih_rshift( mpi_ptr_t wp,	rdi
  *		   mpi_ptr_t up,	rsi
  *		   mpi_size_t usize,	rdx
  *		   unsigned cnt)	rcx
  */
 
 .text
 	.globl C_SYMBOL_NAME(_gcry_mpih_rshift)
 C_SYMBOL_NAME(_gcry_mpih_rshift:)
 	FUNC_ENTRY()
-	movq	(%rsi), %mm7
-	movd	%ecx, %mm1
+	/* Note: %xmm6 and %xmm7 not used for WIN64 ABI compatibility. */
+	movq	(%rsi), %xmm4
+	movd	%ecx, %xmm1
 	movl	$64, %eax
 	subl	%ecx, %eax
-	movd	%eax, %mm0
-	movq	%mm7, %mm3
-	psllq	%mm0, %mm7
-	movd	%mm7, %rax
+	movd	%eax, %xmm0
+	movdqa	%xmm4, %xmm3
+	psllq	%xmm0, %xmm4
+	movd	%xmm4, %rax
 	leaq	(%rsi,%rdx,8), %rsi
 	leaq	(%rdi,%rdx,8), %rdi
 	negq	%rdx
 	addq	$2, %rdx
 	jg	.Lendo
 
 	ALIGN(4)			/* minimal alignment for claimed speed */
-.Loop:	movq	-8(%rsi,%rdx,8), %mm6
-	movq	%mm6, %mm2
-	psllq	%mm0, %mm6
-	psrlq	%mm1, %mm3
-	por	%mm6, %mm3
-	movq	%mm3, -16(%rdi,%rdx,8)
+.Loop:	movq	-8(%rsi,%rdx,8), %xmm5
+	movdqa	%xmm5, %xmm2
+	psllq	%xmm0, %xmm5
+	psrlq	%xmm1, %xmm3
+	por	%xmm5, %xmm3
+	movq	%xmm3, -16(%rdi,%rdx,8)
 	je	.Lende
-	movq	(%rsi,%rdx,8), %mm7
-	movq	%mm7, %mm3
-	psllq	%mm0, %mm7
-	psrlq	%mm1, %mm2
-	por	%mm7, %mm2
-	movq	%mm2, -8(%rdi,%rdx,8)
+	movq	(%rsi,%rdx,8), %xmm4
+	movdqa	%xmm4, %xmm3
+	psllq	%xmm0, %xmm4
+	psrlq	%xmm1, %xmm2
+	por	%xmm4, %xmm2
+	movq	%xmm2, -8(%rdi,%rdx,8)
 	addq	$2, %rdx
 	jle	.Loop
 
-.Lendo:	movq	%mm3, %mm2
-.Lende:	psrlq	%mm1, %mm2
-	movq	%mm2, -8(%rdi)
-	emms
+.Lendo:	movdqa	%xmm3, %xmm2
+.Lende:	psrlq	%xmm1, %xmm2
+	movq	%xmm2, -8(%rdi)
 	FUNC_EXIT()
 	ret