Import gcrypt public-key cryptography and implement signature checking.

grub-core/lib/libgcrypt/mpi/i386/mpih-rshift.S

@@ -0,0 +1,97 @@
+/* i80386   rshift
+ *
+ *      Copyright (C) 1992, 1994, 1998, 
+ *                    2001, 2002 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,	(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(_gcry_mpih_rshift)
+C_SYMBOL_NAME(_gcry_mpih_rshift:)
+	pushl	%edi
+	pushl	%esi
+	pushl	%ebx
+
+	movl	16(%esp),%edi		/* wp */
+	movl	20(%esp),%esi		/* up */
+	movl	24(%esp),%edx		/* usize */
+	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	Lend2
+	pushl	%eax			/* push carry limb onto stack */
+	testb	$1,%dl
+	jnz	L2			/* enter loop in the middle */
+	movl	%ebx,%eax
+
+	ALIGN (3)
+Loop2:	 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
+L2:	movl	(%esi,%edx,4),%eax
+	shrdl	%cl,%eax,%ebx
+	movl	%ebx,(%edi,%edx,4)
+	incl	%edx
+	jnz	Loop2
+
+	shrl	%cl,%eax		/* compute most significant limb */
+	movl	%eax,(%edi)		/* store it */
+
+	popl	%eax			/* pop carry limb */
+
+	popl	%ebx
+	popl	%esi
+	popl	%edi
+	ret
+
+Lend2:	shrl	%cl,%ebx		/* compute most significant limb */
+	movl	%ebx,(%edi)		/* store it */
+
+	popl	%ebx
+	popl	%esi
+	popl	%edi
+	ret
+