Import gcrypt public-key cryptography and implement signature checking.

grub-core/lib/libgcrypt/mpi/power/mpih-add1.S

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+/* IBM POWER add_n -- Add two limb vectors of equal, non-zero length.
+ *
+ *      Copyright (C) 1992, 1994, 1996, 1999,
+ *                    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
+ */
+
+#include "sysdep.h"
+#include "asm-syntax.h"
+
+/*
+# INPUT PARAMETERS
+# res_ptr	r3
+# s1_ptr	r4
+# s2_ptr	r5
+# size		r6
+ */
+
+	.toc
+	.extern _gcry_mpih_add_n[DS]
+	.extern ._gcry_mpih_add_n
+.csect [PR]
+	.align 2
+	.globl _gcry_mpih_add_n
+	.globl ._gcry_mpih_add_n
+	.csect _gcry_mpih_add_n[DS]
+_gcry_mpih_add_n:
+	.long ._gcry_mpih_add_n, TOC[tc0], 0
+	.csect [PR]
+._gcry_mpih_add_n:
+	andil.	10,6,1		# odd or even number of limbs?
+	l	8,0(4)		# load least significant s1 limb
+	l	0,0(5)		# load least significant s2 limb
+	cal	3,-4(3) 	# offset res_ptr, it's updated before it's used
+	sri	10,6,1		# count for unrolled loop
+	a	7,0,8		# add least significant limbs, set cy
+	mtctr	10		# copy count into CTR
+	beq	0,Leven 	# branch if even # of limbs (# of limbs >= 2)
+
+# We have an odd # of limbs.  Add the first limbs separately.
+	cmpi	1,10,0		# is count for unrolled loop zero?
+	bne	1,L1		# branch if not
+	st	7,4(3)
+	aze	3,10		# use the fact that r10 is zero...
+	br			# return
+
+# We added least significant limbs.  Now reload the next limbs to enter loop.
+L1:	lu	8,4(4)		# load s1 limb and update s1_ptr
+	lu	0,4(5)		# load s2 limb and update s2_ptr
+	stu	7,4(3)
+	ae	7,0,8		# add limbs, set cy
+Leven:	lu	9,4(4)		# load s1 limb and update s1_ptr
+	lu	10,4(5) 	# load s2 limb and update s2_ptr
+	bdz	Lend		# If done, skip loop
+
+Loop:	lu	8,4(4)		# load s1 limb and update s1_ptr
+	lu	0,4(5)		# load s2 limb and update s2_ptr
+	ae	11,9,10 	# add previous limbs with cy, set cy
+	stu	7,4(3)		#
+	lu	9,4(4)		# load s1 limb and update s1_ptr
+	lu	10,4(5) 	# load s2 limb and update s2_ptr
+	ae	7,0,8		# add previous limbs with cy, set cy
+	stu	11,4(3) 	#
+	bdn	Loop		# decrement CTR and loop back
+
+Lend:	ae	11,9,10 	# add limbs with cy, set cy
+	st	7,4(3)		#
+	st	11,8(3) 	#
+	lil	3,0		# load cy into ...
+	aze	3,3		# ... return value register
+	br
+