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+/* IBM POWER mul_1 -- Multiply a limb vector with a limb and store
+ * the result in a second limb vector.
+ *
+ * Copyright (C) 1992, 1994, 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
+# size r5
+# s2_limb r6
+
+# The RS/6000 has no unsigned 32x32->64 bit multiplication instruction. To
+# obtain that operation, we have to use the 32x32->64 signed multiplication
+# instruction, and add the appropriate compensation to the high limb of the
+# result. We add the multiplicand if the multiplier has its most significant
+# bit set, and we add the multiplier if the multiplicand has its most
+# significant bit set. We need to preserve the carry flag between each
+# iteration, so we have to compute the compensation carefully (the natural,
+# srai+and doesn't work). Since the POWER architecture has a branch unit
+# we can branch in zero cycles, so that's how we perform the additions.
+ */
+
+ .toc
+ .csect ._gcry_mpih_mul_1[PR]
+ .align 2
+ .globl _gcry_mpih_mul_1
+ .globl ._gcry_mpih_mul_1
+ .csect _gcry_mpih_mul_1[DS]
+_gcry_mpih_mul_1:
+ .long ._gcry_mpih_mul_1[PR], TOC[tc0], 0
+ .csect ._gcry_mpih_mul_1[PR]
+._gcry_mpih_mul_1:
+
+ cal 3,-4(3)
+ l 0,0(4)
+ cmpi 0,6,0
+ mtctr 5
+ mul 9,0,6
+ srai 7,0,31
+ and 7,7,6
+ mfmq 8
+ ai 0,0,0 # reset carry
+ cax 9,9,7
+ blt Lneg
+Lpos: bdz Lend
+Lploop: lu 0,4(4)
+ stu 8,4(3)
+ cmpi 0,0,0
+ mul 10,0,6
+ mfmq 0
+ ae 8,0,9
+ bge Lp0
+ cax 10,10,6 # adjust high limb for negative limb from s1
+Lp0: bdz Lend0
+ lu 0,4(4)
+ stu 8,4(3)
+ cmpi 0,0,0
+ mul 9,0,6
+ mfmq 0
+ ae 8,0,10
+ bge Lp1
+ cax 9,9,6 # adjust high limb for negative limb from s1
+Lp1: bdn Lploop
+ b Lend
+
+Lneg: cax 9,9,0
+ bdz Lend
+Lnloop: lu 0,4(4)
+ stu 8,4(3)
+ cmpi 0,0,0
+ mul 10,0,6
+ cax 10,10,0 # adjust high limb for negative s2_limb
+ mfmq 0
+ ae 8,0,9
+ bge Ln0
+ cax 10,10,6 # adjust high limb for negative limb from s1
+Ln0: bdz Lend0
+ lu 0,4(4)
+ stu 8,4(3)
+ cmpi 0,0,0
+ mul 9,0,6
+ cax 9,9,0 # adjust high limb for negative s2_limb
+ mfmq 0
+ ae 8,0,10
+ bge Ln1
+ cax 9,9,6 # adjust high limb for negative limb from s1
+Ln1: bdn Lnloop
+ b Lend
+
+Lend0: cal 9,0(10)
+Lend: st 8,4(3)
+ aze 3,9
+ br
+