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diff --git a/src/common/crc32c_ppc_fast_zero_asm.S b/src/common/crc32c_ppc_fast_zero_asm.S
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+/*
+ * Use the fixed point version of Barrett reduction to compute a mod n
+ * over GF(2) for given n using POWER8 instructions. We use k = 32.
+ *
+ * http://en.wikipedia.org/wiki/Barrett_reduction
+ *
+ * Copyright (C) 2015 Anton Blanchard <anton@au.ibm.com>, IBM
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of either:
+ *
+ * a) the GNU General Public License as published by the Free Software
+ * Foundation; either version 2 of the License, or (at your option)
+ * any later version, or
+ * b) the Apache License, Version 2.0
+ */
+#include <ppc-asm.h>
+#include "common/ppc-opcode.h"
+
+#undef toc
+
+#ifndef r1
+#define r1 1
+#endif
+
+#ifndef r2
+#define r2 2
+#endif
+
+ .section .data
+.balign 16
+
+.barrett_fz_constants:
+ /* Barrett constant m - (4^32)/n */
+ .octa 0x0000000000000000000000011f91caf6 /* x^64 div p(x) */
+ /* Barrett constant n */
+ .octa 0x0000000000000000000000011edc6f41
+
+.text
+/* unsigned int barrett_reduction(unsigned long val) */
+FUNC_START(barrett_reduction)
+ addis r4,r2,.barrett_fz_constants@toc@ha
+ addi r4,r4,.barrett_fz_constants@toc@l
+
+ li r5,16
+ vxor v1,v1,v1 /* zero v1 */
+
+ /* Get a into v0 */
+ MTVRD(v0, r3)
+ vsldoi v0,v1,v0,8 /* shift into bottom 64 bits, this is a */
+
+ /* Load constants */
+ lvx v2,0,r4 /* m */
+ lvx v3,r5,r4 /* n */
+
+ /*
+ * Now for the actual algorithm. The idea is to calculate q,
+ * the multiple of our polynomial that we need to subtract. By
+ * doing the computation 2x bits higher (ie 64 bits) and shifting the
+ * result back down 2x bits, we round down to the nearest multiple.
+ */
+ VPMSUMD(v4,v0,v2) /* ma */
+ vsldoi v4,v1,v4,8 /* q = floor(ma/(2^64)) */
+ VPMSUMD(v4,v4,v3) /* qn */
+ vxor v0,v0,v4 /* a - qn, subtraction is xor in GF(2) */
+
+ /*
+ * Get the result into r3. We need to shift it left 8 bytes:
+ * V0 [ 0 1 2 X ]
+ * V0 [ 0 X 2 3 ]
+ */
+ vsldoi v0,v0,v1,8 /* shift result into top 64 bits of v0 */
+ MFVRD(r3, v0)
+
+ blr
+FUNC_END(barrett_reduction)
+