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-rw-r--r--arch/powerpc/crypto/crc32-vpmsum_core.S751
1 files changed, 751 insertions, 0 deletions
diff --git a/arch/powerpc/crypto/crc32-vpmsum_core.S b/arch/powerpc/crypto/crc32-vpmsum_core.S
new file mode 100644
index 000000000..a16a717c8
--- /dev/null
+++ b/arch/powerpc/crypto/crc32-vpmsum_core.S
@@ -0,0 +1,751 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Core of the accelerated CRC algorithm.
+ * In your file, define the constants and CRC_FUNCTION_NAME
+ * Then include this file.
+ *
+ * Calculate the checksum of data that is 16 byte aligned and a multiple of
+ * 16 bytes.
+ *
+ * The first step is to reduce it to 1024 bits. We do this in 8 parallel
+ * chunks in order to mask the latency of the vpmsum instructions. If we
+ * have more than 32 kB of data to checksum we repeat this step multiple
+ * times, passing in the previous 1024 bits.
+ *
+ * The next step is to reduce the 1024 bits to 64 bits. This step adds
+ * 32 bits of 0s to the end - this matches what a CRC does. We just
+ * calculate constants that land the data in this 32 bits.
+ *
+ * We then use fixed point Barrett reduction to compute a mod n over GF(2)
+ * for n = CRC using POWER8 instructions. We use x = 32.
+ *
+ * https://en.wikipedia.org/wiki/Barrett_reduction
+ *
+ * Copyright (C) 2015 Anton Blanchard <anton@au.ibm.com>, IBM
+*/
+
+#include <asm/ppc_asm.h>
+#include <asm/ppc-opcode.h>
+
+#define MAX_SIZE 32768
+
+ .text
+
+#if defined(__BIG_ENDIAN__) && defined(REFLECT)
+#define BYTESWAP_DATA
+#elif defined(__LITTLE_ENDIAN__) && !defined(REFLECT)
+#define BYTESWAP_DATA
+#else
+#undef BYTESWAP_DATA
+#endif
+
+#define off16 r25
+#define off32 r26
+#define off48 r27
+#define off64 r28
+#define off80 r29
+#define off96 r30
+#define off112 r31
+
+#define const1 v24
+#define const2 v25
+
+#define byteswap v26
+#define mask_32bit v27
+#define mask_64bit v28
+#define zeroes v29
+
+#ifdef BYTESWAP_DATA
+#define VPERM(A, B, C, D) vperm A, B, C, D
+#else
+#define VPERM(A, B, C, D)
+#endif
+
+/* unsigned int CRC_FUNCTION_NAME(unsigned int crc, void *p, unsigned long len) */
+FUNC_START(CRC_FUNCTION_NAME)
+ std r31,-8(r1)
+ std r30,-16(r1)
+ std r29,-24(r1)
+ std r28,-32(r1)
+ std r27,-40(r1)
+ std r26,-48(r1)
+ std r25,-56(r1)
+
+ li off16,16
+ li off32,32
+ li off48,48
+ li off64,64
+ li off80,80
+ li off96,96
+ li off112,112
+ li r0,0
+
+ /* Enough room for saving 10 non volatile VMX registers */
+ subi r6,r1,56+10*16
+ subi r7,r1,56+2*16
+
+ stvx v20,0,r6
+ stvx v21,off16,r6
+ stvx v22,off32,r6
+ stvx v23,off48,r6
+ stvx v24,off64,r6
+ stvx v25,off80,r6
+ stvx v26,off96,r6
+ stvx v27,off112,r6
+ stvx v28,0,r7
+ stvx v29,off16,r7
+
+ mr r10,r3
+
+ vxor zeroes,zeroes,zeroes
+ vspltisw v0,-1
+
+ vsldoi mask_32bit,zeroes,v0,4
+ vsldoi mask_64bit,zeroes,v0,8
+
+ /* Get the initial value into v8 */
+ vxor v8,v8,v8
+ MTVRD(v8, R3)
+#ifdef REFLECT
+ vsldoi v8,zeroes,v8,8 /* shift into bottom 32 bits */
+#else
+ vsldoi v8,v8,zeroes,4 /* shift into top 32 bits */
+#endif
+
+#ifdef BYTESWAP_DATA
+ addis r3,r2,.byteswap_constant@toc@ha
+ addi r3,r3,.byteswap_constant@toc@l
+
+ lvx byteswap,0,r3
+ addi r3,r3,16
+#endif
+
+ cmpdi r5,256
+ blt .Lshort
+
+ rldicr r6,r5,0,56
+
+ /* Checksum in blocks of MAX_SIZE */
+1: lis r7,MAX_SIZE@h
+ ori r7,r7,MAX_SIZE@l
+ mr r9,r7
+ cmpd r6,r7
+ bgt 2f
+ mr r7,r6
+2: subf r6,r7,r6
+
+ /* our main loop does 128 bytes at a time */
+ srdi r7,r7,7
+
+ /*
+ * Work out the offset into the constants table to start at. Each
+ * constant is 16 bytes, and it is used against 128 bytes of input
+ * data - 128 / 16 = 8
+ */
+ sldi r8,r7,4
+ srdi r9,r9,3
+ subf r8,r8,r9
+
+ /* We reduce our final 128 bytes in a separate step */
+ addi r7,r7,-1
+ mtctr r7
+
+ addis r3,r2,.constants@toc@ha
+ addi r3,r3,.constants@toc@l
+
+ /* Find the start of our constants */
+ add r3,r3,r8
+
+ /* zero v0-v7 which will contain our checksums */
+ vxor v0,v0,v0
+ vxor v1,v1,v1
+ vxor v2,v2,v2
+ vxor v3,v3,v3
+ vxor v4,v4,v4
+ vxor v5,v5,v5
+ vxor v6,v6,v6
+ vxor v7,v7,v7
+
+ lvx const1,0,r3
+
+ /*
+ * If we are looping back to consume more data we use the values
+ * already in v16-v23.
+ */
+ cmpdi r0,1
+ beq 2f
+
+ /* First warm up pass */
+ lvx v16,0,r4
+ lvx v17,off16,r4
+ VPERM(v16,v16,v16,byteswap)
+ VPERM(v17,v17,v17,byteswap)
+ lvx v18,off32,r4
+ lvx v19,off48,r4
+ VPERM(v18,v18,v18,byteswap)
+ VPERM(v19,v19,v19,byteswap)
+ lvx v20,off64,r4
+ lvx v21,off80,r4
+ VPERM(v20,v20,v20,byteswap)
+ VPERM(v21,v21,v21,byteswap)
+ lvx v22,off96,r4
+ lvx v23,off112,r4
+ VPERM(v22,v22,v22,byteswap)
+ VPERM(v23,v23,v23,byteswap)
+ addi r4,r4,8*16
+
+ /* xor in initial value */
+ vxor v16,v16,v8
+
+2: bdz .Lfirst_warm_up_done
+
+ addi r3,r3,16
+ lvx const2,0,r3
+
+ /* Second warm up pass */
+ VPMSUMD(v8,v16,const1)
+ lvx v16,0,r4
+ VPERM(v16,v16,v16,byteswap)
+ ori r2,r2,0
+
+ VPMSUMD(v9,v17,const1)
+ lvx v17,off16,r4
+ VPERM(v17,v17,v17,byteswap)
+ ori r2,r2,0
+
+ VPMSUMD(v10,v18,const1)
+ lvx v18,off32,r4
+ VPERM(v18,v18,v18,byteswap)
+ ori r2,r2,0
+
+ VPMSUMD(v11,v19,const1)
+ lvx v19,off48,r4
+ VPERM(v19,v19,v19,byteswap)
+ ori r2,r2,0
+
+ VPMSUMD(v12,v20,const1)
+ lvx v20,off64,r4
+ VPERM(v20,v20,v20,byteswap)
+ ori r2,r2,0
+
+ VPMSUMD(v13,v21,const1)
+ lvx v21,off80,r4
+ VPERM(v21,v21,v21,byteswap)
+ ori r2,r2,0
+
+ VPMSUMD(v14,v22,const1)
+ lvx v22,off96,r4
+ VPERM(v22,v22,v22,byteswap)
+ ori r2,r2,0
+
+ VPMSUMD(v15,v23,const1)
+ lvx v23,off112,r4
+ VPERM(v23,v23,v23,byteswap)
+
+ addi r4,r4,8*16
+
+ bdz .Lfirst_cool_down
+
+ /*
+ * main loop. We modulo schedule it such that it takes three iterations
+ * to complete - first iteration load, second iteration vpmsum, third
+ * iteration xor.
+ */
+ .balign 16
+4: lvx const1,0,r3
+ addi r3,r3,16
+ ori r2,r2,0
+
+ vxor v0,v0,v8
+ VPMSUMD(v8,v16,const2)
+ lvx v16,0,r4
+ VPERM(v16,v16,v16,byteswap)
+ ori r2,r2,0
+
+ vxor v1,v1,v9
+ VPMSUMD(v9,v17,const2)
+ lvx v17,off16,r4
+ VPERM(v17,v17,v17,byteswap)
+ ori r2,r2,0
+
+ vxor v2,v2,v10
+ VPMSUMD(v10,v18,const2)
+ lvx v18,off32,r4
+ VPERM(v18,v18,v18,byteswap)
+ ori r2,r2,0
+
+ vxor v3,v3,v11
+ VPMSUMD(v11,v19,const2)
+ lvx v19,off48,r4
+ VPERM(v19,v19,v19,byteswap)
+ lvx const2,0,r3
+ ori r2,r2,0
+
+ vxor v4,v4,v12
+ VPMSUMD(v12,v20,const1)
+ lvx v20,off64,r4
+ VPERM(v20,v20,v20,byteswap)
+ ori r2,r2,0
+
+ vxor v5,v5,v13
+ VPMSUMD(v13,v21,const1)
+ lvx v21,off80,r4
+ VPERM(v21,v21,v21,byteswap)
+ ori r2,r2,0
+
+ vxor v6,v6,v14
+ VPMSUMD(v14,v22,const1)
+ lvx v22,off96,r4
+ VPERM(v22,v22,v22,byteswap)
+ ori r2,r2,0
+
+ vxor v7,v7,v15
+ VPMSUMD(v15,v23,const1)
+ lvx v23,off112,r4
+ VPERM(v23,v23,v23,byteswap)
+
+ addi r4,r4,8*16
+
+ bdnz 4b
+
+.Lfirst_cool_down:
+ /* First cool down pass */
+ lvx const1,0,r3
+ addi r3,r3,16
+
+ vxor v0,v0,v8
+ VPMSUMD(v8,v16,const1)
+ ori r2,r2,0
+
+ vxor v1,v1,v9
+ VPMSUMD(v9,v17,const1)
+ ori r2,r2,0
+
+ vxor v2,v2,v10
+ VPMSUMD(v10,v18,const1)
+ ori r2,r2,0
+
+ vxor v3,v3,v11
+ VPMSUMD(v11,v19,const1)
+ ori r2,r2,0
+
+ vxor v4,v4,v12
+ VPMSUMD(v12,v20,const1)
+ ori r2,r2,0
+
+ vxor v5,v5,v13
+ VPMSUMD(v13,v21,const1)
+ ori r2,r2,0
+
+ vxor v6,v6,v14
+ VPMSUMD(v14,v22,const1)
+ ori r2,r2,0
+
+ vxor v7,v7,v15
+ VPMSUMD(v15,v23,const1)
+ ori r2,r2,0
+
+.Lsecond_cool_down:
+ /* Second cool down pass */
+ vxor v0,v0,v8
+ vxor v1,v1,v9
+ vxor v2,v2,v10
+ vxor v3,v3,v11
+ vxor v4,v4,v12
+ vxor v5,v5,v13
+ vxor v6,v6,v14
+ vxor v7,v7,v15
+
+#ifdef REFLECT
+ /*
+ * vpmsumd produces a 96 bit result in the least significant bits
+ * of the register. Since we are bit reflected we have to shift it
+ * left 32 bits so it occupies the least significant bits in the
+ * bit reflected domain.
+ */
+ vsldoi v0,v0,zeroes,4
+ vsldoi v1,v1,zeroes,4
+ vsldoi v2,v2,zeroes,4
+ vsldoi v3,v3,zeroes,4
+ vsldoi v4,v4,zeroes,4
+ vsldoi v5,v5,zeroes,4
+ vsldoi v6,v6,zeroes,4
+ vsldoi v7,v7,zeroes,4
+#endif
+
+ /* xor with last 1024 bits */
+ lvx v8,0,r4
+ lvx v9,off16,r4
+ VPERM(v8,v8,v8,byteswap)
+ VPERM(v9,v9,v9,byteswap)
+ lvx v10,off32,r4
+ lvx v11,off48,r4
+ VPERM(v10,v10,v10,byteswap)
+ VPERM(v11,v11,v11,byteswap)
+ lvx v12,off64,r4
+ lvx v13,off80,r4
+ VPERM(v12,v12,v12,byteswap)
+ VPERM(v13,v13,v13,byteswap)
+ lvx v14,off96,r4
+ lvx v15,off112,r4
+ VPERM(v14,v14,v14,byteswap)
+ VPERM(v15,v15,v15,byteswap)
+
+ addi r4,r4,8*16
+
+ vxor v16,v0,v8
+ vxor v17,v1,v9
+ vxor v18,v2,v10
+ vxor v19,v3,v11
+ vxor v20,v4,v12
+ vxor v21,v5,v13
+ vxor v22,v6,v14
+ vxor v23,v7,v15
+
+ li r0,1
+ cmpdi r6,0
+ addi r6,r6,128
+ bne 1b
+
+ /* Work out how many bytes we have left */
+ andi. r5,r5,127
+
+ /* Calculate where in the constant table we need to start */
+ subfic r6,r5,128
+ add r3,r3,r6
+
+ /* How many 16 byte chunks are in the tail */
+ srdi r7,r5,4
+ mtctr r7
+
+ /*
+ * Reduce the previously calculated 1024 bits to 64 bits, shifting
+ * 32 bits to include the trailing 32 bits of zeros
+ */
+ lvx v0,0,r3
+ lvx v1,off16,r3
+ lvx v2,off32,r3
+ lvx v3,off48,r3
+ lvx v4,off64,r3
+ lvx v5,off80,r3
+ lvx v6,off96,r3
+ lvx v7,off112,r3
+ addi r3,r3,8*16
+
+ VPMSUMW(v0,v16,v0)
+ VPMSUMW(v1,v17,v1)
+ VPMSUMW(v2,v18,v2)
+ VPMSUMW(v3,v19,v3)
+ VPMSUMW(v4,v20,v4)
+ VPMSUMW(v5,v21,v5)
+ VPMSUMW(v6,v22,v6)
+ VPMSUMW(v7,v23,v7)
+
+ /* Now reduce the tail (0 - 112 bytes) */
+ cmpdi r7,0
+ beq 1f
+
+ lvx v16,0,r4
+ lvx v17,0,r3
+ VPERM(v16,v16,v16,byteswap)
+ VPMSUMW(v16,v16,v17)
+ vxor v0,v0,v16
+ bdz 1f
+
+ lvx v16,off16,r4
+ lvx v17,off16,r3
+ VPERM(v16,v16,v16,byteswap)
+ VPMSUMW(v16,v16,v17)
+ vxor v0,v0,v16
+ bdz 1f
+
+ lvx v16,off32,r4
+ lvx v17,off32,r3
+ VPERM(v16,v16,v16,byteswap)
+ VPMSUMW(v16,v16,v17)
+ vxor v0,v0,v16
+ bdz 1f
+
+ lvx v16,off48,r4
+ lvx v17,off48,r3
+ VPERM(v16,v16,v16,byteswap)
+ VPMSUMW(v16,v16,v17)
+ vxor v0,v0,v16
+ bdz 1f
+
+ lvx v16,off64,r4
+ lvx v17,off64,r3
+ VPERM(v16,v16,v16,byteswap)
+ VPMSUMW(v16,v16,v17)
+ vxor v0,v0,v16
+ bdz 1f
+
+ lvx v16,off80,r4
+ lvx v17,off80,r3
+ VPERM(v16,v16,v16,byteswap)
+ VPMSUMW(v16,v16,v17)
+ vxor v0,v0,v16
+ bdz 1f
+
+ lvx v16,off96,r4
+ lvx v17,off96,r3
+ VPERM(v16,v16,v16,byteswap)
+ VPMSUMW(v16,v16,v17)
+ vxor v0,v0,v16
+
+ /* Now xor all the parallel chunks together */
+1: vxor v0,v0,v1
+ vxor v2,v2,v3
+ vxor v4,v4,v5
+ vxor v6,v6,v7
+
+ vxor v0,v0,v2
+ vxor v4,v4,v6
+
+ vxor v0,v0,v4
+
+.Lbarrett_reduction:
+ /* Barrett constants */
+ addis r3,r2,.barrett_constants@toc@ha
+ addi r3,r3,.barrett_constants@toc@l
+
+ lvx const1,0,r3
+ lvx const2,off16,r3
+
+ vsldoi v1,v0,v0,8
+ vxor v0,v0,v1 /* xor two 64 bit results together */
+
+#ifdef REFLECT
+ /* shift left one bit */
+ vspltisb v1,1
+ vsl v0,v0,v1
+#endif
+
+ vand v0,v0,mask_64bit
+#ifndef REFLECT
+ /*
+ * Now for the Barrett reduction 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(v1,v0,const1) /* ma */
+ vsldoi v1,zeroes,v1,8 /* q = floor(ma/(2^64)) */
+ VPMSUMD(v1,v1,const2) /* qn */
+ vxor v0,v0,v1 /* 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,zeroes,8 /* shift result into top 64 bits */
+#else
+ /*
+ * The reflected version of Barrett reduction. Instead of bit
+ * reflecting our data (which is expensive to do), we bit reflect our
+ * constants and our algorithm, which means the intermediate data in
+ * our vector registers goes from 0-63 instead of 63-0. We can reflect
+ * the algorithm because we don't carry in mod 2 arithmetic.
+ */
+ vand v1,v0,mask_32bit /* bottom 32 bits of a */
+ VPMSUMD(v1,v1,const1) /* ma */
+ vand v1,v1,mask_32bit /* bottom 32bits of ma */
+ VPMSUMD(v1,v1,const2) /* qn */
+ vxor v0,v0,v1 /* a - qn, subtraction is xor in GF(2) */
+
+ /*
+ * Since we are bit reflected, the result (ie the low 32 bits) is in
+ * the high 32 bits. We just need to shift it left 4 bytes
+ * V0 [ 0 1 X 3 ]
+ * V0 [ 0 X 2 3 ]
+ */
+ vsldoi v0,v0,zeroes,4 /* shift result into top 64 bits of */
+#endif
+
+ /* Get it into r3 */
+ MFVRD(R3, v0)
+
+.Lout:
+ subi r6,r1,56+10*16
+ subi r7,r1,56+2*16
+
+ lvx v20,0,r6
+ lvx v21,off16,r6
+ lvx v22,off32,r6
+ lvx v23,off48,r6
+ lvx v24,off64,r6
+ lvx v25,off80,r6
+ lvx v26,off96,r6
+ lvx v27,off112,r6
+ lvx v28,0,r7
+ lvx v29,off16,r7
+
+ ld r31,-8(r1)
+ ld r30,-16(r1)
+ ld r29,-24(r1)
+ ld r28,-32(r1)
+ ld r27,-40(r1)
+ ld r26,-48(r1)
+ ld r25,-56(r1)
+
+ blr
+
+.Lfirst_warm_up_done:
+ lvx const1,0,r3
+ addi r3,r3,16
+
+ VPMSUMD(v8,v16,const1)
+ VPMSUMD(v9,v17,const1)
+ VPMSUMD(v10,v18,const1)
+ VPMSUMD(v11,v19,const1)
+ VPMSUMD(v12,v20,const1)
+ VPMSUMD(v13,v21,const1)
+ VPMSUMD(v14,v22,const1)
+ VPMSUMD(v15,v23,const1)
+
+ b .Lsecond_cool_down
+
+.Lshort:
+ cmpdi r5,0
+ beq .Lzero
+
+ addis r3,r2,.short_constants@toc@ha
+ addi r3,r3,.short_constants@toc@l
+
+ /* Calculate where in the constant table we need to start */
+ subfic r6,r5,256
+ add r3,r3,r6
+
+ /* How many 16 byte chunks? */
+ srdi r7,r5,4
+ mtctr r7
+
+ vxor v19,v19,v19
+ vxor v20,v20,v20
+
+ lvx v0,0,r4
+ lvx v16,0,r3
+ VPERM(v0,v0,v16,byteswap)
+ vxor v0,v0,v8 /* xor in initial value */
+ VPMSUMW(v0,v0,v16)
+ bdz .Lv0
+
+ lvx v1,off16,r4
+ lvx v17,off16,r3
+ VPERM(v1,v1,v17,byteswap)
+ VPMSUMW(v1,v1,v17)
+ bdz .Lv1
+
+ lvx v2,off32,r4
+ lvx v16,off32,r3
+ VPERM(v2,v2,v16,byteswap)
+ VPMSUMW(v2,v2,v16)
+ bdz .Lv2
+
+ lvx v3,off48,r4
+ lvx v17,off48,r3
+ VPERM(v3,v3,v17,byteswap)
+ VPMSUMW(v3,v3,v17)
+ bdz .Lv3
+
+ lvx v4,off64,r4
+ lvx v16,off64,r3
+ VPERM(v4,v4,v16,byteswap)
+ VPMSUMW(v4,v4,v16)
+ bdz .Lv4
+
+ lvx v5,off80,r4
+ lvx v17,off80,r3
+ VPERM(v5,v5,v17,byteswap)
+ VPMSUMW(v5,v5,v17)
+ bdz .Lv5
+
+ lvx v6,off96,r4
+ lvx v16,off96,r3
+ VPERM(v6,v6,v16,byteswap)
+ VPMSUMW(v6,v6,v16)
+ bdz .Lv6
+
+ lvx v7,off112,r4
+ lvx v17,off112,r3
+ VPERM(v7,v7,v17,byteswap)
+ VPMSUMW(v7,v7,v17)
+ bdz .Lv7
+
+ addi r3,r3,128
+ addi r4,r4,128
+
+ lvx v8,0,r4
+ lvx v16,0,r3
+ VPERM(v8,v8,v16,byteswap)
+ VPMSUMW(v8,v8,v16)
+ bdz .Lv8
+
+ lvx v9,off16,r4
+ lvx v17,off16,r3
+ VPERM(v9,v9,v17,byteswap)
+ VPMSUMW(v9,v9,v17)
+ bdz .Lv9
+
+ lvx v10,off32,r4
+ lvx v16,off32,r3
+ VPERM(v10,v10,v16,byteswap)
+ VPMSUMW(v10,v10,v16)
+ bdz .Lv10
+
+ lvx v11,off48,r4
+ lvx v17,off48,r3
+ VPERM(v11,v11,v17,byteswap)
+ VPMSUMW(v11,v11,v17)
+ bdz .Lv11
+
+ lvx v12,off64,r4
+ lvx v16,off64,r3
+ VPERM(v12,v12,v16,byteswap)
+ VPMSUMW(v12,v12,v16)
+ bdz .Lv12
+
+ lvx v13,off80,r4
+ lvx v17,off80,r3
+ VPERM(v13,v13,v17,byteswap)
+ VPMSUMW(v13,v13,v17)
+ bdz .Lv13
+
+ lvx v14,off96,r4
+ lvx v16,off96,r3
+ VPERM(v14,v14,v16,byteswap)
+ VPMSUMW(v14,v14,v16)
+ bdz .Lv14
+
+ lvx v15,off112,r4
+ lvx v17,off112,r3
+ VPERM(v15,v15,v17,byteswap)
+ VPMSUMW(v15,v15,v17)
+
+.Lv15: vxor v19,v19,v15
+.Lv14: vxor v20,v20,v14
+.Lv13: vxor v19,v19,v13
+.Lv12: vxor v20,v20,v12
+.Lv11: vxor v19,v19,v11
+.Lv10: vxor v20,v20,v10
+.Lv9: vxor v19,v19,v9
+.Lv8: vxor v20,v20,v8
+.Lv7: vxor v19,v19,v7
+.Lv6: vxor v20,v20,v6
+.Lv5: vxor v19,v19,v5
+.Lv4: vxor v20,v20,v4
+.Lv3: vxor v19,v19,v3
+.Lv2: vxor v20,v20,v2
+.Lv1: vxor v19,v19,v1
+.Lv0: vxor v20,v20,v0
+
+ vxor v0,v19,v20
+
+ b .Lbarrett_reduction
+
+.Lzero:
+ mr r3,r10
+ b .Lout
+
+FUNC_END(CRC_FUNCTION_NAME)