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Faster arm64 implementation that does not use PMULL instruction (#140) 

* Faster arm64 implementation that does not use PMULL instruction
* Add NEON version for sliceXor
master
Frank Wessels 2020-05-13 01:24:22 -07:00 committed by GitHub
parent 2df03bd4d1
commit d5afb5f48e
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2 changed files with 94 additions and 99 deletions
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22
galois_arm64.go
View File

@ -8,10 +8,13 @@
package reedsolomon
//go:noescape
func galMulNEON(c uint64, in, out []byte)
func galMulNEON(low, high, in, out []byte)
//go:noescape
func galMulXorNEON(c uint64, in, out []byte)
func galMulXorNEON(low, high, in, out []byte)
//go:noescape
func galXorNEON(in, out []byte)
func galMulSlice(c byte, in, out []byte, o *options) {
if c == 1 {
@ -19,7 +22,7 @@ func galMulSlice(c byte, in, out []byte, o *options) {
return
}
var done int
galMulNEON(uint64(c), in, out)
galMulNEON(mulTableLow[c][:], mulTableHigh[c][:], in, out)
done = (len(in) >> 5) << 5
remain := len(in) - done
@ -37,7 +40,7 @@ func galMulSliceXor(c byte, in, out []byte, o *options) {
return
}
var done int
galMulXorNEON(uint64(c), in, out)
galMulXorNEON(mulTableLow[c][:], mulTableHigh[c][:], in, out)
done = (len(in) >> 5) << 5
remain := len(in) - done
@ -51,7 +54,14 @@ func galMulSliceXor(c byte, in, out []byte, o *options) {
// slice galois add
func sliceXor(in, out []byte, o *options) {
for n, input := range in {
out[n] ^= input
galXorNEON(in, out)
done := (len(in) >> 5) << 5
remain := len(in) - done
if remain > 0 {
for i := done; i < len(in); i++ {
out[i] ^= in[i]
}
}
}

171
galois_arm64.s
View File

@ -6,80 +6,44 @@
// Use github.com/minio/asm2plan9s on this file to assemble ARM instructions to
// the opcodes of their Plan9 equivalents
// polynomial multiplication
#define POLYNOMIAL_MULTIPLICATION \
WORD $0x0e3ce340 \ // pmull v0.8h,v26.8b,v28.8b
WORD $0x4e3ce346 \ // pmull2 v6.8h,v26.16b,v28.16b
WORD $0x0e3ce36c \ // pmull v12.8h,v27.8b,v28.8b
WORD $0x4e3ce372 // pmull2 v18.8h,v27.16b,v28.16b
// first reduction
#define FIRST_REDUCTION \
WORD $0x0f088402 \ // shrn v2.8b, v0.8h, #8
WORD $0x0f0884c8 \ // shrn v8.8b, v6.8h, #8
WORD $0x0f08858e \ // shrn v14.8b, v12.8h, #8
WORD $0x0f088654 \ // shrn v20.8b, v18.8h, #8
WORD $0x0e22e3c3 \ // pmull v3.8h,v30.8b,v2.8b
WORD $0x0e28e3c9 \ // pmull v9.8h,v30.8b,v8.8b
WORD $0x0e2ee3cf \ // pmull v15.8h,v30.8b,v14.8b
WORD $0x0e34e3d5 \ // pmull v21.8h,v30.8b,v20.8b
WORD $0x6e201c60 \ // eor v0.16b,v3.16b,v0.16b
WORD $0x6e261d26 \ // eor v6.16b,v9.16b,v6.16b
WORD $0x6e2c1dec \ // eor v12.16b,v15.16b,v12.16b
WORD $0x6e321eb2 // eor v18.16b,v21.16b,v18.16b
// second reduction
#define SECOND_REDUCTION \
WORD $0x0f088404 \ // shrn v4.8b, v0.8h, #8
WORD $0x0f0884ca \ // shrn v10.8b, v6.8h, #8
WORD $0x0f088590 \ // shrn v16.8b, v12.8h, #8
WORD $0x0f088656 \ // shrn v22.8b, v18.8h, #8
WORD $0x6e241c44 \ // eor v4.16b,v2.16b,v4.16b
WORD $0x6e2a1d0a \ // eor v10.16b,v8.16b,v10.16b
WORD $0x6e301dd0 \ // eor v16.16b,v14.16b,v16.16b
WORD $0x6e361e96 \ // eor v22.16b,v20.16b,v22.16b
WORD $0x0e24e3c5 \ // pmull v5.8h,v30.8b,v4.8b
WORD $0x0e2ae3cb \ // pmull v11.8h,v30.8b,v10.8b
WORD $0x0e30e3d1 \ // pmull v17.8h,v30.8b,v16.8b
WORD $0x0e36e3d7 \ // pmull v23.8h,v30.8b,v22.8b
WORD $0x6e201ca0 \ // eor v0.16b,v5.16b,v0.16b
WORD $0x6e261d61 \ // eor v1.16b,v11.16b,v6.16b
WORD $0x6e2c1e22 \ // eor v2.16b,v17.16b,v12.16b
WORD $0x6e321ee3 // eor v3.16b,v23.16b,v18.16b
// func galMulNEON(c uint64, in, out []byte)
// func galMulNEON(low, high, in, out []byte)
TEXT ·galMulNEON(SB), 7, $0
MOVD c+0(FP), R0
MOVD in_base+8(FP), R1
MOVD in_len+16(FP), R2 // length of message
MOVD out_base+32(FP), R5
MOVD in_base+48(FP), R1
MOVD in_len+56(FP), R2 // length of message
MOVD out_base+72(FP), R5
SUBS $32, R2
BMI complete
// Load constants table pointer
MOVD $·constants(SB), R3
MOVD low+0(FP), R10 // R10: &low
MOVD high+24(FP), R11 // R11: &high
WORD $0x4c407146 // ld1 {v6.16b}, [x10]
WORD $0x4c407167 // ld1 {v7.16b}, [x11]
// and load constants into v30 & v31
WORD $0x4c40a07e // ld1 {v30.16b-v31.16b}, [x3]
WORD $0x4e010c1c // dup v28.16b, w0
MOVD $0x0f, R3
WORD $0x4e010c68 // dup v8.16b, w3
loop:
// Main loop
WORD $0x4cdfa83a // ld1 {v26.4s-v27.4s}, [x1], #32
WORD $0x4cdfa020 // ld1 {v0.16b-v1.16b}, [x1], #32
POLYNOMIAL_MULTIPLICATION
// Get low input and high input
WORD $0x6f0c040a // ushr v10.16b, v0.16b, #4
WORD $0x6f0c042b // ushr v11.16b, v1.16b, #4
WORD $0x4e281c00 // and v0.16b, v0.16b, v8.16b
WORD $0x4e281c21 // and v1.16b, v1.16b, v8.16b
FIRST_REDUCTION
// Mul low part and mul high part
WORD $0x4e0000c4 // tbl v4.16b, {v6.16b}, v0.16b
WORD $0x4e0a00e5 // tbl v5.16b, {v7.16b}, v10.16b
WORD $0x4e0100ce // tbl v14.16b, {v6.16b}, v1.16b
WORD $0x4e0b00ef // tbl v15.16b, {v7.16b}, v11.16b
SECOND_REDUCTION
// combine results
WORD $0x4e1f2000 // tbl v0.16b,{v0.16b,v1.16b},v31.16b
WORD $0x4e1f2041 // tbl v1.16b,{v2.16b,v3.16b},v31.16b
// Combine results
WORD $0x6e251c84 // eor v4.16b, v4.16b, v5.16b
WORD $0x6e2f1dc5 // eor v5.16b, v14.16b, v15.16b
// Store result
WORD $0x4c9faca0 // st1 {v0.2d-v1.2d}, [x5], #32
WORD $0x4c9faca4 // st1 {v4.2d-v5.2d}, [x5], #32
SUBS $32, R2
BPL loop
@ -87,42 +51,48 @@ loop:
complete:
RET
// func galMulXorNEON(c uint64, in, out []byte)
// func galMulXorNEON(low, high, in, out []byte)
TEXT ·galMulXorNEON(SB), 7, $0
MOVD c+0(FP), R0
MOVD in_base+8(FP), R1
MOVD in_len+16(FP), R2 // length of message
MOVD out_base+32(FP), R5
MOVD in_base+48(FP), R1
MOVD in_len+56(FP), R2 // length of message
MOVD out_base+72(FP), R5
SUBS $32, R2
BMI completeXor
// Load constants table pointer
MOVD $·constants(SB), R3
MOVD low+0(FP), R10 // R10: &low
MOVD high+24(FP), R11 // R11: &high
WORD $0x4c407146 // ld1 {v6.16b}, [x10]
WORD $0x4c407167 // ld1 {v7.16b}, [x11]
// and load constants into v30 & v31
WORD $0x4c40a07e // ld1 {v30.16b-v31.16b}, [x3]
WORD $0x4e010c1c // dup v28.16b, w0
MOVD $0x0f, R3
WORD $0x4e010c68 // dup v8.16b, w3
loopXor:
// Main loop
WORD $0x4cdfa83a // ld1 {v26.4s-v27.4s}, [x1], #32
WORD $0x4c40a8b8 // ld1 {v24.4s-v25.4s}, [x5]
WORD $0x4cdfa020 // ld1 {v0.16b-v1.16b}, [x1], #32
WORD $0x4c40a0b4 // ld1 {v20.16b-v21.16b}, [x5]
POLYNOMIAL_MULTIPLICATION
// Get low input and high input
WORD $0x6f0c040a // ushr v10.16b, v0.16b, #4
WORD $0x6f0c042b // ushr v11.16b, v1.16b, #4
WORD $0x4e281c00 // and v0.16b, v0.16b, v8.16b
WORD $0x4e281c21 // and v1.16b, v1.16b, v8.16b
FIRST_REDUCTION
// Mul low part and mul high part
WORD $0x4e0000c4 // tbl v4.16b, {v6.16b}, v0.16b
WORD $0x4e0a00e5 // tbl v5.16b, {v7.16b}, v10.16b
WORD $0x4e0100ce // tbl v14.16b, {v6.16b}, v1.16b
WORD $0x4e0b00ef // tbl v15.16b, {v7.16b}, v11.16b
SECOND_REDUCTION
// Combine results
WORD $0x6e251c84 // eor v4.16b, v4.16b, v5.16b
WORD $0x6e2f1dc5 // eor v5.16b, v14.16b, v15.16b
WORD $0x6e341c84 // eor v4.16b, v4.16b, v20.16b
WORD $0x6e351ca5 // eor v5.16b, v5.16b, v21.16b
// combine results
WORD $0x4e1f2000 // tbl v0.16b,{v0.16b,v1.16b},v31.16b
WORD $0x4e1f2041 // tbl v1.16b,{v2.16b,v3.16b},v31.16b
// Xor result and store
WORD $0x6e381c00 // eor v0.16b,v0.16b,v24.16b
WORD $0x6e391c21 // eor v1.16b,v1.16b,v25.16b
WORD $0x4c9faca0 // st1 {v0.2d-v1.2d}, [x5], #32
// Store result
WORD $0x4c9faca4 // st1 {v4.2d-v5.2d}, [x5], #32
SUBS $32, R2
BPL loopXor
@ -130,12 +100,27 @@ loopXor:
completeXor:
RET
// Constants table
// generating polynomial is 29 (= 0x1d)
DATA ·constants+0x0(SB)/8, $0x1d1d1d1d1d1d1d1d
DATA ·constants+0x8(SB)/8, $0x1d1d1d1d1d1d1d1d
// constant for TBL instruction
DATA ·constants+0x10(SB)/8, $0x0e0c0a0806040200
DATA ·constants+0x18(SB)/8, $0x1e1c1a1816141210
// func galXorNEON(in, out []byte)
TEXT ·galXorNEON(SB), 7, $0
MOVD in_base+0(FP), R1
MOVD in_len+8(FP), R2 // length of message
MOVD out_base+24(FP), R5
SUBS $32, R2
BMI completeXor
GLOBL ·constants(SB), 8, $32
loopXor:
// Main loop
WORD $0x4cdfa020 // ld1 {v0.16b-v1.16b}, [x1], #32
WORD $0x4c40a0b4 // ld1 {v20.16b-v21.16b}, [x5]
WORD $0x6e341c04 // eor v4.16b, v0.16b, v20.16b
WORD $0x6e351c25 // eor v5.16b, v1.16b, v21.16b
// Store result
WORD $0x4c9faca4 // st1 {v4.2d-v5.2d}, [x5], #32
SUBS $32, R2
BPL loopXor
completeXor:
RET