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math/big: improve performance for AddMulVVW and mulAddVWW for ppc64x
This change adds a better implementation in asm for AddMulVVW and mulAddVWW for ppc64x, with speedups up to 1.54x. benchmark old ns/op new ns/op delta BenchmarkAddMulVVW/1-8 6.58 6.29 -4.41% BenchmarkAddMulVVW/2-8 7.43 7.25 -2.42% BenchmarkAddMulVVW/3-8 8.95 8.15 -8.94% BenchmarkAddMulVVW/4-8 10.1 9.37 -7.23% BenchmarkAddMulVVW/5-8 12.0 10.7 -10.83% BenchmarkAddMulVVW/10-8 22.1 20.1 -9.05% BenchmarkAddMulVVW/100-8 211 154 -27.01% BenchmarkAddMulVVW/1000-8 2046 1450 -29.13% BenchmarkAddMulVVW/10000-8 20407 14793 -27.51% BenchmarkAddMulVVW/100000-8 223857 145548 -34.98% benchmark old MB/s new MB/s speedup BenchmarkAddMulVVW/1-8 9719.88 10175.79 1.05x BenchmarkAddMulVVW/2-8 17233.97 17657.54 1.02x BenchmarkAddMulVVW/3-8 21446.05 23550.49 1.10x BenchmarkAddMulVVW/4-8 25375.70 27334.33 1.08x BenchmarkAddMulVVW/5-8 26650.52 30029.34 1.13x BenchmarkAddMulVVW/10-8 28984.29 31833.68 1.10x BenchmarkAddMulVVW/100-8 30249.41 41531.69 1.37x BenchmarkAddMulVVW/1000-8 31273.35 44108.54 1.41x BenchmarkAddMulVVW/10000-8 31360.47 43263.54 1.38x BenchmarkAddMulVVW/100000-8 28589.58 43971.66 1.54x Change-Id: I8a8105d4da3592afdef3125757a99f378a0254bb Reviewed-on: https://go-review.googlesource.com/53931 Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
This commit is contained in:
Carlos Eduardo Seo
Lynn Boger
parent
92cfd07a6c
commit
3cb41be817
@ -98,103 +98,59 @@ TEXT ·shrVU(SB), NOSPLIT, $0
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// func mulAddVWW(z, x []Word, y, r Word) (c Word)
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TEXT ·mulAddVWW(SB), NOSPLIT, $0
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MOVD z+0(FP), R10
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MOVD x+24(FP), R8
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MOVD y+48(FP), R9
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MOVD r+56(FP), R4 // c = r
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MOVD z_len+8(FP), R11
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MOVD $0, R3 // i = 0
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MOVD $8, R18
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MOVD $1, R19
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MOVD z+0(FP), R10 // R10 = z[]
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MOVD x+24(FP), R8 // R8 = x[]
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MOVD y+48(FP), R9 // R9 = y
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MOVD r+56(FP), R4 // R4 = r = c
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MOVD z_len+8(FP), R11 // R11 = z_len
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JMP e5
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MOVD R0, R3 // R3 will be the index register
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CMP R0, R11
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MOVD R11, CTR // Initialize loop counter
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BEQ done
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l5:
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MULLD R18, R3, R5
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MOVD (R8)(R5), R20
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MULLD R9, R20, R6
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MULHDU R9, R20, R7
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ADDC R4, R6
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loop:
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MOVD (R8)(R3), R20 // x[i]
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MULLD R9, R20, R6 // R6 = z0 = Low-order(x[i]*y)
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MULHDU R9, R20, R7 // R7 = z1 = High-order(x[i]*y)
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ADDC R4, R6 // Compute sum for z1 and z0
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ADDZE R7
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MOVD R6, (R10)(R5)
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MOVD R7, R4
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ADD R19, R3
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e5:
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CMP R3, R11
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BLT l5
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MOVD R6, (R10)(R3) // z[i]
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MOVD R7, R4 // c
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ADD $8, R3
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BC 16, 0, loop // bdnz
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done:
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MOVD R4, c+64(FP)
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RET
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// func addMulVVW(z, x []Word, y Word) (c Word)
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TEXT ·addMulVVW(SB), NOSPLIT, $0
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MOVD z+0(FP), R10
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MOVD x+24(FP), R8
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MOVD y+48(FP), R9
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MOVD z_len+8(FP), R22
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MOVD z+0(FP), R10 // R10 = z[]
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MOVD x+24(FP), R8 // R8 = x[]
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MOVD y+48(FP), R9 // R9 = y
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MOVD z_len+8(FP), R22 // R22 = z_len
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MOVD $0, R5 // i = 0
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MOVD $0, R4 // c = 0
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MOVD $8, R28
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MOVD $-2, R23
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AND R22, R23 // mask the last bit of z.len
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MOVD $2, R24
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CMP R23, R24
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BGE unrolled
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JMP end
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unrolled:
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MOVD $8, R19 // no (RA)(RB*8) on power
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MULLD R5, R19
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MOVD (R10)(R19), R11 // R11 = z[i]
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MOVD (R8)(R19), R16 // R16 = x[i]
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ADD R28, R19, R25
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MOVD (R10)(R25), R17
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MOVD (R8)(R25), R18
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MULLD R9, R16, R12
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MULHDU R9, R16, R14
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MULLD R9, R18, R6
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MULHDU R9, R18, R7
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ADDC R4, R12
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ADDZE R14
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ADDC R11, R12 // z[i] = (x[i]*y) + z[i] + carry
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ADDZE R14 // carry = high order bits + add carry
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MOVD R12, (R10)(R19)
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ADDC R14, R6
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ADDZE R7
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ADDC R17, R6
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ADDZE R7
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MOVD R6, (R10)(R25)
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MOVD R7, R4
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ADD R24, R5
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CMP R5, R23
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BLT unrolled
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JMP end
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MOVD R0, R3 // R3 will be the index register
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CMP R0, R22
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MOVD R0, R4 // R4 = c = 0
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MOVD R22, CTR // Initialize loop counter
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BEQ done
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loop:
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MOVD $8, R19
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MULLD R5, R19
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MOVD (R10)(R19), R11
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MOVD (R8)(R19), R16
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MULLD R9, R16, R12
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MULHDU R9, R16, R14
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ADDC R4, R12
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ADDZE R14
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ADDC R11, R12
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ADDZE R14
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MOVD R12, (R10)(R19)
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MOVD R14, R4
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MOVD $1, R15
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ADD R15, R5
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end:
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CMP R5, R22
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BLT loop
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MOVD (R8)(R3), R20 // Load x[i]
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MOVD (R10)(R3), R21 // Load z[i]
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MULLD R9, R20, R6 // R6 = Low-order(x[i]*y)
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MULHDU R9, R20, R7 // R7 = High-order(x[i]*y)
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ADDC R21, R6 // R6 = z0
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ADDZE R7 // R7 = z1
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ADDC R4, R6 // R6 = z0 + c + 0
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ADDZE R7, R4 // c += z1
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MOVD R6, (R10)(R3) // Store z[i]
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ADD $8, R3
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BC 16, 0, loop // bdnz
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done:
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MOVD R4, c+56(FP)
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RET
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