From 3bd8684facfadb57ba649cae6b067e3a3ecb1208 Mon Sep 17 00:00:00 2001 From: Robert Griesemer Date: Fri, 24 Aug 2012 10:51:39 -0700 Subject: [PATCH] math/big: minor tweaks to assembly code (slightly better performance) Benchmarks run on 2.8GHz Quad-Code Intel Xeon, 4GB 800MHz DDR2 FB-DIMM ("PowerMac"). benchmark old ns/op new ns/op delta BenchmarkAddVV_1 7 7 -0.82% BenchmarkAddVV_2 8 8 -3.46% BenchmarkAddVV_3 10 9 -4.81% BenchmarkAddVV_4 9 9 -1.89% BenchmarkAddVV_5 11 10 -5.22% BenchmarkAddVV_1e1 17 18 +4.05% BenchmarkAddVV_1e2 117 115 -1.71% BenchmarkAddVV_1e3 1095 1090 -0.46% BenchmarkAddVV_1e4 13149 12679 -3.57% BenchmarkAddVV_1e5 135133 129482 -4.18% BenchmarkAddVW_1 6 6 -1.14% BenchmarkAddVW_2 7 7 +3.78% BenchmarkAddVW_3 8 8 +0.12% BenchmarkAddVW_4 8 8 -6.52% BenchmarkAddVW_5 9 8 -3.70% BenchmarkAddVW_1e1 14 13 -4.29% BenchmarkAddVW_1e2 97 96 -1.33% BenchmarkAddVW_1e3 953 940 -1.36% BenchmarkAddVW_1e4 9776 9527 -2.55% BenchmarkAddVW_1e5 102396 97738 -4.55% benchmark old MB/s new MB/s speedup BenchmarkAddVV_1 8702.84 8774.56 1.01x BenchmarkAddVV_2 14739.60 15277.82 1.04x BenchmarkAddVV_3 18375.37 19398.16 1.06x BenchmarkAddVV_4 26935.44 27464.68 1.02x BenchmarkAddVV_5 27754.04 29423.30 1.06x BenchmarkAddVV_1e1 37050.89 35629.72 0.96x BenchmarkAddVV_1e2 54289.15 55533.24 1.02x BenchmarkAddVV_1e3 58428.83 58682.53 1.00x BenchmarkAddVV_1e4 48670.55 50475.99 1.04x BenchmarkAddVV_1e5 47360.54 49427.66 1.04x BenchmarkAddVW_1 10397.27 10502.23 1.01x BenchmarkAddVW_2 17279.03 16654.13 0.96x BenchmarkAddVW_3 23858.39 23825.89 1.00x BenchmarkAddVW_4 29799.42 31895.06 1.07x BenchmarkAddVW_5 34781.83 36105.11 1.04x BenchmarkAddVW_1e1 45629.88 47597.42 1.04x BenchmarkAddVW_1e2 65341.93 66240.04 1.01x BenchmarkAddVW_1e3 67153.67 68069.83 1.01x BenchmarkAddVW_1e4 65464.60 67173.83 1.03x BenchmarkAddVW_1e5 62501.88 65480.66 1.05x R=iant CC=golang-dev https://golang.org/cl/6484056 --- src/pkg/math/big/arith_amd64.s | 70 ++++++++++++++++------------------ 1 file changed, 33 insertions(+), 37 deletions(-) diff --git a/src/pkg/math/big/arith_amd64.s b/src/pkg/math/big/arith_amd64.s index 80b75ef805..b1d4a862b2 100644 --- a/src/pkg/math/big/arith_amd64.s +++ b/src/pkg/math/big/arith_amd64.s @@ -32,45 +32,44 @@ TEXT ·addVV(SB),7,$0 MOVQ z+0(FP), R10 MOVQ $0, CX // c = 0 - MOVQ $0, SI // i = 0 + MOVQ $0, SI // i = 0 // uncomment the next line to disable the unrolled loop // JMP V1 - CMPQ DI, $4 - JL V1 // if n < 4 goto V1 + SUBQ $4, DI // n -= 4 + JL V1 // if n < 0 goto V1 -U1: // n >= 4 +U1: // n >= 0 // regular loop body unrolled 4x + RCRQ $1, CX // CF = c MOVQ 0(R8)(SI*8), R11 MOVQ 8(R8)(SI*8), R12 MOVQ 16(R8)(SI*8), R13 MOVQ 24(R8)(SI*8), R14 - RCRQ $1, CX // restore CF ADCQ 0(R9)(SI*8), R11 ADCQ 8(R9)(SI*8), R12 ADCQ 16(R9)(SI*8), R13 ADCQ 24(R9)(SI*8), R14 - RCLQ $1, CX // save CF MOVQ R11, 0(R10)(SI*8) MOVQ R12, 8(R10)(SI*8) MOVQ R13, 16(R10)(SI*8) MOVQ R14, 24(R10)(SI*8) + RCLQ $1, CX // c = CF ADDQ $4, SI // i += 4 SUBQ $4, DI // n -= 4 - CMPQ DI, $4 - JGE U1 // if n >= 4 goto U1 + JGE U1 // if n >= 0 goto U1 -V1: CMPQ DI, $0 +V1: ADDQ $4, DI // n += 4 JLE E1 // if n <= 0 goto E1 L1: // n > 0 + RCRQ $1, CX // CF = c MOVQ 0(R8)(SI*8), R11 - RCRQ $1, CX // restore CF ADCQ 0(R9)(SI*8), R11 - RCLQ $1, CX // save CF MOVQ R11, 0(R10)(SI*8) + RCLQ $1, CX // c = CF ADDQ $1, SI // i++ SUBQ $1, DI // n-- @@ -94,40 +93,39 @@ TEXT ·subVV(SB),7,$0 // uncomment the next line to disable the unrolled loop // JMP V2 - CMPQ DI, $4 - JL V2 // if n < 4 goto V2 + SUBQ $4, DI // n -= 4 + JL V2 // if n < 0 goto V2 -U2: // n >= 4 +U2: // n >= 0 // regular loop body unrolled 4x + RCRQ $1, CX // CF = c MOVQ 0(R8)(SI*8), R11 MOVQ 8(R8)(SI*8), R12 MOVQ 16(R8)(SI*8), R13 MOVQ 24(R8)(SI*8), R14 - RCRQ $1, CX // restore CF SBBQ 0(R9)(SI*8), R11 SBBQ 8(R9)(SI*8), R12 SBBQ 16(R9)(SI*8), R13 SBBQ 24(R9)(SI*8), R14 - RCLQ $1, CX // save CF MOVQ R11, 0(R10)(SI*8) MOVQ R12, 8(R10)(SI*8) MOVQ R13, 16(R10)(SI*8) MOVQ R14, 24(R10)(SI*8) + RCLQ $1, CX // c = CF ADDQ $4, SI // i += 4 SUBQ $4, DI // n -= 4 - CMPQ DI, $4 - JGE U2 // if n >= 4 goto U2 + JGE U2 // if n >= 0 goto U2 -V2: CMPQ DI, $0 +V2: ADDQ $4, DI // n += 4 JLE E2 // if n <= 0 goto E2 L2: // n > 0 + RCRQ $1, CX // CF = c MOVQ 0(R8)(SI*8), R11 - RCRQ $1, CX // restore CF SBBQ 0(R9)(SI*8), R11 - RCLQ $1, CX // save CF MOVQ R11, 0(R10)(SI*8) + RCLQ $1, CX // c = CF ADDQ $1, SI // i++ SUBQ $1, DI // n-- @@ -149,10 +147,10 @@ TEXT ·addVW(SB),7,$0 // uncomment the next line to disable the unrolled loop // JMP V3 - CMPQ DI, $4 + SUBQ $4, DI // n -= 4 JL V3 // if n < 4 goto V3 -U3: // n >= 4 +U3: // n >= 0 // regular loop body unrolled 4x MOVQ 0(R8)(SI*8), R11 MOVQ 8(R8)(SI*8), R12 @@ -162,25 +160,24 @@ U3: // n >= 4 ADCQ $0, R12 ADCQ $0, R13 ADCQ $0, R14 - RCLQ $1, CX - ANDQ $1, CX MOVQ R11, 0(R10)(SI*8) MOVQ R12, 8(R10)(SI*8) MOVQ R13, 16(R10)(SI*8) MOVQ R14, 24(R10)(SI*8) + RCLQ $1, CX // c = CF + ANDQ $1, CX ADDQ $4, SI // i += 4 SUBQ $4, DI // n -= 4 - CMPQ DI, $4 - JGE U3 // if n >= 4 goto U3 + JGE U3 // if n >= 0 goto U3 -V3: CMPQ DI, $0 +V3: ADDQ $4, DI // n += 4 JLE E3 // if n <= 0 goto E3 L3: // n > 0 ADDQ 0(R8)(SI*8), CX MOVQ CX, 0(R10)(SI*8) - RCLQ $1, CX + RCLQ $1, CX // c = CF ANDQ $1, CX ADDQ $1, SI // i++ @@ -204,10 +201,10 @@ TEXT ·subVW(SB),7,$0 // uncomment the next line to disable the unrolled loop // JMP V4 - CMPQ DI, $4 + SUBQ $4, DI // n -= 4 JL V4 // if n < 4 goto V4 -U4: // n >= 4 +U4: // n >= 0 // regular loop body unrolled 4x MOVQ 0(R8)(SI*8), R11 MOVQ 8(R8)(SI*8), R12 @@ -217,26 +214,25 @@ U4: // n >= 4 SBBQ $0, R12 SBBQ $0, R13 SBBQ $0, R14 - RCLQ $1, CX - ANDQ $1, CX MOVQ R11, 0(R10)(SI*8) MOVQ R12, 8(R10)(SI*8) MOVQ R13, 16(R10)(SI*8) MOVQ R14, 24(R10)(SI*8) + RCLQ $1, CX // c = CF + ANDQ $1, CX ADDQ $4, SI // i += 4 SUBQ $4, DI // n -= 4 - CMPQ DI, $4 - JGE U4 // if n >= 4 goto U4 + JGE U4 // if n >= 0 goto U4 -V4: CMPQ DI, $0 +V4: ADDQ $4, DI // n += 4 JLE E4 // if n <= 0 goto E4 L4: // n > 0 MOVQ 0(R8)(SI*8), R11 SUBQ CX, R11 MOVQ R11, 0(R10)(SI*8) - RCLQ $1, CX + RCLQ $1, CX // c = CF ANDQ $1, CX ADDQ $1, SI // i++ -- 2.48.1