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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
This commit is contained in:
Robert Griesemer 2012-08-24 10:51:39 -07:00
parent 35422bc11f
commit 3bd8684fac

View File

@ -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++