diff options
| author | Lynn Boger <laboger@linux.vnet.ibm.com> | 2024-04-15 16:13:57 -0500 |
|---|---|---|
| committer | Lynn Boger <laboger@linux.vnet.ibm.com> | 2024-04-16 17:59:58 +0000 |
| commit | 330bc950933edad89abf6d1eedbfea378cf9fdf6 (patch) | |
| tree | 7cf56401fe24d9422703b2b65b80d0685fd2e11d /src/math | |
| parent | 7a0e2db135daef2c0aeb98d5e3019807a71a7b4d (diff) | |
| download | go-330bc950933edad89abf6d1eedbfea378cf9fdf6.tar.xz | |
math/big: improve use of addze in mulAddVWW on ppc64x
Improve the use of addze to avoid unnecessary register
moves on ppc64x.
goos: linux
goarch: ppc64le
pkg: math/big
cpu: POWER10
│ old.out │ new.out │
│ sec/op │ sec/op vs base │
MulAddVWW/1 4.524n ± 3% 4.248n ± 0% -6.10% (p=0.002 n=6)
MulAddVWW/2 5.634n ± 0% 5.283n ± 0% -6.24% (p=0.002 n=6)
MulAddVWW/3 6.406n ± 0% 5.918n ± 0% -7.63% (p=0.002 n=6)
MulAddVWW/4 6.484n ± 0% 5.859n ± 0% -9.64% (p=0.002 n=6)
MulAddVWW/5 7.363n ± 0% 6.766n ± 0% -8.11% (p=0.002 n=6)
MulAddVWW/10 10.920n ± 0% 9.856n ± 0% -9.75% (p=0.002 n=6)
MulAddVWW/100 83.46n ± 0% 66.95n ± 0% -19.78% (p=0.002 n=6)
MulAddVWW/1000 856.0n ± 0% 681.6n ± 0% -20.38% (p=0.002 n=6)
MulAddVWW/10000 8.589µ ± 1% 6.774µ ± 0% -21.14% (p=0.002 n=6)
MulAddVWW/100000 86.22µ ± 0% 67.71µ ± 43% -21.48% (p=0.065 n=6)
geomean 73.34n 63.62n -13.26%
Change-Id: I95d6ac49ff6b64aa678e6896f57af9d85c923aad
Reviewed-on: https://go-review.googlesource.com/c/go/+/579235
Reviewed-by: Carlos Amedee <carlos@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Paul Murphy <murp@ibm.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Diffstat (limited to 'src/math')
| -rw-r--r-- | src/math/big/arith_ppc64x.s | 21 |
1 files changed, 7 insertions, 14 deletions
diff --git a/src/math/big/arith_ppc64x.s b/src/math/big/arith_ppc64x.s index c483e252ab..330bc7e46c 100644 --- a/src/math/big/arith_ppc64x.s +++ b/src/math/big/arith_ppc64x.s @@ -514,9 +514,8 @@ TEXT ·mulAddVWW(SB), NOSPLIT, $0 MULLD R9, R20, R6 // R6 = z0 = Low-order(x[i]*y) MULHDU R9, R20, R7 // R7 = z1 = High-order(x[i]*y) ADDC R4, R6 // R6 = z0 + r - ADDZE R7 // R7 = z1 + CA + ADDZE R7, R4 // R4 = z1 + CA CMP R0, R11 - MOVD R7, R4 // R4 = c MOVD R6, 0(R10) // z[i] BEQ done @@ -536,20 +535,17 @@ loop: MULLD R9, R20, R24 // R24 = z0[i] MULHDU R9, R20, R20 // R20 = z1[i] ADDC R4, R24 // R24 = z0[i] + c - ADDZE R20 // R7 = z1[i] + CA MULLD R9, R21, R25 MULHDU R9, R21, R21 - ADDC R20, R25 - ADDZE R21 + ADDE R20, R25 MULLD R9, R22, R26 MULHDU R9, R22, R22 MULLD R9, R23, R27 MULHDU R9, R23, R23 - ADDC R21, R26 - ADDZE R22 + ADDE R21, R26 MOVD R24, 8(R10) // z[i] MOVD R25, 16(R10) // z[i+1] - ADDC R22, R27 + ADDE R22, R27 ADDZE R23,R4 // update carry MOVD R26, 24(R10) // z[i+2] MOVDU R27, 32(R10) // z[i+3] @@ -567,10 +563,9 @@ tail: MULHDU R9, R20, R25 // R25 = z1[i] ADD $-1, R11 // R11 = z_len - 1 ADDC R4, R24 - ADDZE R25 + ADDZE R25, R4 MOVDU R24, 8(R10) // z[i] CMP R0, R11 - MOVD R25, R4 // R4 = c BEQ done // If R11 = 0, we are done MOVDU 8(R8), R20 @@ -578,10 +573,9 @@ tail: MULHDU R9, R20, R25 ADD $-1, R11 ADDC R4, R24 - ADDZE R25 + ADDZE R25, R4 MOVDU R24, 8(R10) CMP R0, R11 - MOVD R25, R4 BEQ done MOVD 8(R8), R20 @@ -589,9 +583,8 @@ tail: MULHDU R9, R20, R25 ADD $-1, R11 ADDC R4, R24 - ADDZE R25 + ADDZE R25,R4 MOVD R24, 8(R10) - MOVD R25, R4 done: MOVD R4, c+64(FP) |