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runtime: eliminate redundant load in Xchg and Xadd on arm64

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Loading arguments of Xchg(64) and Xadd(64) functions to registers
could be done only once.

Change-Id: Iaf0a695ec9c6a221dfa755855edb68c476978a5b
Reviewed-on: https://go-review.googlesource.com/c/go/+/227001
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This commit is contained in:
Xiangdong Ji 2020-03-06 08:44:23 +00:00 committed by Keith Randall
parent e18a5ba0ca
commit 3103495fa9
1 changed files with 4 additions and 4 deletions
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8
src/runtime/internal/atomic/atomic_arm64.s
View file

@ -61,9 +61,9 @@ TEXT runtime∕internal∕atomic·Store64(SB), NOSPLIT, $0-16
RET
TEXT runtime∕internal∕atomic·Xchg(SB), NOSPLIT, $0-20
again:
MOVD ptr+0(FP), R0
MOVW new+8(FP), R1
again:
LDAXRW (R0), R2
STLXRW R1, (R0), R3
CBNZ R3, again
@ -71,9 +71,9 @@ again:
RET
TEXT runtime∕internal∕atomic·Xchg64(SB), NOSPLIT, $0-24
again:
MOVD ptr+0(FP), R0
MOVD new+8(FP), R1
again:
LDAXR (R0), R2
STLXR R1, (R0), R3
CBNZ R3, again
@ -108,9 +108,9 @@ ok:
// *val += delta;
// return *val;
TEXT runtime∕internal∕atomic·Xadd(SB), NOSPLIT, $0-20
again:
MOVD ptr+0(FP), R0
MOVW delta+8(FP), R1
again:
LDAXRW (R0), R2
ADDW R2, R1, R2
STLXRW R2, (R0), R3
@ -119,9 +119,9 @@ again:
RET
TEXT runtime∕internal∕atomic·Xadd64(SB), NOSPLIT, $0-24
again:
MOVD ptr+0(FP), R0
MOVD delta+8(FP), R1
again:
LDAXR (R0), R2
ADD R2, R1, R2
STLXR R2, (R0), R3