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author | Cherry Zhang <cherryyz@google.com> | 2020-10-28 09:12:20 -0400 |
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committer | Cherry Zhang <cherryyz@google.com> | 2020-10-28 09:12:20 -0400 |
commit | a16e30d162c1c7408db7821e7b9513cefa09c6ca (patch) | |
tree | af752ba9ba44c547df39bb0af9bff79f610ba9d5 /src/runtime/internal/atomic/atomic_ppc64x.s | |
parent | 91e4d2d57bc341dd82c98247117114c851380aef (diff) | |
parent | cf6cfba4d5358404dd890f6025e573a4b2156543 (diff) | |
download | go-dev.link.tar.gz go-dev.link.zip |
[dev.link] all: merge branch 'master' into dev.linkdev.link
Clean merge.
Change-Id: Ia7b2808bc649790198d34c226a61d9e569084dc5
Diffstat (limited to 'src/runtime/internal/atomic/atomic_ppc64x.s')
-rw-r--r-- | src/runtime/internal/atomic/atomic_ppc64x.s | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/src/runtime/internal/atomic/atomic_ppc64x.s b/src/runtime/internal/atomic/atomic_ppc64x.s index c2f696fb34..b79cdbca34 100644 --- a/src/runtime/internal/atomic/atomic_ppc64x.s +++ b/src/runtime/internal/atomic/atomic_ppc64x.s @@ -6,6 +6,15 @@ #include "textflag.h" + +// For more details about how various memory models are +// enforced on POWER, the following paper provides more +// details about how they enforce C/C++ like models. This +// gives context about why the strange looking code +// sequences below work. +// +// http://www.rdrop.com/users/paulmck/scalability/paper/N2745r.2011.03.04a.html + // uint32 runtime∕internal∕atomic·Load(uint32 volatile* ptr) TEXT ·Load(SB),NOSPLIT|NOFRAME,$-8-12 MOVD ptr+0(FP), R3 @@ -56,5 +65,16 @@ TEXT ·LoadAcq(SB),NOSPLIT|NOFRAME,$-8-12 MOVWZ 0(R3), R3 CMPW R3, R3, CR7 BC 4, 30, 1(PC) // bne- cr7, 0x4 + ISYNC MOVW R3, ret+8(FP) RET + +// uint64 runtime∕internal∕atomic·LoadAcq64(uint64 volatile* ptr) +TEXT ·LoadAcq64(SB),NOSPLIT|NOFRAME,$-8-16 + MOVD ptr+0(FP), R3 + MOVD 0(R3), R3 + CMP R3, R3, CR7 + BC 4, 30, 1(PC) // bne- cr7, 0x4 + ISYNC + MOVD R3, ret+8(FP) + RET |