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| author | Katie Hockman <katie@golang.org> | 2020-12-14 10:03:05 -0500 |
|---|---|---|
| committer | Katie Hockman <katie@golang.org> | 2020-12-14 10:06:13 -0500 |
| commit | 0345ede87ee12698988973884cfc0fd3d499dffd (patch) | |
| tree | 7123cff141ee5661208d2f5f437b8f5252ac7f6a /src/runtime/internal/atomic/atomic_ppc64x.s | |
| parent | 4651d6b267818b0e0d128a5443289717c4bb8cbc (diff) | |
| parent | 0a02371b0576964e81c3b40d328db9a3ef3b031b (diff) | |
| download | go-0345ede87ee12698988973884cfc0fd3d499dffd.tar.xz | |
[dev.fuzz] all: merge master into dev.fuzz
Change-Id: I5d8c8329ccc9d747bd81ade6b1cb7cb8ae2e94b2
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 |