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| author | Jason A. Donenfeld <Jason@zx2c4.com> | 2021-11-03 18:19:04 +0100 |
|---|---|---|
| committer | Jason A. Donenfeld <Jason@zx2c4.com> | 2021-11-03 18:37:22 +0000 |
| commit | cfd016df1fba2a2a104f4cca705aa4357777986b (patch) | |
| tree | a0704332a5565aa06525c733d7e935dab7eb2451 /src/runtime/sys_windows_amd64.s | |
| parent | d4e0e8e4a41e5e1e7d0359287a1015791ce778ed (diff) | |
| download | go-cfd016df1fba2a2a104f4cca705aa4357777986b.tar.xz | |
runtime: on windows, read nanotime with one instruction or issue barrier
On 64-bit, this is more efficient, and on ARM64, this prevents the time
from moving backwards due to the weaker memory model. On ARM32 due to
the weaker memory model, we issue a memory barrier.
Updates #48072.
Change-Id: If4695716c3039d8af14e14808af217f5c99fc93a
Reviewed-on: https://go-review.googlesource.com/c/go/+/361057
Trust: Jason A. Donenfeld <Jason@zx2c4.com>
Run-TryBot: Jason A. Donenfeld <Jason@zx2c4.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Diffstat (limited to 'src/runtime/sys_windows_amd64.s')
| -rw-r--r-- | src/runtime/sys_windows_amd64.s | 13 |
1 files changed, 3 insertions, 10 deletions
diff --git a/src/runtime/sys_windows_amd64.s b/src/runtime/sys_windows_amd64.s index 1e4c1d2b61..1467b4d57b 100644 --- a/src/runtime/sys_windows_amd64.s +++ b/src/runtime/sys_windows_amd64.s @@ -344,16 +344,9 @@ TEXT runtime·nanotime1(SB),NOSPLIT,$0-8 CMPB runtime·useQPCTime(SB), $0 JNE useQPC MOVQ $_INTERRUPT_TIME, DI -loop: - MOVL time_hi1(DI), AX - MOVL time_lo(DI), BX - MOVL time_hi2(DI), CX - CMPL AX, CX - JNE loop - SHLQ $32, CX - ORQ BX, CX - IMULQ $100, CX - MOVQ CX, ret+0(FP) + MOVQ time_lo(DI), AX + IMULQ $100, AX + MOVQ AX, ret+0(FP) RET useQPC: JMP runtime·nanotimeQPC(SB) |