From 295fc7d0f8f0b6158307c5c9b11a60516f9eb221 Mon Sep 17 00:00:00 2001
From: Morph <39850852+Morph1984@users.noreply.github.com>
Date: Wed, 28 Jun 2023 01:35:16 -0400
Subject: [PATCH] x64: cpu_wait: Implement MWAITX for non-MSVC compilers
---
src/common/x64/cpu_wait.cpp | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/src/common/x64/cpu_wait.cpp b/src/common/x64/cpu_wait.cpp
index ea16c84900..41d385f598 100644
--- a/src/common/x64/cpu_wait.cpp
+++ b/src/common/x64/cpu_wait.cpp
@@ -47,6 +47,16 @@ static void TPAUSE() {
const auto edx = static_cast<u32>(tsc >> 32);
asm volatile("tpause %0" : : "r"(RequestC02State), "d"(edx), "a"(eax));
}
+
+static void MWAITX() {
+ static constexpr auto EnableWaitTimeFlag = 1U << 1;
+ static constexpr auto RequestC1State = 0U;
+
+ // monitor_var should be aligned to a cache line.
+ alignas(64) u64 monitor_var{};
+ asm volatile("monitorx" : : "a"(&monitor_var), "c"(0), "d"(0));
+ asm volatile("mwaitx" : : "a"(RequestC1State), "b"(PauseCycles), "c"(EnableWaitTimeFlag));
+}
#endif
void MicroSleep() {