From 981bc8aa1c924eabc55f63f9671324c548c72d59 Mon Sep 17 00:00:00 2001
From: Morph <39850852+Morph1984@users.noreply.github.com>
Date: Wed, 22 Mar 2023 16:40:41 -0400
Subject: [PATCH] x64: Simplify RDTSC on non-MSVC compilers
Co-Authored-By: liamwhite <liamwhite@users.noreply.github.com>
---
src/common/x64/cpu_wait.cpp | 13 +++++--------
src/common/x64/native_clock.cpp | 13 +++++--------
2 files changed, 10 insertions(+), 16 deletions(-)
diff --git a/src/common/x64/cpu_wait.cpp b/src/common/x64/cpu_wait.cpp
index 1fab0bfe8..cfeef6a3d 100644
--- a/src/common/x64/cpu_wait.cpp
+++ b/src/common/x64/cpu_wait.cpp
@@ -33,16 +33,13 @@ __forceinline static void TPAUSE() {
}
#else
static u64 FencedRDTSC() {
- u64 result;
+ u64 eax;
+ u64 edx;
asm volatile("lfence\n\t"
"rdtsc\n\t"
- "shl $32, %%rdx\n\t"
- "or %%rdx, %0\n\t"
- "lfence"
- : "=a"(result)
- :
- : "rdx", "memory", "cc");
- return result;
+ "lfence\n\t"
+ : "=a"(eax), "=d"(edx));
+ return (edx << 32) | eax;
}
static void TPAUSE() {
diff --git a/src/common/x64/native_clock.cpp b/src/common/x64/native_clock.cpp
index 76c66e7ee..277b00662 100644
--- a/src/common/x64/native_clock.cpp
+++ b/src/common/x64/native_clock.cpp
@@ -27,16 +27,13 @@ __forceinline static u64 FencedRDTSC() {
}
#else
static u64 FencedRDTSC() {
- u64 result;
+ u64 eax;
+ u64 edx;
asm volatile("lfence\n\t"
"rdtsc\n\t"
- "shl $32, %%rdx\n\t"
- "or %%rdx, %0\n\t"
- "lfence"
- : "=a"(result)
- :
- : "rdx", "memory", "cc");
- return result;
+ "lfence\n\t"
+ : "=a"(eax), "=d"(edx));
+ return (edx << 32) | eax;
}
#endif