From 1e2c621af65cd1bde8ad122be4d4a6d4bb578f25 Mon Sep 17 00:00:00 2001
From: Erik Kundiman <erik@megapahit.org>
Date: Thu, 19 Jun 2025 17:41:15 +0800
Subject: Alternative to rdtsc, for Windows arm64

Just copying from this:
https://forum.juce.com/t/windows-arm64-support/47572/6

This commit is for getting rid of the compile error for now,
we don't know yet if this will work correctly or not.
---
 indra/llcommon/llfasttimer.h | 8 ++++++++
 1 file changed, 8 insertions(+)

(limited to 'indra/llcommon/llfasttimer.h')

diff --git a/indra/llcommon/llfasttimer.h b/indra/llcommon/llfasttimer.h
index a69a03e419..8499655bfa 100644
--- a/indra/llcommon/llfasttimer.h
+++ b/indra/llcommon/llfasttimer.h
@@ -99,7 +99,11 @@ public:
 #if LL_FASTTIMER_USE_RDTSC
     static U32 getCPUClockCount32()
     {
+#if _M_ARM64
+        unsigned __int64 val = _ReadStatusReg(ARM64_PMCCNTR_EL0);
+#else
         unsigned __int64 val = __rdtsc();
+#endif
         val = val >> 8;
         return static_cast<U32>(val);
     }
@@ -107,7 +111,11 @@ public:
     // return full timer value, *not* shifted by 8 bits
     static U64 getCPUClockCount64()
     {
+#if _M_ARM64
+        return static_cast<U64>( _ReadStatusReg(ARM64_PMCCNTR_EL0) );
+#else
         return static_cast<U64>( __rdtsc() );
+#endif
     }
 
 #else
-- 
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