add a tsc frequency get for windows

1 files changed, 28 insertions, 0 deletions

diff --git a/core/time/tsc_windows.odin b/core/time/tsc_windows.odin
new file mode 100644
index 000000000..635aac2c1
--- /dev/null
+++ b/core/time/tsc_windows.odin
@@ -0,0 +1,28 @@
+//+private
+//+build windows
+package time
+
+import win32 "core:sys/windows"
+
+_get_tsc_frequency :: proc "contextless" () -> u64 {
+	@(static) frequency : u64 = 0
+	if frequency > 0 {
+		return frequency
+	}
+
+	qpc_begin: win32.LARGE_INTEGER
+	win32.QueryPerformanceCounter(&qpc_begin)
+	tsc_begin := intrinsics.read_cycle_counter()
+
+	win32.Sleep(2)
+
+	qpc_end: win32.LARGE_INTEGER
+	win32.QueryPerformanceCounter(&qpc_end)
+	tsc_end := intrinsics.read_cycle_counter()
+
+	qpc_frequency: win32.LARGE_INTEGER
+	win32.QueryPerformanceFrequency(&qpc_frequency)
+
+	frequency = ((tsc_end - tsc_begin) * qpc_frequency) / (qpc_end - qpc_begin)
+	return frequency
+}