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libsst-os/SST_Time_Win32.c

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+/*
+	SST_Time_Win32.c
+	Author: Patrick Baggett <ptbaggett@762studios.com>
+	Created: 5/29/2013
+
+	Purpose: 
+
+	libsst-os timing functions for Win32
+
+	License:
+
+	This program is free software. It comes without any warranty, to
+	the extent permitted by applicable law. You can redistribute it
+	and/or modify it under the terms of the Do What The Fuck You Want
+	To Public License, Version 2, as published by Sam Hocevar. See
+	http://sam.zoy.org/wtfpl/COPYING for more details.
+
+*/
+
+#include <SST/SST_Time.h>
+#include <windows.h>
+
+static LARGE_INTEGER freq; /* Frequency, as 64-bit integer */
+static double dfreq; /* Frequency, as a double value */
+
+/*
+	Quick note about frequencies:
+
+	x86 PCs typically have various sources of timers, but these 3 are the most common:
+	* RDTSC -- x86 instruction to read a cycle counter, varies per CPU but can be in the low GHz range.
+	* ACPI -- Advanced Configuration and Power Interface timer, about 3.57 MHz (so, about 280 nanosecond accuracy)
+	* i8254 -- Intel chip on keyboard, about 1.193 MHz (so, about 838 nanosecond accuracy)
+*/
+
+int __libsst_init_time()
+{
+	BOOL ok = QueryPerformanceFrequency(&freq);
+	if(ok)
+		dfreq = (double)freq.QuadPart;
+
+	return (int)ok;
+}
+
+uint64_t SST_OS_GetRawTime()
+{
+	LARGE_INTEGER v;
+	QueryPerformanceCounter(&v);
+
+	return (uint64_t)v.QuadPart;
+}
+
+uint64_t SST_OS_GetRawFrequency()
+{
+	return (uint64_t)freq.QuadPart;
+}
+
+uint64_t SST_OS_GetMicroTime()
+{
+	LARGE_INTEGER v;
+	QueryPerformanceCounter(&v);
+
+	return (uint64_t)((v.QuadPart * 1000LL * 1000LL) / freq.QuadPart);
+}
+
+uint64_t SST_OS_GetMilliTime()	/* Not be confused with Miller Time (TM) :D */
+{
+	LARGE_INTEGER v;
+	QueryPerformanceCounter(&v);
+
+	return (uint64_t)((v.QuadPart * 1000LL) / freq.QuadPart);
+}
+
+double SST_OS_GetFloatingTime()
+{
+	LARGE_INTEGER v;
+	QueryPerformanceCounter(&v);
+
+	return (double)v.QuadPart / dfreq;
+
+}