i_system.cpp.patch

--- src/sdl/i_system.cpp.orig	2016-02-10 03:55:38.747944750 -0600
+++ src/sdl/i_system.cpp	2016-02-10 03:58:18.228957592 -0600
@@ -137,14 +137,13 @@
 
 
 static DWORD TicStart;
-static DWORD TicNext;
 static DWORD BaseTime;
 static int TicFrozen;
 
 // Signal based timer.
 static Semaphore timerWait;
 static int tics;
-static DWORD sig_start, sig_next;
+static DWORD sig_start;
 
 void I_SelectTimer();
 
@@ -183,7 +182,6 @@
 	if (saveMS)
 	{
 		TicStart = tm;
-		TicNext = Scale((Scale (tm, TICRATE, 1000) + 1), 1000, TICRATE);
 	}
 	return Scale(tm - BaseTime, TICRATE, 1000);
 }
@@ -193,7 +191,6 @@
 	if (saveMS)
 	{
 		TicStart = sig_start;
-		TicNext = sig_next;
 	}
 	return tics;
 }
@@ -264,7 +261,6 @@
 	if(!TicFrozen)
 		tics++;
 	sig_start = SDL_GetTicks();
-	sig_next = Scale((Scale (sig_start, TICRATE, 1000) + 1), 1000, TICRATE);
 	SEMAPHORE_SIGNAL(timerWait)
 }
 
@@ -308,15 +304,14 @@
 fixed_t I_GetTimeFrac (uint32 *ms)
 {
 	DWORD now = SDL_GetTicks ();
-	if (ms) *ms = TicNext;
-	DWORD step = TicNext - TicStart;
-	if (step == 0)
+	if (ms) *ms = TicStart + (1000 / TICRATE);
+	if (TicStart == 0)
 	{
 		return FRACUNIT;
 	}
 	else
 	{
-		fixed_t frac = clamp<fixed_t> ((now - TicStart)*FRACUNIT/step, 0, FRACUNIT);
+		fixed_t frac = clamp<fixed_t> ((now - TicStart)*FRACUNIT*TICRATE/1000, 0, FRACUNIT);
 		return frac;
 	}
 }