X-Git-Url: http://shamusworld.gotdns.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Fsound.cpp;h=8010d8985667c04bae056bcfe51c6f5d42cfa0fb;hb=f9851983d3f21e480f2c03af10fa6ace79473d0c;hp=281aee286f8894a56175a9141a9cf26a8aa54085;hpb=f84e14d43ea0dff77d4b216b50e5de5b1d2efabc;p=stargem2

diff --git a/src/sound.cpp b/src/sound.cpp
index 281aee2..8010d89 100755
--- a/src/sound.cpp
+++ b/src/sound.cpp
@@ -10,6 +10,8 @@
 // ---  ----------  ------------------------------------------------------------
 // JLH  06/15/2006  Added changelog ;-)
 // JLH  06/15/2006  Scrubbed all BYTE, WORD & DWORD references from the code
+// JLH  02/10/2009  Fixed sound IRQ callback so that CPU samples are taken at
+//                  cycle exact boundaries
 //
 // Notes:
 //   The sound CPU (6808) runs at 894,750 (3,579,000 / 4) Hz.
@@ -87,15 +89,15 @@ void SDLSoundCallback(void * userdata, Uint8 * buffer, int length)
 
 #define CYCLE_EXACT_SOUND
 #ifdef CYCLE_EXACT_SOUND
-	float overflow = 0.0;
-	uint32 time = 20;
+	static float overflow = 0.0;
+	static uint32 time = 20;
 #endif
 
 	while (cnt != length)
 	{
 		// This is close, but not cycle exact (exact would be 20.289115646...)
 
-//Need to figure out how to get that fraction to execute... !!! FIX !!!
+//Need to figure out how to get that fraction to execute... !!! FIX !!! [DONE]
 /*
 One way would be to use a fractional accumulator, then subtract 1 every
 time it overflows. Like so:
@@ -124,7 +126,7 @@ while (!done)
 #endif
 		buffer[cnt++] = sram[0x0400];				// Fill the buffer with the PIA output value
 #ifdef CYCLE_EXACT_SOUND
-		overflow += 0.289115646;
+		overflow += 0.289115646;					// Fractional part of CPU cycles...
 
 		if (overflow > 1.0)
 		{