Remove unneeded volatility, enabling more optimisations. Sound volatility is #define'd away, GUI volatility is simply removed.

Makefile

@@ -70,7 +70,7 @@ DEFS   := -DSPC700_C -DEXECUTE_SUPERFX_PER_LINE -DSDD1_DECOMP \
           -DVAR_CYCLES -DCPU_SHUTDOWN -DSPC700_SHUTDOWN \
           -DNO_INLINE_SET_GET -DNOASM -DHAVE_MKSTEMP '-DACCEPT_SIZE_T=size_t' \
           -DUNZIP_SUPPORT -DFOREVER_16_BIT_SOUND -DFOREVER_STEREO \
-          -DFOREVER_FORWARD_STEREO -DSYNC_JOYPAD_AT_HBLANK
+          -DFOREVER_FORWARD_STEREO -DNO_VOLATILE_SOUND -DSYNC_JOYPAD_AT_HBLANK
 
 .PHONY: clean makedirs
 .SUFFIXES: .elf .dat .plg

source/globals.cpp

@@ -216,7 +216,14 @@ uint32 current_graphic_format = RGB565;
 
 struct SCheatData Cheat;
 
+// Define NO_VOLATILE_SOUND if you're always reading or writing sound from one
+// thread or one co-routine. If you're using interrupts or a thread, sound must
+// be volatile.
+#ifndef NO_VOLATILE_SOUND
 volatile SoundStatus so;
+#else
+SoundStatus so;
+#endif
 
 int Echo [24000];
 int DummyEchoBuffer [SOUND_BUFFER_SIZE];

source/nds/draw.c

@@ -142,7 +142,7 @@ void drawhline(void* screen_addr, u32 sx, u32 ex, u32 y, u32 color)
 {
 	u32 x;
 	u32 width  = (ex - sx) + 1;
-	volatile u16 *dst = VRAM_POS(screen_addr, sx, y);
+	u16 *dst = VRAM_POS(screen_addr, sx, y);
 
 	for (x = 0; x < width; x++)
 		*dst++ = (u16)color;
@@ -155,7 +155,7 @@ void drawvline(void* screen_addr, u32 x, u32 sy, u32 ey, u32 color)
 {
 	int y;
 	int height = (ey - sy) + 1;
-	volatile u16 *dst = VRAM_POS(screen_addr, x, sy);
+	u16 *dst = VRAM_POS(screen_addr, x, sy);
 
 	for (y = 0; y < height; y++)
 	{
@@ -183,7 +183,7 @@ void drawboxfill(void* screen_addr, u32 sx, u32 sy, u32 ex, u32 ey, u32 color)
 	u32 x, y;
 	u32 width  = (ex - sx) + 1;
 	u32 height = (ey - sy) + 1;
-	volatile u16 *dst = VRAM_POS(screen_addr, sx, sy);
+	u16 *dst = VRAM_POS(screen_addr, sx, sy);
 
 	for (y = 0; y < height; y++)
 	{

source/nds/entry.cpp

@@ -34,10 +34,6 @@ static u8 Buf[MAX_BUFFER_SIZE];
 #define FIXED_POINT_SHIFT 16
 #define FIXED_POINT_REMAINDER 0xffff
 
-static volatile bool8 block_signal = FALSE;
-static volatile bool8 pending_signal = FALSE;
-static volatile bool8 DelayingForEarlyFrame = FALSE;
-
 void S9xMessage (int /*type*/, int /*number*/, const char *message)
 {
 #if 1
@@ -677,12 +673,10 @@ void S9xSyncSpeed ()
 		else // Early
 		{
 			skip_rate = 0;
-			DelayingForEarlyFrame = TRUE;
 			ds2_setCPUclocklevel(0);
 			if (syncdif > 0)
 				udelay(syncdif * 128 / 3 /* times 42 + 2/3 microseconds */);
 			set_cpu_clock(clock_speed_number);
-			DelayingForEarlyFrame = FALSE;
 			S9xProcessSound (0);
 
 			IPPU.RenderThisFrame = TRUE;
@@ -712,11 +706,9 @@ void S9xSyncSpeed ()
 			syncdif = sync_next - syncnow;
 			if (syncdif > 0)
 			{
-				DelayingForEarlyFrame = TRUE;
 				ds2_setCPUclocklevel(0);
 				udelay(syncdif * 128 / 3 /* times 42 + 2/3 microseconds */);
 				set_cpu_clock(clock_speed_number);
-				DelayingForEarlyFrame = FALSE;
 				S9xProcessSound (0);
 				// After that little delay, what time is it?
 				syncnow = getSysTime();
@@ -846,8 +838,6 @@ bool8 S9xOpenSoundDevice (int mode, bool8 stereo, int buffer_size)
 
 void S9xGenerateSound ()
 {
-	block_signal = TRUE;
-
 #ifndef FOREVER_16_BIT_SOUND
 	int bytes_so_far = so.sixteen_bit ? (so.samples_mixed_so_far << 1) :
 		so.samples_mixed_so_far;
@@ -856,7 +846,7 @@ void S9xGenerateSound ()
 #endif
 
 	if (bytes_so_far >= so.buffer_size)
-		goto end;
+		return;
 
 	so.err_counter += so.err_rate;
 	if (so.err_counter >= FIXED_POINT)
@@ -909,37 +899,17 @@ void S9xGenerateSound ()
 			byte_offset = (byte_offset + bytes_this_run) & SOUND_BUFFER_SIZE_MASK;
 		} while (samples_to_write > 0);
 	}
-
-end:
-
-	if (pending_signal)
-	{
-		block_signal = FALSE;
-		pending_signal = FALSE;
-		S9xProcessSound (0);
-	}
-	else
-		block_signal = FALSE;
 }
 
 void S9xProcessSound (unsigned int)
 {
-	if (DelayingForEarlyFrame)
-		set_cpu_clock(clock_speed_number);
-
-	if (block_signal)
-	{
-		pending_signal = TRUE;
-		goto end;
-	}
-
 	unsigned short *audiobuff;
 
-	if (Settings.Paused || so.mute_sound || !game_enable_audio)
-		goto end;
+	if (so.mute_sound || !game_enable_audio)
+		return;
 
 	if(ds2_checkAudiobuff() > 4)
-		goto end;
+		return;
 
 	/* Number of samples to generate now */
 	int sample_count;
@@ -959,7 +929,7 @@ void S9xProcessSound (unsigned int)
 	audiobuff = (unsigned short*)ds2_getAudiobuff();
 	if(NULL == audiobuff)	//There are audio queue in sending or wait to send
 	{
-		goto end;
+		return;
 	}
 
 	/* If we need more audio samples */
@@ -1075,10 +1045,6 @@ void S9xProcessSound (unsigned int)
 	}
 
 	so.samples_mixed_so_far -= sample_count;
-
-end:
-	if (DelayingForEarlyFrame)
-		ds2_setCPUclocklevel(0);
 }
 
 /*

source/soundux.h

@@ -144,7 +144,14 @@ typedef struct {
     uint32 err_rate;
 } SoundStatus;
 
+// Define NO_VOLATILE_SOUND if you're always reading or writing sound from one
+// thread or one co-routine. If you're using interrupts or a thread, sound must
+// be volatile.
+#ifndef NO_VOLATILE_SOUND
 EXTERN_C volatile SoundStatus so;
+#else
+EXTERN_C SoundStatus so;
+#endif
 
 typedef struct {
     int state;