-do frame skipping if running out of audio buffers

-added mappers 94,97 and 180

README.md

@@ -3,7 +3,7 @@ This is yet another NES Emulator which was written so I can learn about the NES,
 If you want to check it out for some reason I do include a windows binary in the "Releases" tab, if you want to compile it go check out the "build" files.  
 You will need freeglut as well as openal-soft to compile the project, it should run on most systems since it is fairly generic C code.  
 NTSC and PAL .nes ROMs are supported right now, it also creates .sav files if the chosen game supports saving.  
-Supported Mappers: 0,1,2,3,4,7,9,10,11,13,15,21,22,23,24,25,26,33,34,36,37,38,44,45,46,47,48,52,66,70,71,78,79,87,99,101,113,133,140,144,145,146,147,148,149,152,185,240 and 242.  
+Supported Mappers: 0,1,2,3,4,7,9,10,11,13,15,21,22,23,24,25,26,33,34,36,37,38,44,45,46,47,48,52,66,70,71,78,79,87,94,97,99,101,113,133,140,144,145,146,147,148,149,152,180,185,240 and 242.  
 To start a game, simply drag and drop its .nes file into it or call it via command line with the .nes file as argument.  
 If you are starting a PAL NES title then make sure it has (E) in the name to be started in PAL mode.  
 You can also play FDS titles if you have the FDS BIOS named disksys.rom in the same folder as your .fds files.  

apu.c

@@ -312,7 +312,7 @@ void apuClockTimers()
 static float lastHPOut = 0, lastLPOut = 0;
 static uint8_t lastP1Out = 0, lastP2Out = 0, lastTriOut = 0, lastNoiseOut = 0;
 
-extern bool emuSkipVsync;
+extern bool emuSkipVsync, emuSkipFrame;
 
 int apuCycle()
 {
@@ -321,13 +321,23 @@ int apuCycle()
 		int updateRes = audioUpdate();
 		if(updateRes == 0)
 		{
+			emuSkipFrame = false;
 			emuSkipVsync = false;
 			return 0;
 		}
-		if(updateRes > 4)
+		if(updateRes > 6)
+		{
 			emuSkipVsync = true;
+			emuSkipFrame = true;
+		}
 		else
-			emuSkipVsync = false;
+		{
+			emuSkipFrame = false;
+			if(updateRes > 2)
+				emuSkipVsync = true;
+			else
+				emuSkipVsync = false;
+		}
 		curBufPos = 0;
 	}
 	uint8_t p1Out = lastP1Out, p2Out = lastP2Out, 

apu.h

@@ -8,7 +8,7 @@
 #ifndef _apu_h_
 #define _apu_h_
 
-#define NUM_BUFFERS 8
+#define NUM_BUFFERS 10
 
 void apuInitBufs();
 void apuDeinitBufs();

main.c

@@ -29,7 +29,7 @@
 #define DEBUG_KEY 0
 #define DEBUG_LOAD_INFO 1
 
-static const char *VERSION_STRING = "fixNES Alpha v0.6.2";
+static const char *VERSION_STRING = "fixNES Alpha v0.6.3";
 
 static void nesEmuDisplayFrame(void);
 static void nesEmuMainLoop(void);
@@ -381,6 +381,7 @@ static void nesEmuDeinit(void)
 
 //used externally
 bool emuSkipVsync = false;
+bool emuSkipFrame = false;
 
 //static int mCycles = 0;
 static bool emuApuDoCycle = false;
@@ -789,6 +790,11 @@ static void nesEmuDisplayFrame()
 {
 	if(emuRenderFrame)
 	{
+		if(emuSkipFrame)
+		{
+			emuRenderFrame = false;
+			return;
+		}
 		if(textureImage != NULL)
 			glTexImage2D(GL_TEXTURE_2D, 0, 4, VISIBLE_DOTS, VISIBLE_LINES, 0, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, textureImage);
 		emuRenderFrame = false;

mapper/p16c8.c

@@ -14,6 +14,7 @@ static uint8_t *p16c8_prgROM;
 static uint8_t *p16c8_chrROM;
 static uint32_t p16c8_prgROMsize;
 static uint32_t p16c8_chrROMsize;
+static uint32_t p16c8_firstPRGBank;
 static uint32_t p16c8_curPRGBank;
 static uint32_t p16c8_curCHRBank;
 static uint32_t p16c8_lastPRGBank;
@@ -28,7 +29,8 @@ void p16c8init(uint8_t *prgROMin, uint32_t prgROMsizeIn,
 	p16c8_prgROMsize = prgROMsizeIn;
 	(void)prgRAMin;
 	(void)prgRAMsizeIn;
-	p16c8_curPRGBank = 0;
+	p16c8_firstPRGBank = 0;
+	p16c8_curPRGBank = p16c8_firstPRGBank;
 	p16c8_lastPRGBank = prgROMsizeIn - 0x4000;
 	if(chrROMsizeIn > 0)
 	{
@@ -54,12 +56,30 @@ uint8_t p16c8get8(uint16_t addr)
 	return p16c8_prgROM[((p16c8_lastPRGBank&~0x3FFF)+(addr&0x3FFF))&(p16c8_prgROMsize-1)];
 }
 
+uint8_t m97_get8(uint16_t addr)
+{
+	if(addr < 0x8000)
+		return 0;
+	if(addr < 0xC000)
+		return p16c8_prgROM[((p16c8_lastPRGBank&~0x3FFF)+(addr&0x3FFF))&(p16c8_prgROMsize-1)];
+	return p16c8_prgROM[((p16c8_curPRGBank&~0x3FFF)+(addr&0x3FFF))&(p16c8_prgROMsize-1)];
+}
+
+uint8_t m180_get8(uint16_t addr)
+{
+	if(addr < 0x8000)
+		return 0;
+	if(addr < 0xC000)
+		return p16c8_prgROM[((p16c8_firstPRGBank&~0x3FFF)+(addr&0x3FFF))&(p16c8_prgROMsize-1)];
+	return p16c8_prgROM[((p16c8_curPRGBank&~0x3FFF)+(addr&0x3FFF))&(p16c8_prgROMsize-1)];
+}
+
 void m2_set8(uint16_t addr, uint8_t val)
 {
 	//printf("p16c8set8 %04x %02x\n", addr, val);
 	if(addr < 0x8000)
 		return;
-	p16c8_curPRGBank = ((val & 15)<<14)&(p16c8_prgROMsize-1);
+	p16c8_curPRGBank = ((val & 0xF)<<14)&(p16c8_prgROMsize-1);
 }
 
 void m70_set8(uint16_t addr, uint8_t val)
@@ -76,20 +96,7 @@ void m71_set8(uint16_t addr, uint8_t val)
 	//printf("p16c8set8 %04x %02x\n", addr, val);
 	if(addr < 0xC000)
 		return;
-	p16c8_curPRGBank = ((val & 15)<<14)&(p16c8_prgROMsize-1);
-}
-
-void m152_set8(uint16_t addr, uint8_t val)
-{
-	//printf("p16c8set8 %04x %02x\n", addr, val);
-	if(addr < 0x8000)
-		return;
-	p16c8_curPRGBank = (((val >> 4)&7)<<14)&(p16c8_prgROMsize-1);
-	p16c8_curCHRBank = ((val & 0xF)<<13)&(p16c8_chrROMsize-1);
-	if((val&0x80) == 0)
-		ppuSetNameTblSingleLower();
-	else
-		ppuSetNameTblSingleUpper();
+	p16c8_curPRGBank = ((val & 0xF)<<14)&(p16c8_prgROMsize-1);
 }
 
 void m78a_set8(uint16_t addr, uint8_t val)
@@ -118,6 +125,58 @@ void m78b_set8(uint16_t addr, uint8_t val)
 		ppuSetNameTblSingleUpper();
 }
 
+void m94_set8(uint16_t addr, uint8_t val)
+{
+	//printf("p16c8set8 %04x %02x\n", addr, val);
+	if(addr < 0x8000)
+		return;
+	p16c8_curPRGBank = (((val>>2) & 0xF)<<14)&(p16c8_prgROMsize-1);
+}
+
+void m97_set8(uint16_t addr, uint8_t val)
+{
+	//printf("p16c8set8 %04x %02x\n", addr, val);
+	if(addr < 0x8000)
+		return;
+	p16c8_curPRGBank = ((val & 0xF)<<14)&(p16c8_prgROMsize-1);
+	switch(val>>6)
+	{
+		case 0:
+			ppuSetNameTblSingleLower();
+			break;
+		case 1:
+			ppuSetNameTblHorizontal();
+			break;
+		case 2:
+			ppuSetNameTblVertical();
+			break;
+		default: //case 3
+			ppuSetNameTblSingleUpper();
+			break;
+	}
+}
+
+void m152_set8(uint16_t addr, uint8_t val)
+{
+	//printf("p16c8set8 %04x %02x\n", addr, val);
+	if(addr < 0x8000)
+		return;
+	p16c8_curPRGBank = (((val >> 4)&7)<<14)&(p16c8_prgROMsize-1);
+	p16c8_curCHRBank = ((val & 0xF)<<13)&(p16c8_chrROMsize-1);
+	if((val&0x80) == 0)
+		ppuSetNameTblSingleLower();
+	else
+		ppuSetNameTblSingleUpper();
+}
+
+void m180_set8(uint16_t addr, uint8_t val)
+{
+	//printf("p16c8set8 %04x %02x\n", addr, val);
+	if(addr < 0x8000)
+		return;
+	p16c8_curPRGBank = ((val & 0xF)<<14)&(p16c8_prgROMsize-1);
+}
+
 uint8_t p16c8chrGet8(uint16_t addr)
 {
 	if(p16c8_chrROM == p16c8_chrRAM) //Writable

mapperList.c

@@ -121,10 +121,10 @@ mapperList_t mapperList[256] = {
 	{ NULL,			NULL,			NULL,			NULL,			NULL,			NULL },
 	{ NULL,			NULL,			NULL,			NULL,			NULL,			NULL },
 	{ NULL,			NULL,			NULL,			NULL,			NULL,			NULL },
+	{ p16c8init,	p16c8get8,		m94_set8,		p16c8chrGet8,	p16c8chrSet8,	NULL },
 	{ NULL,			NULL,			NULL,			NULL,			NULL,			NULL },
 	{ NULL,			NULL,			NULL,			NULL,			NULL,			NULL },
-	{ NULL,			NULL,			NULL,			NULL,			NULL,			NULL },
-	{ NULL,			NULL,			NULL,			NULL,			NULL,			NULL },
+	{ p16c8init,	m97_get8,		m97_set8,		p16c8chrGet8,	p16c8chrSet8,	NULL },
 	{ NULL,			NULL,			NULL,			NULL,			NULL,			NULL },
 	{ p8c8init,		p8c8get8,		m99_set8,		p8c8chrGet8,	p8c8chrSet8,	NULL },
 	{ NULL,			NULL,			NULL,			NULL,			NULL,			NULL },
@@ -207,7 +207,7 @@ mapperList_t mapperList[256] = {
 	{ NULL,			NULL,			NULL,			NULL,			NULL,			NULL },
 	{ NULL,			NULL,			NULL,			NULL,			NULL,			NULL },
 	{ NULL,			NULL,			NULL,			NULL,			NULL,			NULL },
-	{ NULL,			NULL,			NULL,			NULL,			NULL,			NULL },
+	{ p16c8init,	m180_get8,		m180_set8,		p16c8chrGet8,	p16c8chrSet8,	NULL },
 	{ NULL,			NULL,			NULL,			NULL,			NULL,			NULL },
 	{ NULL,			NULL,			NULL,			NULL,			NULL,			NULL },
 	{ NULL,			NULL,			NULL,			NULL,			NULL,			NULL },

mapper_h/p16c8.h

@@ -12,12 +12,17 @@ void p16c8init(uint8_t *prgROM, uint32_t prgROMsize,
 			uint8_t *prgRAM, uint32_t prgRAMsize,
 			uint8_t *chrROM, uint32_t chrROMsize);
 uint8_t p16c8get8(uint16_t addr);
+uint8_t m97_get8(uint16_t addr);
+uint8_t m180_get8(uint16_t addr);
 void m2_set8(uint16_t addr, uint8_t val);
 void m70_set8(uint16_t addr, uint8_t val);
 void m71_set8(uint16_t addr, uint8_t val);
 void m78a_set8(uint16_t addr, uint8_t val);
 void m78b_set8(uint16_t addr, uint8_t val);
+void m94_set8(uint16_t addr, uint8_t val);
+void m97_set8(uint16_t addr, uint8_t val);
 void m152_set8(uint16_t addr, uint8_t val);
+void m180_set8(uint16_t addr, uint8_t val);
 uint8_t p16c8chrGet8(uint16_t addr);
 void p16c8chrSet8(uint16_t addr, uint8_t val);