Merge pull request #596 from Kagamiin/feature/vrc-irq-cycle-mode

Implementing cycle IRQ mode for Konami VRC mappers

src/boards/vrc2and4.cpp

@@ -23,7 +23,7 @@
 static bool isPirate;
 static uint8 is22, reg1mask, reg2mask;
 static uint16 IRQCount;
-static uint8 IRQLatch, IRQa;
+static uint8 IRQLatch, IRQa, IRQMode;
 static uint8 prgreg[2], chrreg[8];
 static uint16 chrhi[8];
 static uint8 regcmd, irqcmd, mirr, big_bank;
@@ -45,6 +45,7 @@ static SFORMAT StateRegs[] =
 	{ &IRQCount, 2, "IRQC" },
 	{ &IRQLatch, 1, "IRQL" },
 	{ &IRQa, 1, "IRQA" },
+	{ &IRQMode, 1, "IRQM" },
 	{ 0 }
 };
 
@@ -115,7 +116,7 @@ static DECLFW(VRC24Write) {
 		case 0x9003: regcmd = V; Sync(); break;
 		case 0xF000: X6502_IRQEnd(FCEU_IQEXT); IRQLatch &= 0xF0; IRQLatch |= V & 0xF; break;
 		case 0xF001: X6502_IRQEnd(FCEU_IQEXT); IRQLatch &= 0x0F; IRQLatch |= V << 4; break;
-		case 0xF002: X6502_IRQEnd(FCEU_IQEXT); acount = 0; IRQCount = IRQLatch; IRQa = V & 2; irqcmd = V & 1; break;
+		case 0xF002: X6502_IRQEnd(FCEU_IQEXT); acount = 0; IRQCount = IRQLatch; IRQMode = V & 4; IRQa = V & 2; irqcmd = V & 1; break;
 		case 0xF003: X6502_IRQEnd(FCEU_IQEXT); IRQa = irqcmd; break;
 		}
 }
@@ -136,16 +137,28 @@ static void VRC24Power(void) {
 void VRC24IRQHook(int a) {
 	#define LCYCS 341
 	if (IRQa) {
-		acount += a * 3;
+		if (IRQMode) {
-		if (acount >= LCYCS) {
+			acount += a;
-			while (acount >= LCYCS) {
+			while (acount > 0) {
-				acount -= LCYCS;
+				acount--;
 				IRQCount++;
 				if (IRQCount & 0x100) {
 					X6502_IRQBegin(FCEU_IQEXT);
 					IRQCount = IRQLatch;
 				}
 			}
+		} else {
+			acount += a * 3;
+			if (acount >= LCYCS) {
+				while (acount >= LCYCS) {
+					acount -= LCYCS;
+					IRQCount++;
+					if (IRQCount & 0x100) {
+						X6502_IRQBegin(FCEU_IQEXT);
+						IRQCount = IRQLatch;
+					}
+				}
+			}
 		}
 	}
 }

src/boards/vrc6.cpp

@@ -25,7 +25,7 @@
 
 static uint8 is26;
 static uint8 prg[2], chr[8], mirr;
-static uint8 IRQLatch, IRQa, IRQd;
+static uint8 IRQLatch, IRQa, IRQd, IRQMode;
 static int32 IRQCount, CycleCount;
 static uint8 *WRAM = NULL;
 static uint32 WRAMSIZE;
@@ -40,6 +40,7 @@ static SFORMAT StateRegs[] =
 	{ &IRQLatch, 1, "IRQL" },
 	{ &IRQCount, 4, "IRQC" },
 	{ &CycleCount, 4, "CYCC" },
+	{ &IRQMode, 1, "IRQM" },
 	{ 0 }
 };
 
@@ -109,6 +110,7 @@ static DECLFW(VRC6Write) {
 	case 0xE003: chr[7] = V; Sync(); break;
 	case 0xF000: IRQLatch = V; X6502_IRQEnd(FCEU_IQEXT); break;
 	case 0xF001:
+		IRQMode = V & 4;
 		IRQa = V & 2;
 		IRQd = V & 1;
 		if (V & 2)
@@ -132,13 +134,25 @@ static void VRC6Power(void) {
 
 static void VRC6IRQHook(int a) {
 	if (IRQa) {
-		CycleCount += a * 3;
+		if (IRQMode) {
-		while(CycleCount >= 341) {
+			CycleCount += a;
-			CycleCount -= 341;
+			while (CycleCount > 0) {
-			IRQCount++;
+				CycleCount--;
-			if (IRQCount == 0x100) {
+				IRQCount++;
-				IRQCount = IRQLatch;
+				if (IRQCount & 0x100) {
-				X6502_IRQBegin(FCEU_IQEXT);
+					X6502_IRQBegin(FCEU_IQEXT);
+					IRQCount = IRQLatch;
+				}
+			}
+		} else {
+			CycleCount += a * 3;
+			while(CycleCount >= 341) {
+				CycleCount -= 341;
+				IRQCount++;
+				if (IRQCount == 0x100) {
+					IRQCount = IRQLatch;
+					X6502_IRQBegin(FCEU_IQEXT);
+				}
 			}
 		}
 	}

src/boards/vrc7.cpp

@@ -21,7 +21,7 @@
 #include "mapinc.h"
 
 static uint8 vrc7idx, preg[3], creg[8], mirr;
-static uint8 IRQLatch, IRQa, IRQd;
+static uint8 IRQLatch, IRQa, IRQd, IRQMode;
 static int32 IRQCount, CycleCount;
 static uint8 *WRAM = NULL;
 static uint32 WRAMSIZE;
@@ -44,6 +44,7 @@ static SFORMAT StateRegs[] =
 	{ &IRQCount, 4, "IRQC" },
 	{ &CycleCount, 4, "CYCC" },
 	{ (void**)VRC7Sound_saveptr, sizeof(*VRC7Sound) | FCEUSTATE_INDIRECT, "VRC7"  },
+	{ &IRQMode, 1, "IRQM" },
 	{0}
 };
 
@@ -134,6 +135,7 @@ static DECLFW(VRC7Write) {
 		case 0xE000: mirr = V & 3; Sync(); break;
 		case 0xE010: IRQLatch = V; X6502_IRQEnd(FCEU_IQEXT); break;
 		case 0xF000:
+			IRQMode = V & 4;
 			IRQa = V & 2;
 			IRQd = V & 1;
 			if (V & 2)
@@ -165,13 +167,25 @@ static void VRC7Close(void)
 
 static void VRC7IRQHook(int a) {
 	if (IRQa) {
-		CycleCount += a * 3;
+		if (IRQMode) {
-		while(CycleCount >= 341) {
+			CycleCount += a;
-			CycleCount -= 341;
+			while (CycleCount > 0) {
-			IRQCount++;
+				CycleCount--;
-			if (IRQCount == 0x100) {
+				IRQCount++;
-				IRQCount = IRQLatch;
+				if (IRQCount & 0x100) {
-				X6502_IRQBegin(FCEU_IQEXT);
+					X6502_IRQBegin(FCEU_IQEXT);
+					IRQCount = IRQLatch;
+				}
+			}
+		} else {
+			CycleCount += a * 3;
+			while(CycleCount >= 341) {
+				CycleCount -= 341;
+				IRQCount++;
+				if (IRQCount == 0x100) {
+					IRQCount = IRQLatch;
+					X6502_IRQBegin(FCEU_IQEXT);
+				}
 			}
 		}
 	}