[PICA] Fix more shader bugs

src/core/PICA/regs.cpp

@@ -113,6 +113,10 @@ void GPU::writeInternalReg(u32 index, u32 value, u32 mask) {
 			shaderUnit.vs.uploadWord(value);
 			break;
 
+		case VertexShaderEntrypoint:
+			shaderUnit.vs.entrypoint = value & 0xffff;
+			break;
+
 		case VertexShaderTransferEnd:
 			if (value != 0) shaderUnit.vs.finalize();
 			break;

src/core/PICA/shader_interpreter.cpp

@@ -2,7 +2,7 @@
 #include <cmath>
 
 void PICAShader::run() {
-	pc = 0;
+	pc = entrypoint;
 	loopIndex = 0;
 	ifIndex = 0;
 	callIndex = 0;
@@ -63,7 +63,7 @@ void PICAShader::run() {
 		// Handle calls
 		if (callIndex != 0) {
 			auto& info = callInfo[callIndex - 1];
-			if (pc == info.endingPC) { // Check if the IF block ended
+			if (pc == info.endingPC) { // Check if the CALL block ended
 				pc = info.returnPC;
 				callIndex -= 1;
 			}
@@ -121,7 +121,7 @@ bool PICAShader::isCondTrue(u32 instruction) {
 			return cmpRegister[0] == refX && cmpRegister[1] == refY;
 		case 2: // At least cmp.x matches
 			return cmpRegister[0] == refX;
-		case 3: // At least cmp.y matches
+		default: // At least cmp.y matches
 			return cmpRegister[1] == refY;
 	}
 }