[GPU] Get PICA register access working

src/core/PICA/gpu.cpp

@@ -2,7 +2,8 @@
 #include <cstdio>
 
 void GPU::reset() {
-
+	regs.fill(0);
+	// TODO: Reset blending, texturing, etc here
 }
 
 void GPU::clearBuffer(u32 startAddress, u32 endAddress, u32 value, u32 control) {

src/core/PICA/regs.cpp

@@ -0,0 +1,40 @@
+#include "gpu.hpp"
+
+u32 GPU::readReg(u32 address) {
+	printf("Ignoring read from GPU register %08X\n", address);
+	return 0;
+}
+
+void GPU::writeReg(u32 address, u32 value) {
+	if (address >= 0x1EF01000 && address < 0x1EF01C00) { // Internal registers
+		const u32 index = (address - 0x1EF01000) / sizeof(u32);
+		writeInternalReg(index, value, 0xffffffff);
+	} else {
+		Helpers::panic("Ignoring write to GPU register %08X. Value: %08X\n", address, value);
+	}
+}
+
+u32 GPU::readInternalReg(u32 index) {
+	if (index > regNum) {
+		printf("Tried to read invalid GPU register. Index: %X\n", index);
+		return 0;
+	}
+
+	return regs[index];
+}
+
+void GPU::writeInternalReg(u32 index, u32 value, u32 mask) {
+	if (index > regNum) {
+		Helpers::panic("Tried to write to invalid GPU register. Index: %X, value: %08X\n", index, value);
+		return;
+	}
+
+	u32 currentValue = regs[index];
+	u32 newValue = (currentValue & ~mask) | (value & mask); // Only overwrite the bits specified by "mask"
+
+	switch (index) {
+		default:
+			printf("GPU: Wrote to unimplemented internal reg: %X, value: %08X\n", index, newValue);
+			break;
+	}
+}