Implement 8-bit VRAM writes

include/memory.hpp

@@ -95,6 +95,7 @@ namespace KernelMemoryTypes {
 class Memory {
 	u8* fcram;
 	u8* dspRam;
+	u8* vram;  // Provided to the memory class by the GPU class
 
 	u64& cpuTicks; // Reference to the CPU tick counter
 	using SharedMemoryBlock = KernelMemoryTypes::SharedMemoryBlock;
@@ -237,6 +238,7 @@ public:
 	u8* getDSPMem() { return dspRam; }
 	u8* getDSPDataMem() { return &dspRam[DSP_DATA_MEMORY_OFFSET]; }
 	u8* getDSPCodeMem() { return &dspRam[DSP_CODE_MEMORY_OFFSET]; }
-
 	u32 getUsedUserMem() { return usedUserMemory; }
+
+	void setVRAM(u8* pointer) { vram = pointer; }
 };

src/core/PICA/gpu.cpp

@@ -7,6 +7,7 @@ using namespace Floats;
 
 GPU::GPU(Memory& mem) : mem(mem), renderer(*this, regs) {
 	vram = new u8[vramSize];
+	mem.setVRAM(vram); // Give the bus a pointer to our VRAM
 }
 
 void GPU::reset() {
@@ -256,7 +257,6 @@ void GPU::fireDMA(u32 dest, u32 source, u32 size) {
 		std::memcpy(&vram[dest - vramStart], &fcram[source - fcramStart], size);
 	} else {
 		printf("Non-trivially optimizable GPU DMA. Falling back to byte-by-byte transfer");
-		std::memcpy(&vram[dest - vramStart], mem.getReadPointer(source), size);
 
 		for (u32 i = 0; i < size; i++) {
 			mem.write8(dest + i, mem.read8(source + i));

src/core/memory.cpp

@@ -142,10 +142,18 @@ void Memory::write8(u32 vaddr, u8 value) {
 	if (pointer != 0) [[likely]] {
 		*(u8*)(pointer + offset) = value;
 	}
+	else {
+		// VRAM write
+		if (vaddr >= VirtualAddrs::VramStart && vaddr < VirtualAddrs::VramStart + VirtualAddrs::VramSize) {
+			// TODO: Invalidate renderer caches here
+			vram[vaddr - VirtualAddrs::VramStart] = value;
+		} 
+
 		else {
 			Helpers::panic("Unimplemented 8-bit write, addr: %08X, val: %02X", vaddr, value);
 		}
 	}
+}
 
 void Memory::write16(u32 vaddr, u16 value) {
 	const u32 page = vaddr >> pageShift;