scawful/yaze
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Get ROM header and execute at Reset Vector

Browse Source
This commit is contained in:
scawful
2023-08-20 20:10:41 -04:00
parent 7e28cec0ec
commit 8fb55b64bc
1 changed files with 15 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files

23
src/app/emu/snes.cc
View File

@@ -15,22 +15,26 @@ namespace app {
namespace emu { namespace emu {
namespace { namespace {
uint8_t GetHeaderOffset(const Memory& memory) {
uint16_t GetHeaderOffset(const Memory& memory) {
uint8_t mapMode = memory[(0x00 << 16) + 0xFFD5]; uint8_t mapMode = memory[(0x00 << 16) + 0xFFD5];
uint8_t offset; uint16_t offset;
switch (mapMode & 0x07) { switch (mapMode & 0x07) {
case 0: // LoROM case 0: // LoROM
offset = 0x7F; // offset = 0x7F;
offset = 0xFFC0;
break; break;
case 1: // HiROM case 1: // HiROM
offset = 0xFF; offset = 0xFFC0;
break; break;
case 5: // ExHiROM case 5: // ExHiROM
offset = 0x40; offset = 0x40;
break; break;
default: default:
throw std::runtime_error("Unsupported map mode"); throw std::invalid_argument(
"Unable to locate supported ROM mapping mode in the provided ROM "
"file. Please try another ROM file.");
} }
return offset; return offset;
@@ -160,8 +164,11 @@ void SNES::Init(ROM& rom) {
rom_info_ = ReadRomHeader(header_offset); rom_info_ = ReadRomHeader(header_offset);
// Perform a long jump into a FastROM bank (if the ROM speed is FastROM) // Perform a long jump into a FastROM bank (if the ROM speed is FastROM)
// Disable the emulation flag (switch to 65816 native mode)s // Disable the emulation flag (switch to 65816 native mode)
// Initialize CPU
cpu.Init(); cpu.Init();
cpu.PC = rom_info_.resetVector;
// Initialize PPU // Initialize PPU
ppu.Init(); ppu.Init();
@@ -275,7 +282,7 @@ void SNES::Run() {
auto lastTime = std::chrono::high_resolution_clock::now(); auto lastTime = std::chrono::high_resolution_clock::now();
while (running_) { if (running_) {
auto currentTime = std::chrono::high_resolution_clock::now(); auto currentTime = std::chrono::high_resolution_clock::now();
double deltaTime = double deltaTime =
std::chrono::duration<double>(currentTime - lastTime).count(); std::chrono::duration<double>(currentTime - lastTime).count();
@@ -287,7 +294,7 @@ void SNES::Run() {
frameAccumulatedTime += deltaTime; frameAccumulatedTime += deltaTime;
while (cpuAccumulatedTime >= cpuCycleTime) { while (cpuAccumulatedTime >= cpuCycleTime) {
cpu.ExecuteInstruction(cpu.ReadByte(cpu.PC)); cpu.ExecuteInstruction(cpu.FetchByte());
cpuAccumulatedTime -= cpuCycleTime; cpuAccumulatedTime -= cpuCycleTime;
} }