Lay down flash support (doesn't work properly yet)

src/backend/core/mem/Flash.cpp

@@ -0,0 +1,84 @@
+#include <Mem.hpp>
+
+namespace n64 {
+void Flash::Load(SaveType saveType, fs::path path) {
+  if(saveType == SAVE_FLASH_1m) {
+    if(saveData) {
+      memset(saveData, 0xff, 1_mb);
+    } else {
+      saveData = (u8 *) calloc(1_mb, 1);
+    }
+    saveDataPath = path.replace_extension(".flash").string();
+    FILE *f = fopen(saveDataPath.c_str(), "rb");
+    if (!f) {
+      f = fopen(saveDataPath.c_str(), "wb");
+      fwrite(saveData, 1, 1_mb, f);
+      fclose(f);
+      f = fopen(saveDataPath.c_str(), "rb");
+    }
+
+    fseek(f, 0, SEEK_END);
+    size_t actualSize = ftell(f);
+    fseek(f, 0, SEEK_SET);
+    if (actualSize != 1_mb) {
+      Util::panic("Corrupt flash!");
+    }
+
+    fread(saveData, 1, 1_mb, f);
+    fclose(f);
+  }
+}
+
+void Flash::CommandExecute() {
+  Util::debug("Flash::CommandExecute");
+  switch (state) {
+    case FlashState::Idle:
+      break;
+    case FlashState::Erase:
+      for (int i = 0; i < 128; i++) {
+        saveData[eraseOffs + i] = 0xFF;
+      }
+      saveDataDirty = true;
+      break;
+    case FlashState::Write:
+      for (int i = 0; i < 128; i++) {
+        saveData[writeOffs + i] = writeBuf[i];
+      }
+      saveDataDirty = true;
+      break;
+    case FlashState::Read:
+      Util::panic("Execute command when flash in read state");
+      break;
+    case FlashState::Status:
+      break;
+  }
+}
+
+void Flash::CommandStatus() {
+  state = FlashState::Status;
+  status = 0x1111800100C20000;
+}
+
+void Flash::CommandSetEraseOffs(u32 val) {
+  eraseOffs = (val & 0xffff) << 7;
+}
+
+void Flash::CommandErase() {
+  state = FlashState::Erase;
+  status = 0x11118004F0000000;
+}
+
+void Flash::CommandSetWriteOffs(u32 val) {
+  writeOffs = (val & 0xffff) << 7;
+}
+
+void Flash::CommandWrite() {
+  state = FlashState::Write;
+  status = 0x1111800400C20000LL;
+}
+
+void Flash::CommandRead() {
+  state = FlashState::Read;
+  status = 0x11118004F0000000;
+}
+}