add common function library

src/app/core/common.cc

@@ -0,0 +1,24 @@
+#include "common.h"
+
+#include <cstdint>
+
+namespace yaze {
+namespace app {
+namespace core {
+
+unsigned int SnesToPc(unsigned int addr) {
+  if (addr >= 0x808000) {
+    addr -= 0x808000;
+  }
+  unsigned int temp = (addr & 0x7FFF) + ((addr / 2) & 0xFF8000);
+  return (temp + 0x0);
+}
+
+int AddressFromBytes(uint8_t addr1, uint8_t addr2, uint8_t addr3) {
+  return (addr1 << 16) | (addr2 << 8) | addr3;
+}
+
+
+}  // namespace core
+}  // namespace app
+}  // namespace premia