bootrom mostly works, refactoring and all opcodes added

src/timing.cpp

@@ -0,0 +1,12 @@
+#include "gameboy.hpp"
+
+//handles most of the behavoir as described here: https://gbdev.io/pandocs/Timer_and_Divider_Registers.html#ff04--div-divider-register
+void GameBoy::timingHandler() {
+	if (cycles - lastDivUpdate >= DIVIDER_REGISTER_FREQ) {
+		const uint8_t increments = (cycles - lastDivUpdate) / DIVIDER_REGISTER_FREQ;
+
+		(*DIV) += increments;
+
+		lastDivUpdate += increments * DIVIDER_REGISTER_FREQ;
+	}
+}