[nostalgia/core/gba] Add user input support

src/nostalgia/core/gba/addresses.hpp

@@ -62,6 +62,11 @@ using interrupt_handler = void (*)(void);
 #define REG_BG2VOFS *reinterpret_cast<volatile uint32_t*>(0x0400001a)
 #define REG_BG3VOFS *reinterpret_cast<volatile uint32_t*>(0x0400001e)
 
+/////////////////////////////////////////////////////////////////
+// User Input
+
+#define REG_GAMEPAD *reinterpret_cast<volatile uint16_t*>(0x04000130)
+
 /////////////////////////////////////////////////////////////////
 // Memory Addresses
 

src/nostalgia/core/gba/core.cpp

@@ -8,6 +8,7 @@
 
 #include <nostalgia/core/config.hpp>
 #include <nostalgia/core/core.hpp>
+#include <nostalgia/core/input.hpp>
 
 #include "addresses.hpp"
 #include "bios.hpp"
@@ -54,4 +55,8 @@ uint64_t ticksMs() {
 	return g_timerMs;
 }
 
+bool buttonDown(Key k) {
+	return !(REG_GAMEPAD & k);
+}
+
 }