diff --git a/Core/joypad.c b/Core/joypad.c
index c0655f0..b916447 100644
--- a/Core/joypad.c
+++ b/Core/joypad.c
@@ -91,3 +91,31 @@ void GB_set_key_state_for_player(GB_gameboy_t *gb, GB_key_t index, unsigned play
     gb->keys[player][index] = pressed;
     GB_update_joyp(gb);
 }
+
+void GB_set_key_mask(GB_gameboy_t *gb, GB_key_mask_t mask)
+{
+    memset(gb->keys, 0, sizeof(gb->keys));
+    bool *key = &gb->keys[0][0];
+    while (mask) {
+        if (mask & 1) {
+            *key = true;
+        }
+        mask >>= 1;
+    }
+    
+    GB_update_joyp(gb);
+}
+
+void GB_set_key_mask_for_player(GB_gameboy_t *gb, GB_key_mask_t mask, unsigned player)
+{
+    memset(gb->keys[player], 0, sizeof(gb->keys[player]));
+    bool *key = gb->keys[player];
+    while (mask) {
+        if (mask & 1) {
+            *key = true;
+        }
+        mask >>= 1;
+    }
+    
+    GB_update_joyp(gb);
+}
diff --git a/Core/joypad.h b/Core/joypad.h
index 615e34a..beb532e 100644
--- a/Core/joypad.h
+++ b/Core/joypad.h
@@ -15,8 +15,24 @@ typedef enum {
     GB_KEY_MAX
 } GB_key_t;
 
+typedef enum {
+    GB_KEY_RIGHT_MASK = 1 << GB_KEY_RIGHT,
+    GB_KEY_LEFT_MASK = 1 << GB_KEY_LEFT,
+    GB_KEY_UP_MASK = 1 << GB_KEY_UP,
+    GB_KEY_DOWN_MASK = 1 << GB_KEY_DOWN,
+    GB_KEY_A_MASK = 1 << GB_KEY_A,
+    GB_KEY_B_MASK = 1 << GB_KEY_B,
+    GB_KEY_SELECT_MASK = 1 << GB_KEY_SELECT,
+    GB_KEY_START_MASK = 1 << GB_KEY_START,
+} GB_key_mask_t;
+
+// For example, for player 2's (0-based; logical player 3) A button, use GB_MASK_FOR_PLAYER(GB_KEY_A_MASK, 2)
+#define GB_MASK_FOR_PLAYER(mask, player) ((x) << (player * 8))
+
 void GB_set_key_state(GB_gameboy_t *gb, GB_key_t index, bool pressed);
 void GB_set_key_state_for_player(GB_gameboy_t *gb, GB_key_t index, unsigned player, bool pressed);
+void GB_set_key_mask(GB_gameboy_t *gb, GB_key_mask_t mask);
+void GB_set_key_mask_for_player(GB_gameboy_t *gb, GB_key_mask_t mask, unsigned player);
 void GB_icd_set_joyp(GB_gameboy_t *gb, uint8_t value);
 
 #ifdef GB_INTERNAL