Finish ppu, and mbc1 mapping

lib/gamepad.c

@@ -0,0 +1,65 @@
+#include <gamepad.h>
+#include <string.h>
+
+typedef struct {
+    bool button_sel;
+    bool dir_sel;
+    gamepad_state controller;
+} gamepad_context;
+
+static gamepad_context ctx = {0};
+
+void gamepad_init();
+
+bool gamepad_button_sel(){
+    return ctx.button_sel;
+}
+
+bool gamepad_dir_sel(){
+    return ctx.dir_sel;
+}
+
+void gamepad_set_sel(u8 value){
+    ctx.button_sel = value & 0x20;
+    ctx.dir_sel = value & 0x10;
+}
+
+gamepad_state *gamepad_get_state(){
+    return &ctx.controller;
+}
+
+u8 gamepad_get_output() {
+    u8 output = 0xCF;
+
+    if(!gamepad_button_sel()) {
+        if (gamepad_get_state()->start) {
+            output &= ~(1 << 3);
+        }
+        if (gamepad_get_state()->select) {
+            output &= ~(1 << 2);
+        }
+        if (gamepad_get_state()->a) {
+            output &= ~(1 << 0);
+        }
+        if (gamepad_get_state()->b) {
+            output &= ~(1 << 1);
+        }
+    }
+
+    if(!gamepad_dir_sel()) {
+        if (gamepad_get_state()->left) {
+            output &= ~(1 << 1);
+        }
+        if (gamepad_get_state()->right) {
+            output &= ~(1 << 0);
+        }
+        if (gamepad_get_state()->up) {
+            output &= ~(1 << 2);
+        }
+        if (gamepad_get_state()->down) {
+            output &= ~(1 << 3);
+        }
+    }
+
+    return output;
+}