From e1873ad2ec5833aaf963fe57e4972c24c5c2a30a Mon Sep 17 00:00:00 2001
From: Lior Halphon <LIJI32@gmail.com>
Date: Mon, 15 Jul 2019 22:01:41 +0300
Subject: [PATCH] Add JOYP write callback API

---
 Core/gb.c  | 5 +++++
 Core/gb.h  | 5 +++++
 Core/sgb.c | 3 +++
 3 files changed, 13 insertions(+)

diff --git a/Core/gb.c b/Core/gb.c
index 6f846ca..a1d0f19 100644
--- a/Core/gb.c
+++ b/Core/gb.c
@@ -906,3 +906,8 @@ double GB_get_usual_frame_rate(GB_gameboy_t *gb)
 {
     return GB_get_clock_rate(gb) / (double)LCDC_PERIOD;
 }
+
+void GB_set_joyp_write_callback(GB_gameboy_t *gb, GB_joyp_write_callback_t callback)
+{
+    gb->joyp_write_callback = callback;
+}
diff --git a/Core/gb.h b/Core/gb.h
index 6d10283..b82d743 100644
--- a/Core/gb.h
+++ b/Core/gb.h
@@ -242,6 +242,7 @@ typedef void (*GB_rumble_callback_t)(GB_gameboy_t *gb, bool rumble_on);
 typedef void (*GB_serial_transfer_bit_start_callback_t)(GB_gameboy_t *gb, bool bit_to_send);
 typedef bool (*GB_serial_transfer_bit_end_callback_t)(GB_gameboy_t *gb);
 typedef void (*GB_update_input_hint_callback_t)(GB_gameboy_t *gb);
+typedef void (*GB_joyp_write_callback_t)(GB_gameboy_t *gb, uint8_t value);
 
 typedef struct {
     bool state;
@@ -533,6 +534,7 @@ struct GB_gameboy_internal_s {
         GB_serial_transfer_bit_start_callback_t serial_transfer_bit_start_callback;
         GB_serial_transfer_bit_end_callback_t serial_transfer_bit_end_callback;
         GB_update_input_hint_callback_t update_input_hint_callback;
+        GB_joyp_write_callback_t joyp_write_callback;
                
         /* IR */
         long cycles_since_ir_change; // In 8MHz units
@@ -691,6 +693,9 @@ bool GB_serial_get_data_bit(GB_gameboy_t *gb);
 void GB_serial_set_data_bit(GB_gameboy_t *gb, bool data);
     
 void GB_disconnect_serial(GB_gameboy_t *gb);
+    
+/* For integration with SFC/SNES emulators */
+void GB_set_joyp_write_callback(GB_gameboy_t *gb, GB_joyp_write_callback_t callback);
 
 #ifdef GB_INTERNAL
 uint32_t GB_get_clock_rate(GB_gameboy_t *gb);
diff --git a/Core/sgb.c b/Core/sgb.c
index a422af0..ccc439a 100644
--- a/Core/sgb.c
+++ b/Core/sgb.c
@@ -295,6 +295,9 @@ static void command_ready(GB_gameboy_t *gb)
 
 void GB_sgb_write(GB_gameboy_t *gb, uint8_t value)
 {
+    if (gb->joyp_write_callback) {
+        gb->joyp_write_callback(gb, value);
+    }
     if (!GB_is_sgb(gb)) return;
     if (!GB_is_hle_sgb(gb)) {
         /* Notify via callback */