Improvements to IR API, since timing is VERY important

Core/gb.c

@@ -474,6 +474,17 @@ void GB_set_infrared_callback(GB_gameboy_t *gb, GB_infrared_callback_t callback)
 void GB_set_infrared_input(GB_gameboy_t *gb, bool state)
 {
     gb->infrared_input = state;
+    gb->cycles_since_input_ir_change = 0;
+    gb->ir_queue_length = 0;
+}
+
+void GB_queue_infrared_input(GB_gameboy_t *gb, bool state, long cycles_after_previous_change)
+{
+    if (gb->ir_queue_length == GB_MAX_IR_QUEUE) {
+        GB_log(gb, "IR Queue is full\n");
+        return;
+    }
+    gb->ir_queue[gb->ir_queue_length++] = (GB_ir_queue_item_t){state, cycles_after_previous_change};
 }
 
 void GB_set_sample_rate(GB_gameboy_t *gb, unsigned int sample_rate)

Core/gb.h

@@ -28,6 +28,8 @@ enum {
     GB_ZERO_FLAG = 128,
 };
 
+#define GB_MAX_IR_QUEUE 256
+
 enum {
     /* Joypad and Serial */
     GB_IO_JOYP       = 0x00, // Joypad (R/W)
@@ -155,7 +157,7 @@ typedef void (*GB_vblank_callback_t)(GB_gameboy_t *gb);
 typedef void (*GB_log_callback_t)(GB_gameboy_t *gb, const char *string, GB_log_attributes attributes);
 typedef char *(*GB_input_callback_t)(GB_gameboy_t *gb);
 typedef uint32_t (*GB_rgb_encode_callback_t)(GB_gameboy_t *gb, uint8_t r, uint8_t g, uint8_t b);
-typedef void (*GB_infrared_callback_t)(GB_gameboy_t *gb, bool on);
+typedef void (*GB_infrared_callback_t)(GB_gameboy_t *gb, bool on, long cycles_since_last_update);
 
 typedef struct {
     enum {
@@ -172,6 +174,11 @@ typedef struct {
     bool has_rumble;
 } GB_cartridge_t;
 
+typedef struct {
+    bool state;
+    long delay;
+} GB_ir_queue_item_t;
+
 struct GB_breakpoint_s;
 struct GB_watchpoint_s;
 
@@ -349,6 +356,12 @@ typedef struct GB_gameboy_s {
     GB_vblank_callback_t vblank_callback;
     GB_infrared_callback_t infrared_callback;
 
+    /* IR */
+    long cycles_since_ir_change;
+    long cycles_since_input_ir_change;
+    GB_ir_queue_item_t ir_queue[GB_MAX_IR_QUEUE];
+    size_t ir_queue_length;
+
     /*** Debugger ***/
     bool debug_stopped;
     bool debug_fin_command, debug_next_command;
@@ -406,4 +419,5 @@ void GB_set_sample_rate(GB_gameboy_t *gb, unsigned int sample_rate);
 void GB_set_rgb_encode_callback(GB_gameboy_t *gb, GB_rgb_encode_callback_t callback);
 void GB_set_infrared_callback(GB_gameboy_t *gb, GB_infrared_callback_t callback);
 void GB_set_infrared_input(GB_gameboy_t *gb, bool state);
+void GB_queue_infrared_input(GB_gameboy_t *gb, bool state, long cycles_after_previous_change);
 #endif /* GB_h */

Core/memory.c

@@ -166,7 +166,7 @@ static uint8_t read_high_memory(GB_gameboy_t *gb, uint16_t addr)
                 bool read_value = gb->infrared_input || (gb->io_registers[GB_IO_RP] & 1);
                 uint8_t ret = (gb->io_registers[GB_IO_RP] & 0xC1) | 0x3C;
                 if ((gb->io_registers[GB_IO_RP] & 0xC0) == 0xC0 && read_value) {
-                    ret |= read_value;
+                    ret |= 2;
                 }
                 return ret;
             }
@@ -455,7 +455,8 @@ static void write_high_memory(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
                 }
                 if ((value & 1) != (gb->io_registers[GB_IO_RP] & 1)) {
                     if (gb->infrared_callback) {
-                        gb->infrared_callback(gb, value & 1);
+                        gb->infrared_callback(gb, value & 1, gb->cycles_since_ir_change);
+                        gb->cycles_since_ir_change = 0;
                     }
                 }
                 gb->io_registers[GB_IO_RP] = value;

Core/timing.c

@@ -3,6 +3,17 @@
 #include "memory.h"
 #include "display.h"
 
+static void GB_ir_run(GB_gameboy_t *gb)
+{
+    if (gb->ir_queue_length == 0) return;
+    if (gb->cycles_since_input_ir_change >= gb->ir_queue[0].delay) {
+        gb->cycles_since_input_ir_change -= gb->ir_queue[0].delay;
+        gb->infrared_input = gb->ir_queue[0].state;
+        gb->ir_queue_length--;
+        memmove(&gb->ir_queue[0], &gb->ir_queue[1], sizeof(gb->ir_queue[0]) * (gb->ir_queue_length));
+    }
+}
+
 void GB_advance_cycles(GB_gameboy_t *gb, uint8_t cycles)
 {
     // Affected by speed boost
@@ -24,10 +35,13 @@ void GB_advance_cycles(GB_gameboy_t *gb, uint8_t cycles)
     gb->hdma_cycles += cycles;
     gb->display_cycles += cycles;
     gb->apu_cycles += cycles;
+    gb->cycles_since_ir_change += cycles;
+    gb->cycles_since_input_ir_change += cycles;
     GB_hdma_run(gb);
     GB_timers_run(gb);
     GB_apu_run(gb);
     GB_display_run(gb);
+    GB_ir_run(gb);
 }
 
 void GB_timers_run(GB_gameboy_t *gb)