From 88e36ebd13b7fe6b02ce04789dc9dedadbb45fa6 Mon Sep 17 00:00:00 2001
From: Ben Kurtovic <ben.kurtovic@gmail.com>
Date: Wed, 25 Mar 2015 01:03:33 -0400
Subject: [PATCH] Add IOManager, which manages emulation rather than the GG
 itself.

---
 crater.c        |  3 ++-
 src/gamegear.c  | 20 +++++++++++++++-----
 src/gamegear.h  |  5 ++++-
 src/iomanager.c | 21 +++++++++++++++++++++
 src/iomanager.h | 10 ++++++++++
 5 files changed, 52 insertions(+), 7 deletions(-)
 create mode 100644 src/iomanager.c
 create mode 100644 src/iomanager.h

diff --git a/crater.c b/crater.c
index 95e3334..2783c86 100644
--- a/crater.c
+++ b/crater.c
@@ -8,6 +8,7 @@
 #include "src/config.h"
 #include "src/disassembler.h"
 #include "src/gamegear.h"
+#include "src/iomanager.h"
 #include "src/logging.h"
 #include "src/rom.h"
 
@@ -48,7 +49,7 @@ int main(int argc, char *argv[])
 
             printf("crater: emulating: %s\n", rom->name);
             gamegear_load(gg, rom);
-            gamegear_power(gg);
+            iomanager_emulate(gg);
 
             gamegear_destroy(gg);
             rom_close(rom);
diff --git a/src/gamegear.c b/src/gamegear.c
index e484967..a587015 100644
--- a/src/gamegear.c
+++ b/src/gamegear.c
@@ -1,6 +1,8 @@
 /* Copyright (C) 2014-2015 Ben Kurtovic <ben.kurtovic@gmail.com>
    Released under the terms of the MIT License. See LICENSE for details. */
 
+#include <stdlib.h>
+
 #include "gamegear.h"
 #include "logging.h"
 
@@ -24,7 +26,7 @@ GameGear* gamegear_create()
 
     Does *not* destroy any loaded ROM objects.
 */
-void gamegear_destroy(GameGear* gg)
+void gamegear_destroy(GameGear *gg)
 {
     free(gg);
 }
@@ -34,17 +36,25 @@ void gamegear_destroy(GameGear* gg)
 
     Does *not* steal the reference to the ROM object.
 */
-void gamegear_load(GameGear* gg, ROM* rom)
+void gamegear_load(GameGear *gg, ROM *rom)
 {
     gg->rom = rom;
 }
 
 /*
-    Powers a GameGear object, beginning emulation.
+    Set the GameGear object's power state (true = on; false = off).
+
+    Powering on the GameGear executes boot code (e.g. clearing memory and
+    setting initial register values) and starts the clock. Powering it off
+    stops the clock.
 
-    This function call blocks until the GameGear is powered off.
+    Setting the power state to its current value has no effect.
 */
-void gamegear_power(GameGear* gg)
+void gamegear_power(GameGear *gg, bool state)
 {
+    if (gg->state == state)
+        return;
+
     // TODO
+    gg->state = state;
 }
diff --git a/src/gamegear.h b/src/gamegear.h
index 056e274..3e5be71 100644
--- a/src/gamegear.h
+++ b/src/gamegear.h
@@ -3,12 +3,15 @@
 
 #pragma once
 
+#include <stdbool.h>
+
 #include "rom.h"
 
 /* Structs */
 
 typedef struct {
     ROM *rom;
+    bool state;
 } GameGear;
 
 /* Functions */
@@ -16,4 +19,4 @@ typedef struct {
 GameGear* gamegear_create();
 void gamegear_destroy(GameGear*);
 void gamegear_load(GameGear*, ROM*);
-void gamegear_power(GameGear*);
+void gamegear_power(GameGear*, bool);
diff --git a/src/iomanager.c b/src/iomanager.c
new file mode 100644
index 0000000..88e68a7
--- /dev/null
+++ b/src/iomanager.c
@@ -0,0 +1,21 @@
+/* Copyright (C) 2014-2015 Ben Kurtovic <ben.kurtovic@gmail.com>
+   Released under the terms of the MIT License. See LICENSE for details. */
+
+#include "iomanager.h"
+#include "logging.h"
+
+/*
+    Emulate a Game Gear. Handle I/O with the host computer.
+
+    Block until emulation is finished.
+*/
+void iomanager_emulate(GameGear *gg)
+{
+    DEBUG("IOManager powering GameGear")
+    gamegear_power(gg, true);
+
+    // TODO
+
+    DEBUG("IOManager unpowering GameGear")
+    gamegear_power(gg, false);
+}
diff --git a/src/iomanager.h b/src/iomanager.h
new file mode 100644
index 0000000..cd71556
--- /dev/null
+++ b/src/iomanager.h
@@ -0,0 +1,10 @@
+/* Copyright (C) 2014-2015 Ben Kurtovic <ben.kurtovic@gmail.com>
+   Released under the terms of the MIT License. See LICENSE for details. */
+
+#pragma once
+
+#include "gamegear.h"
+
+/* Functions */
+
+void iomanager_emulate(GameGear*);