@@ -150,6 +150,12 @@ case REG_TM3CNT_LO:
 		GBATimerUpdateRegister(gba, 3);
 		break;
 
+	case REG_KEYINPUT:
+		if (gba->keySource) {
+			return 0x3FF ^ *gba->keySource;
+		}
+		break;
+
 	case REG_DMA0CNT_LO:
 	case REG_DMA1CNT_LO:
 	case REG_DMA2CNT_LO:

@@ -26,6 +26,7 @@ if (threadContext->fd >= 0) {
 		GBALoadROM(&gba, threadContext->fd);
 	}
 	GBAAttachDebugger(&gba, &debugger);
+	gba.keySource = &threadContext->activeKeys;
 
 	threadContext->started = 1;
 	pthread_mutex_lock(&threadContext->mutex);
@@ -51,6 +52,7 @@ pthread_mutex_init(&threadContext->mutex, 0);
 	pthread_cond_init(&threadContext->cond, 0);
 
 	pthread_mutex_lock(&threadContext->mutex);
+	threadContext->activeKeys = 0;
 	threadContext->started = 0;
 	pthread_create(&threadContext->thread, 0, _GBAThreadRun, threadContext);
 	pthread_cond_wait(&threadContext->cond, &threadContext->mutex);

@@ -12,6 +12,7 @@
 	// Input
 	struct GBAVideoRenderer* renderer;
 	int fd;
+	int activeKeys;
 
 	// Threading state
 	pthread_mutex_t mutex;

@@ -44,6 +44,7 @@
 	memset(gba->timers, 0, sizeof(gba->timers));
 
 	gba->springIRQ = 0;
+	gba->keySource = 0;
 
 	ARMReset(&gba->cpu);
 }

@@ -33,6 +33,19 @@ GBA_LOG_STUB,
 	GBA_LOG_WARN
 };
 
+enum GBAKey {
+	GBA_KEY_A = 0,
+	GBA_KEY_B = 1,
+	GBA_KEY_SELECT = 2,
+	GBA_KEY_START = 3,
+	GBA_KEY_RIGHT = 4,
+	GBA_KEY_LEFT = 5,
+	GBA_KEY_UP = 6,
+	GBA_KEY_DOWN = 7,
+	GBA_KEY_R = 8,
+	GBA_KEY_L = 9
+};
+
 struct GBABoard {
 	struct ARMBoard d;
 	struct GBA* p;
@@ -60,6 +73,7 @@ unsigned enable : 1;
 	} timers[4];
 
 	int springIRQ;
+	int* keySource;
 
 	enum GBAError errno;
 	const char* errstr;

@@ -1,5 +1,6 @@
 #include "debugger.h"
 #include "gba-thread.h"
+#include "gba.h"
 #include "renderers/video-software.h"
 
 #include <sdl.h>
@@ -19,6 +20,7 @@
 static int _GBASDLInit(struct GLSoftwareRenderer* renderer);
 static void _GBASDLDeinit(struct GLSoftwareRenderer* renderer);
 static void _GBASDLRunloop(struct GBAThread* context, struct GLSoftwareRenderer* renderer);
+static void _GBASDLHandleKeypress(struct GBAThread* context, const struct SDL_KeyboardEvent* event);
 
 static const GLint _glVertices[] = {
 	0, 0,
@@ -112,8 +114,17 @@ SDL_GL_SwapBuffers();
 		pthread_mutex_lock(&renderer->d.mutex);
 		pthread_cond_broadcast(&renderer->d.cond);
 		pthread_mutex_unlock(&renderer->d.mutex);
-		while(SDL_PollEvent(&event)) {
-			
+		while (SDL_PollEvent(&event)) {
+			switch (event.type) {
+			case SDL_QUIT:
+				// FIXME: this isn't thread-safe
+				context->debugger->state = DEBUGGER_EXITING;
+				break;
+			case SDL_KEYDOWN:
+			case SDL_KEYUP:
+				_GBASDLHandleKeypress(context, &event.key);
+				break;
+			}
 		}
 	}
 }
@@ -123,3 +134,47 @@ free(renderer->d.outputBuffer);
 
 	SDL_Quit();
 }
+
+static void _GBASDLHandleKeypress(struct GBAThread* context, const struct SDL_KeyboardEvent* event) {
+	enum GBAKey key = 0;
+	switch (event->keysym.sym) {
+	case SDLK_z:
+		key = GBA_KEY_A;
+		break;
+	case SDLK_x:
+		key = GBA_KEY_B;
+		break;
+	case SDLK_a:
+		key = GBA_KEY_L;
+		break;
+	case SDLK_s:
+		key = GBA_KEY_R;
+		break;
+	case SDLK_RETURN:
+		key = GBA_KEY_START;
+		break;
+	case SDLK_BACKSPACE:
+		key = GBA_KEY_SELECT;
+		break;
+	case SDLK_UP:
+		key = GBA_KEY_UP;
+		break;
+	case SDLK_DOWN:
+		key = GBA_KEY_DOWN;
+		break;
+	case SDLK_LEFT:
+		key = GBA_KEY_LEFT;
+		break;
+	case SDLK_RIGHT:
+		key = GBA_KEY_RIGHT;
+		break;
+	default:
+		return;
+	}
+
+	if (event->type == SDL_KEYDOWN) {
+		context->activeKeys |= 1 << key;
+	} else {
+		context->activeKeys &= ~(1 << key);
+	}
+}