preliminary LED support (debug port for now; will be I/O line on hardware R2)

Author: mist64

main.c

@@ -1103,6 +1103,9 @@ emulator_loop(void *param)
 			}
 		}
 
+#if 0 // enable this for slow pasting
+		if (!(instruction_counter % 100000))
+#endif
 		while (pasting_bas && RAM[NDX] < 10) {
 			uint32_t c;
 			int e = 0;

memory.c

@@ -20,6 +20,8 @@ uint8_t rom_bank;
 uint8_t *RAM;
 uint8_t ROM[ROM_SIZE];
 
+bool led_status;
+
 #define DEVICE_EMULATOR (0x9fb0)
 
 void
@@ -204,6 +206,7 @@ emu_write(uint8_t reg, uint8_t value)
 		case 3: echo_mode = value; break;
 		case 4: save_on_exit = v; break;
 		case 5: emu_recorder_set((gif_recorder_command_t) value); break;
+		case 15: led_status = v; break;
 		default: printf("WARN: Invalid register %x\n", DEVICE_EMULATOR + reg);
 	}
 }

memory.h

@@ -10,6 +10,8 @@
 #include <stdio.h>
 #include <SDL.h>
 
+extern bool led_status;
+
 uint8_t read6502(uint16_t address);
 uint8_t real_read6502(uint16_t address, bool debugOn, uint8_t bank);
 

video.c

@@ -1056,6 +1056,18 @@ video_update()
 {
 	static bool cmd_down = false;
 
+	// if LED is on, stamp red 8x4 square into top right of framebuffer
+	if (led_status) {
+		for (int y = 0; y < 4; y++) {
+			for (int x = SCREEN_WIDTH - 8; x < SCREEN_WIDTH; x++) {
+				framebuffer[(y * SCREEN_WIDTH + x) * 4 + 0] = 0x00;
+				framebuffer[(y * SCREEN_WIDTH + x) * 4 + 1] = 0x00;
+				framebuffer[(y * SCREEN_WIDTH + x) * 4 + 2] = 0xff;
+				framebuffer[(y * SCREEN_WIDTH + x) * 4 + 3] = 0x00;
+			}
+		}
+	}
+
 	SDL_UpdateTexture(sdlTexture, NULL, framebuffer, SCREEN_WIDTH * 4);
 
 	if (record_gif > RECORD_GIF_PAUSED) {