[SC64][SW][DOCS] Reduced bootloader binary size / updated readme

README.md

@@ -15,11 +15,12 @@
  - Status LED and button for general use
  - 64DD add-on emulation
  - IS-Viewer 64 debug interface
- - Software and firmware update via USB interface
  - N64 bootloader with support for IPL3 registers spoofing and loading menu from SD card
  - Enhanced [UltraCIC_C](https://github.com/jago85/UltraCIC_C) emulation with automatic region switching and programmable seed/checksum values
  - PC app for communicating with flashcart (game/save data upload/download, feature enable control and debug terminal)
  - [UNFLoader](https://github.com/buu342/N64-UNFLoader) support
+ - Initial board programming via UART header on board or dedicated JTAG/SWD interfaces
+ - Software and firmware update via USB interface
  - 3D printable plastic shell
 
 ---

sw/bootloader/Makefile

@@ -57,8 +57,8 @@ $(BUILD_DIR)/%.S.o: %.S
 $(BUILD_DIR)/%.c.o: %.c
 	$(CC) $(FLAGS) $(CFLAGS) -c $< -o $@
 
-$(BUILD_DIR)/%.asset: $(ASSET_DIR)/%.png
+$(BUILD_DIR)/%.asset: $(ASSET_DIR)/%.png tools/asset_converter.py
-	$(PYTHON) tools/asset_converter.py $< $@
+	$(PYTHON) tools/asset_converter.py $< $@ --compress
 
 $(BUILD_DIR)/%.asset.o: $(BUILD_DIR)/%.asset $(ASSET_DIR)/assets.S
 	@sed -e "s,@sym@,$*,g" -e "s,@file@,$<," < $(ASSET_DIR)/assets.S | $(CC) -x assembler-with-cpp $(FLAGS) $(ASFLAGS) $(CFLAGS) -c - -o $@
@@ -67,7 +67,7 @@ $(BUILD_DIR)/bootloader.elf: $(OBJS) N64.ld
 	$(CXX) $(FLAGS) $(LDFLAGS) -TN64.ld $(OBJS) -o $@
 	@$(OBJDUMP) -S $@ > $(BUILD_DIR)/bootloader.lst
 
-$(BUILD_DIR)/bootloader.bin: $(BUILD_DIR)/bootloader.elf
+$(BUILD_DIR)/bootloader.bin: $(BUILD_DIR)/bootloader.elf tools/strip.py
 	@$(OBJCOPY) -O binary $< $@
 	@chksum64 $@ > /dev/null
 	@$(PYTHON) tools/strip.py $@

sw/bootloader/src/display.c

@@ -60,6 +60,34 @@ static const vi_regs_t vi_config[] = {{
 }};
 
 
+static void display_decompress_background (uint32_t *background) {
+    uint32_t pixel_count = ((*background++) / sizeof(uint32_t));
+    uint32_t pixels_painted = 0;
+    uint8_t *background_data = (uint8_t *) (background);
+    uint32_t *framebuffer = (uint32_t *) (display_framebuffer);
+
+    while (pixels_painted < pixel_count) {
+        int pixel_repeat = ((background_data[0]) + 1);
+        uint32_t pixel_value = (
+            ((background_data[1]) << 24) |
+            ((background_data[2]) << 16) |
+            ((background_data[3]) << 8) |
+            (background_data[4])
+        );
+        for (int i = 0; i < pixel_repeat; i++) {
+            io_write(framebuffer++, pixel_value);
+        }
+        pixels_painted += pixel_repeat;
+        background_data += 5;
+    }
+}
+
+static void display_clear_background (void) {
+    for (int i = 0; i < (SCREEN_WIDTH * SCREEN_HEIGHT); i++) {
+        io_write(&display_framebuffer[i], BACKGROUND_COLOR);
+    }
+}
+
 static void display_draw_character (char c) {
     if (c == '\n') {
         char_x = BORDER_WIDTH;
@@ -106,14 +134,10 @@ void display_init (uint32_t *background) {
     char_x = BORDER_WIDTH;
     char_y = BORDER_HEIGHT;
 
-    if (background == NULL) {
+    if (background != NULL) {
-        for (int i = 0; i < (SCREEN_WIDTH * SCREEN_HEIGHT); i++) {
+        display_decompress_background(background);
-            io_write(&display_framebuffer[i], BACKGROUND_COLOR);
-        }
     } else {
-        for (int i = 0; i < (SCREEN_WIDTH * SCREEN_HEIGHT); i++) {
+        display_clear_background();
-            io_write(&display_framebuffer[i], *background++);
-        }
     }
 
     io_write(&VI->MADDR, (uint32_t) (display_framebuffer));

sw/bootloader/tools/asset_converter.py

@@ -5,22 +5,53 @@ from PIL import Image
 
 
 
+def compress(data: bytes, step_size: int=4) -> bytes:
+    uncompressed_length = len(data)
+
+    if ((uncompressed_length % step_size) != 0):
+        raise ValueError(f'Data length not aligned to {step_size}')
+
+    compressed_data = bytes()
+    compressed_data += uncompressed_length.to_bytes(4, byteorder='big')
+
+    count = 0
+    last_value = b''
+
+    for offset in range(0, uncompressed_length + step_size, step_size):
+        next_value = data[offset:(offset + step_size)]
+
+        if (offset != 0):
+            if ((next_value == last_value) and (count < 255)):
+                count += 1
+            else:
+                compressed_data += count.to_bytes(1, byteorder='big')
+                compressed_data += last_value
+                count = 0
+
+        last_value = next_value
+
+    return compressed_data
+
+
 if __name__ == "__main__":
-    if (len(sys.argv) != 3):
+    if (len(sys.argv) < 3):
-        print(f"Usage: python {sys.argv[0]} input_path output_path")
+        print(f"Usage: python {sys.argv[0]} input_path output_path [--compress]")
         sys.exit(1)
 
     asset_input = sys.argv[1]
     asset_output = sys.argv[2]
+    asset_compress = len(sys.argv) > 3 and (sys.argv[3] == '--compress')
 
     source_asset = None
     final_asset = None
 
     try:
         source_asset = Image.open(asset_input)
-        converted_asset = source_asset.convert("RGBA")
+        converted_asset = source_asset.convert("RGBA").tobytes()
+        if (asset_compress):
+            converted_asset = compress(converted_asset)
         final_asset = open(asset_output, "wb")
-        final_asset.write(converted_asset.tobytes())
+        final_asset.write(converted_asset)
     except FileNotFoundError:
         print(f"Couldn't open file \"{asset_input}\"")
         sys.exit(2)