Seperate compilation of scratch rom

src/board/system76/galp3-c/board.mk

@@ -8,3 +8,37 @@ CFLAGS+=-DLEVEL=2
 
 # Enable I2C debug on 0x76
 # CFLAGS+=-DI2C_DEBUGGER=0x76
+
+# Add scratch ROM source
+SCRATCH_SRC=$(wildcard $(BOARD_DIR)/scratch/*.c)
+SCRATCH_OBJ=$(patsubst src/%.c,$(BUILD)/%.rel,$(SCRATCH_SRC))
+SCRATCH_CC=\
+	sdcc \
+	-mmcs51 \
+	--model-small \
+	--code-size 1024 \
+	--Werror
+
+# Convert from binary file to C header
+$(BUILD)/include/scratch.h: $(BUILD)/scratch.rom
+	@mkdir -p $(@D)
+	xxd --include < $< > $@
+
+# Convert from Intel Hex file to binary file
+$(BUILD)/scratch.rom: $(BUILD)/scratch.ihx
+	@mkdir -p $(@D)
+	makebin -p < $< > $@
+
+# Link object files into Intel Hex file
+$(BUILD)/scratch.ihx: $(SCRATCH_OBJ)
+	@mkdir -p $(@D)
+	$(SCRATCH_CC) -o $@ $^
+
+# Compile C files into object files
+$(SCRATCH_OBJ): $(BUILD)/%.rel: src/%.c
+	@mkdir -p $(@D)
+	$(SCRATCH_CC) -o $@ -c $<
+
+# Require scratch.rom to be compiled before main firmware
+CFLAGS+=-I$(BUILD)/include
+INCLUDE+=$(BUILD)/include/scratch.h