lesson 14

14-checkpoint/Makefile

@@ -1,17 +1,20 @@
 C_SOURCES = $(wildcard kernel/*.c drivers/*.c)
 HEADERS = $(wildcard kernel/*.h drivers/*.h)
+# Nice syntax for file extension replacement
 OBJ = ${C_SOURCES:.c=.o}
 
 # Change this if your cross-compiler is somewhere else
 CC = /usr/local/i386elfgcc/bin/i386-elf-gcc
 GDB = /usr/local/i386elfgcc/bin/i386-elf-gdb
-# -g: Use debugging symbols
+# -g: Use debugging symbols in gcc
 CFLAGS = -g
 
 # First rule is run by default
 os-image.bin: boot/bootsect.bin kernel.bin
 	cat $^ > os-image.bin
 
+# '--oformat binary' deletes all symbols as a collateral, so we don't need
+# to 'strip' them manually on this case
 kernel.bin: boot/kernel_entry.o ${OBJ}
 	i386-elf-ld -o $@ -Ttext 0x1000 $^ --oformat binary
 
@@ -22,22 +25,22 @@ kernel.elf: boot/kernel_entry.o ${OBJ}
 run: os-image.bin
 	qemu-system-i386 -fda os-image.bin
 
+# Open the connection to qemu and load our kernel-object file with symbols
 debug: os-image.bin kernel.elf
 	qemu-system-i386 -s -fda os-image.bin &
 	${GDB} -ex "target remote localhost:1234" -ex "symbol-file kernel.elf"
 
+# Generic rules for wildcards
 # To make an object, always compile from its .c
 %.o: %.c ${HEADERS}
 	${CC} ${CFLAGS} -ffreestanding -c $< -o $@
 
-# Object files from asm files
 %.o: %.asm
 	nasm $< -f elf -o $@
 
 %.bin: %.asm
 	nasm $< -f bin -o $@
 
-
 clean:
 	rm -rf *.bin *.dis *.o os-image.bin *.elf
 	rm -rf kernel/*.o boot/*.bin drivers/*.o