Makefile

Jeko · Post by **Jeko** » Wed Jan 30, 2008 2:54 pm

I'm rewriting my kernel from 0 because I want to do it better than before.

Now I'm making a more clean Makefile:

KERNEL_NAME := jeko.img

CC := ccache gcc
AS := nasm
LD := ld

PROJDIRS := .

CFILES := $(shell find $(PROJDIRS) -mindepth 1 -maxdepth 3 -name "*.c")
ASMFILES := $(shell find $(PROJDIRS) -mindepth 1 -maxdepth 3 -name "*.asm")
OBJFILES := $(shell find $(PROJDIRS) -mindepth 1 -maxdepth 3 -name "*.o")

CFLAGS := -Wall -O -floop-optimize2 -fno-builtin -nostdlib -nostartfiles -nodefaultlibs -nostdinc -I include -ffreestanding -fno-stack-protector
LDFLAGS := -Tlink.ld -o $(KERNEL_NAME)
ASFLAGS := -felf

all: $(KERNEL_NAME)

install:
	mount /floppy/
	cp $(KERNEL_NAME) /floppy/

	umount /floppy/

clean:
	rm $(OBJFILES)

%.o: %.asm

	$(AS) $(ASFLAGS) -o $@ $<



%.o: %.c

	$(CC) $(CFLAGS) -c $< -o $@



$(KERNEL_NAME): $(OBJFILES)	

	$(LD) $(LDFLAGS) $(OBJFILES)

but it doesn't work. Why?

Zenith · Post by **Zenith** » Wed Jan 30, 2008 5:19 pm

In what way doesn't it work? Can you show us the error message make produces?

djenkins75 · Post by **djenkins75** » Wed Jan 30, 2008 7:25 pm

I would suspect that "OBJFILES" is empty if they have not already been built.

Therefore, "KERNEL_NAME" has no dependencies, so none of the objects get built.

I would suggest defining OBJFILES some other way. Make supports a method for renaming the extension of the strings contained within a variable. I forget the exact syntax, but something like this:

OBJILES:= $(ASMFILES:=.o) $(CFILES:=.o)

except the above is incorrect. It will add ".o" to each file instead of replacing ".c" or ".asm" with ".o". But there is a way to do it.

Exercise left to the OP.

pcmattman · Post by **pcmattman** » Thu Jan 31, 2008 12:06 am

patsubst, ie:

Code: Select all

$OBJS=$(patsubst %.c,%.o,$(SRCS))

Read Solar's makefile tutorial on the wiki.

Jeko · Post by **Jeko** » Mon Feb 04, 2008 4:30 pm

Code: Select all

KERNEL_NAME := jeko.img

CC := ccache gcc
AS := nasm
LD := ld

PROJDIRS := .

CFILES := $(shell find $(PROJDIRS) -mindepth 1 -maxdepth 3 -name "*.c")
ASMFILES := $(shell find $(PROJDIRS) -mindepth 1 -maxdepth 3 -name "*.asm")
OBJFILES := $(patsubst %.c, %.o, $(CFILES))

CFLAGS := -Wall -O -floop-optimize2 -fno-builtin -nostdlib -nostartfiles -nodefaultlibs -nostdinc -I include -ffreestanding -fno-stack-protector
LDFLAGS := -Tlink.ld -o $(KERNEL_NAME)
ASFLAGS := -felf

all: $(KERNEL_NAME)

install:
	mount /floppy/
	cp $(KERNEL_NAME) /floppy/

	umount /floppy/

clean:
	rm $(OBJFILES)

%.o: %.asm

	$(AS) $(ASFLAGS) -o $@ $<



%.o: %.c

	$(CC) $(CFLAGS) -c $< -o $@



$(KERNEL_NAME): $(OBJFILES)	

	$(LD) $(LDFLAGS) $(OBJFILES)

This is my new Makefile, but it doesn't work. At least for ASM files.

How can I do the makefile to work also with asmfiles?
(I think I must change OBJFILES := $(patsubst %.c, %.o, $(CFILES)), because it takes only $(CFILES). But how must I do it?

djenkins75 · Post by **djenkins75** » Mon Feb 04, 2008 5:08 pm

OBJFILES := $(patsubst %.c, %.o, $(CFILES)) $(patsubst %.asm, %.o, $(ASMFILES))

Just concatenate the patsubst together.

Jeko · Post by **Jeko** » Tue Feb 05, 2008 1:00 pm

Ok now it works. But I have a question. How can I use GRUB in order to boot my operating system?
I read this, but if my makefile become this:

Code: Select all

KERNEL_NAME := jeko.img

CC := ccache gcc
AS := nasm
LD := ld

PROJDIRS := .

CFILES := $(shell find $(PROJDIRS) -mindepth 1 -maxdepth 3 -name "*.c")
ASMFILES := $(shell find $(PROJDIRS) -mindepth 1 -maxdepth 3 -name "*.asm")
OBJFILES := $(patsubst %.c, %.o, $(CFILES)) $(patsubst %.asm, %.o, $(ASMFILES))

CFLAGS := -Wall -O -floop-optimize2 -fno-builtin -nostdlib -nostartfiles -nodefaultlibs -nostdinc -I include -ffreestanding -fno-stack-protector
LDFLAGS := -Tlink.ld -o $(KERNEL_NAME)
ASFLAGS := -felf

all: $(KERNEL_NAME)

install:
	mount /floppy/
	cp $(KERNEL_NAME) /floppy/

	umount /floppy/

clean:
	rm $(OBJFILES)

%.o: %.asm

	$(AS) $(ASFLAGS) -o $@ $<



%.o: %.c

	$(CC) $(CFLAGS) -c $< -o $@



$(KERNEL_NAME): $(OBJFILES) barebones bootfloppy.img menu.cfg	

	$(LD) $(LDFLAGS) $(OBJFILES)
	cp bootfloppy.img $@
	chmod +w $@
	mcopy -o -i $@ $< ::/boot
	mcopy -o -i $@ menu.cfg ::/boot

It doesn't work. This is the error message:
ccache gcc -Wall -O -floop-optimize2 -fno-builtin -nostdlib -nostartfiles -nodefaultlibs -nostdinc -I include -ffreestanding -fno-stack-protector -c kernel.c -o kernel.o
nasm -felf -o loader.o loader.asm
ld -Tlink.ld -o jeko.img ./kernel.o ./loader.o
cp bootfloppy.img jeko.img
chmod +w jeko.img
mcopy -o -i jeko.img kernel.o ::/boot
Total number of sectors not a multiple of sectors per track!
Add mtools_skip_check=1 to your .mtoolsrc file to skip this test
make: *** [jeko.img] Error 1

There isn't a better method to work with GRUB?

AJ · Post by AJ » Wed Feb 06, 2008 2:33 am

Hi,

The problem is with you 'mcopy' command line options, not with GRUB or any other part of the toolchain. I've never used mtools, but it may be worth checking out the mcopy documentation - looks like you have to copy over a set number of sectors (at minimum, the bumber of sectors in a track?). Alternatively, use partcopy or another alternative.

Cheers,
Adam

Jeko · Post by **Jeko** » Wed Feb 06, 2008 8:14 am

AJ wrote:Hi,

The problem is with you 'mcopy' command line options, not with GRUB or any other part of the toolchain. I've never used mtools, but it may be worth checking out the mcopy documentation - looks like you have to copy over a set number of sectors (at minimum, the bumber of sectors in a track?). Alternatively, use partcopy or another alternative.

Cheers,
Adam

could you explain me how to use GRUB as my bootloader?

Solar · Post by **Solar** » Wed Feb 06, 2008 8:26 am

How about the GRUB manual?