#
# bimage
# 
# 0 ---------> +-----------------------------+ <--------+
#              |                             |          |
#              |           unused            |          |
#              |                             |          |
# 497 -------> +-----------------------------+          | bbootsect
#              |                             |          |
#              |    linux header part 1      |          |
#              |                             |          |
# 512 -------> +-----------------------------+ <--------+
#              |                             |          |
#              |    linux header part 2      |          |
#              |                             |          |
#              +-----------------------------+          | bsetup
#              |                             |          |
#              |         jos64 init          |          |
#              |                             |          |
# ELFOFF ----> +-----------------------------+ <--------+
#              |                             |
#              |       jos64 kernel ELF      |
#              |                             |
#              +-----------------------------+
#

# Must be a multiple of 512 and fit bbootsect and bsetup
ELFOFF := 4096

OBJDIRS += boot

BBS_OBJS := $(OBJDIR)/boot/bsdata.o
SETUP_OBJS := $(OBJDIR)/boot/setup.o $(OBJDIR)/boot/csetup.o
BOOT_CFLAGS := -m32 -DCODE32 -g -Os -MD -Wall -Werror -DJOS_KARCH_$(K_ARCH) \
	       -DELFOFF=$(ELFOFF)

$(OBJDIR)/boot/%.o: boot/%.S boot/Makefrag
	@mkdir -p $(@D)
	$(CC) $(BOOT_CFLAGS) $(INCLUDES) -c -o $@ $<

$(OBJDIR)/boot/%.o: boot/%.c boot/Makefrag
	$(CC) $(BOOT_CFLAGS) $(INCLUDES) $(CSTD) -c -o $@ $<

$(OBJDIR)/boot/bbootsect: $(BBS_OBJS)
	$(LD) -melf_i386 -N -e start -o $@.out -Ttext 0x7C00 $(BBS_OBJS) \
	      -Tdata 0x7DF0
	$(OBJCOPY) -S -O binary $@.out $@	
	perl boot/pad.pl $@ 512

# Build the bootstrap code for mp systems
$(OBJDIR)/boot/bootother: $(OBJDIR)/boot/bootother.o
	$(LD) -melf_i386 -N -e start -Ttext 0x7000 -o $(OBJDIR)/boot/bootother.out $<
	$(OBJCOPY) -S -O binary $(OBJDIR)/boot/bootother.out $@

# For Linux setup code, link at 0x0, but load address is irrelevant
$(OBJDIR)/boot/bsetup: $(SETUP_OBJS)
	$(LD) -melf_i386 -N -e start -o $@.out -Ttext 0x0 $^
	$(OBJCOPY) -S -O binary $@.out $@
	perl boot/pad.pl $@ $(shell echo $$(($(ELFOFF) - 512)))

$(OBJDIR)/boot/bimage.%: $(OBJDIR)/boot/bbootsect $(OBJDIR)/boot/bsetup \
			 $(OBJDIR)/kern/kernel.%
	cat $^ > $@

# Build the Bochs disk image
$(OBJDIR)/boot/bochs.img: $(OBJDIR)/boot/bimage.init $(OBJDIR)/boot/bimage.base boot/syslinux.cfg
	dd if=/dev/zero of=$@~ bs=1024k count=128 2>/dev/null
	mkdosfs $@~
	syslinux $@~
	echo "drive z: file=\"$@~\"" > $@.mtoolsrc
	MTOOLSRC=$@.mtoolsrc mcopy $(OBJDIR)/boot/bimage.base z:histar.ker
	MTOOLSRC=$@.mtoolsrc mcopy $(OBJDIR)/boot/bimage.init z:histar.ini
	MTOOLSRC=$@.mtoolsrc mcopy boot/syslinux.cfg z:syslinux.cfg
	mv $@~ $@

# Build a pstate disk with a partition table
$(OBJDIR)/fs/fs.img:
	@mkdir -p $(@D)
	dd if=/dev/zero of=$@~ bs=1024k count=512 2>/dev/null
	perl boot/partinit.pl $@~
	mv $@~ $@

# Build a bootable iso
$(OBJDIR)/boot/boot.iso: IMAGE_CMDLINE = default histar
$(OBJDIR)/boot/boot.iso: $(OBJDIR)/boot/bimage.init
	-rm -rf $(@D)/isoimage
	@mkdir -p $(@D)/isoimage
	cp boot/isolinux.bin $(@D)/isoimage/isolinux.bin
	cp $(OBJDIR)/boot/bimage.init $(@D)/isoimage/histar
	echo '$(IMAGE_CMDLINE)' > $(@D)/isoimage/isolinux.cfg
	mkisofs -J -r -o $@ -b isolinux.bin -c boot.cat \
		-no-emul-boot -boot-load-size 4 -boot-info-table \
		$(@D)/isoimage