fixed sample boot.asm, changed Makefile target to $(ISO)

git-svn-id: svn://anubis/hos/trunk@6 5b3e749e-e535-0410-8002-a9bb6afbdfca

Makefile

@@ -4,7 +4,7 @@ MKISOFS = genisoimage
 ISO = $(HOS).iso
 QEMU = qemu-system-x86_64
 
-.PHONY: kernel iso clean qemu
+.PHONY: kernel clean qemu
 
 # default target: build the kernel and ISO image
 all: kernel iso
@@ -14,7 +14,7 @@ kernel:
 	make -C kernel
 
 # build the ISO image
-iso: kernel
+$(ISO): kernel
 	cp kernel/$(HOS) iso/boot
 	$(MKISOFS) -R -b boot/grub/stage2_eltorito -no-emul-boot \
 		-boot-load-size 4 -boot-info-table -o $(ISO) iso
@@ -23,5 +23,5 @@ clean:
 	make -C kernel clean
 	-rm -f $(ISO) iso/boot/$(HOS)
 
-qemu:
+qemu: $(ISO)
 	$(QEMU) -cdrom $(ISO) -boot d -m 384 -localtime