bootable with small multiboot kernel

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

Makefile

@@ -2,8 +2,9 @@
 HOS = hos
 MKISOFS = genisoimage
 ISO = $(HOS).iso
+QEMU = qemu-system-x86_64
 
-.PHONY: kernel iso clean
+.PHONY: kernel iso clean qemu
 
 # default target: build the kernel and ISO image
 all: kernel iso
@@ -14,9 +15,13 @@ kernel:
 
 # build the ISO image
 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
 
 clean:
 	make -C kernel clean
-	-rm -f $(ISO)
+	-rm -f $(ISO) iso/boot/$(HOS)
+
+qemu:
+	$(QEMU) -cdrom $(ISO) -boot d -m 384 -localtime

iso/boot/grub/menu.lst

@@ -0,0 +1,6 @@
+
+timeout 10
+default 0
+
+title HOS
+kernel /boot/hos

kernel/Makefile

@@ -1,8 +1,12 @@
 
+KERNEL = hos
+TARGET = elf32-i386
+
 .PHONY: clean
 
 all:
-	@echo Nothing yet
+	nasm -f elf -o boot.o boot.asm
+	ld --oformat $(TARGET) -o $(KERNEL) boot.o
 
 clean:
-	@echo Nothing yet
+	-rm -f *~ $(KERNEL) *.o

kernel/boot.asm

@@ -0,0 +1,27 @@
+
+%define MULTIBOOT_HEADER_MAGIC 0x1BADB002
+%define MULTIBOOT_HEADER_FLAGS 0x3
+
+[global start]
+[global _start]
+start:
+_start:
+	jmp	multiboot_entry
+	align 4
+
+multiboot_header:
+	; magic
+	dd	MULTIBOOT_HEADER_MAGIC
+	; flags
+	dd	MULTIBOOT_HEADER_FLAGS
+	; checksum
+	dd	-(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)
+
+multiboot_entry:
+	mov byte [0xB8000+160*10+2*2], 'J'
+	mov byte [0xB8001+160*10+2*2+1], 0x07
+
+looplbl:
+	hlt
+	jmp looplbl
+