bootable with small multiboot kernel

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

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
+