Import backup from 2003-08-06

bootsect.asm

@@ -79,7 +79,7 @@ unreal:
 	mov	ebx, cr0
 	inc	bl
 	mov	cr0, ebx	;pmode!
-	mov	ax, 8
+	mov	ax, KERNEL_DATA
 	mov	es, ax
 	mov	ds, ax		;load segment limits
 	dec	bl
@@ -203,7 +203,7 @@ movekernel_loop:
 	cmp	ecx, 0
 	jne	movekernel_loop
 
-	jmp	$
+	jmp	go_pm
 
 ;------------------------------------------------------
 getCHSfromCluster:
@@ -221,36 +221,6 @@ getCHSfromCluster:
 	mov	dh, dl			;head# (0-1)
 	ret
 
-;------------------------------------------------------
-;puthex:
-;	;es:di points to video memory
-;	;al holds hex value
-;
-;	push	ax
-;	mov	ah, al
-;	shr	ax, 4
-;	and	al, 0x0F
-;	add	al, '0'
-;	cmp	al, '9'
-;	jle	puthex_goon1
-;	add	al, 'A'-'9'-1
-;puthex_goon1:
-;	stosb
-;	mov	al, 7
-;	stosb
-;	pop	ax
-;	push	ax
-;	and	al, 0x0F
-;	add	al, '0'
-;	cmp	al, '9'
-;	jle	puthex_goon2
-;	add	al, 'A'-'9'-1
-;puthex_goon2:
-;	stosb
-;	mov	al, 7
-;	stosb
-;	pop	ax
-;	ret
 
 ;-------------------------------------------------------
 gdtr:
@@ -259,8 +229,18 @@ gdtr:
 gdt:
 	dd	0
 	dd	0
+KERNEL_CODE equ $-gdt
+	db	0xff		;limit	7:0
+	db	0xff		;limit	15:8
+	db	0x00		;base	7:0
+	db	0x00		;base	15:8
+	db	0x00		;base	23:16
+	db	0x9a		;access
+	db	0xcf		;flags / limit 19:16
+	db	0x00		;base	31:24
 
-	db	0xff		;segment 8 = 4gb data
+KERNEL_DATA equ $-gdt
+	db	0xff		;segment 16 = 4gb data
 	db	0xff
 	db	0x00
 	db	0x00
@@ -271,12 +251,28 @@ gdt:
 
 gdt_end:
 
+go_pm:
+	xor	ax, ax
+	mov	ds, ax
+	lgdt	[gdtr]
+	cli
+	mov	eax, cr0
+	inc	eax
+	mov	cr0, eax
+
+	jmp	KERNEL_CODE:pmode
+
+bits 32
+pmode:
+	mov	ax, KERNEL_DATA
+	mov	es, ax
+	mov	ds, ax
+	jmp	KERNEL_CODE:KERNEL_ADD
+
 kernel:	db	"KERNEL  BIN"
 k_count: dw	0
 
 times 510-($-$$)	db 0
 
-
-
 db	0x55, 0xaa
 

kernel.asm

@@ -0,0 +1,24 @@
+
+bits 32
+
+org	0x100000
+
+	mov	esi, msg
+	mov	edi, 0xb8000
+
+msg_loop:
+	lodsb
+	or	al, al
+	jz	msg_done
+	stosb
+	mov	al, 15
+	stosb
+	jmp	msg_loop
+
+msg_done:
+
+	jmp	$
+
+msg:
+	db	"This kernel is located at 0x100000!", 0
+