X-Git-Url: http://git.dujemihanovic.xyz/posts?a=blobdiff_plain;f=boot.s;h=3a8adc70a9d275e2e17faa53e6772aee0289e36c;hb=d826097f3b032247dd0396f8cf64b2fa775cea68;hp=76880b009eded1d15e93792478061d121a920859;hpb=f9f4f8ebffb463d53ae5a239ddfbe8380f258b8b;p=nameless-os.git

diff --git a/boot.s b/boot.s
index 76880b0..3a8adc7 100644
--- a/boot.s
+++ b/boot.s
@@ -1,18 +1,33 @@
 	bits 16 ; boot sectors run in real mode
 	org 7c00h ; boot sector is loaded at 0x7c00
 
-	mov dx, 0DEADh ; number to print
-	mov cl, 0 ; column
-	mov ch, 0 ; row
-	call print_word
-	mov dx, 0BEEFh
-	mov cl, 0
-	mov ch, 1
+_start
+	mov [boot_drive], dl ; BIOS sets dl to number of boot drive, we don't want to forget this
+
+	mov bp, 8000h ; Move the stack away
+	mov sp, bp
+
+	push cs
+	pop es
+	mov bx, 9000h ; Load at 0000:9000
+	mov dh, 2 ; Load 5 sectors
+	mov dl, [boot_drive] ; Load from boot drive
+	call read_sectors
+
+	mov dx, [9000h] ; Print value at 9000h, should be 0xDEAD
+	call print_word 
+	mov dx, [9000h + 512] ; Print value at 9200h, should be 0xBEEF
 	call print_word
 
-	jmp $
+	jmp $ ; Endless loop
 
 %include "print.s"
+%include "disk.s"
+
+boot_drive resb 1 ; Reserve 1 byte for boot drive number
+
+times 510-($-$$) db 0 ; fill with 0 until 0x1fc is reached
+dw 0AA55h ; BIOS MBR signature
 
-	times 510-($-$$) db 0 ; fill with 0 until 0x1fc is reached
-	dw 0AA55h ; BIOS MBR signature
+times 256 dw 0DEADh ; Fill in 2nd sector with 0xDEAD
+times 256 dw 0BEEFh ; Fill in 3rd sector with 0xBEEF