Read bytes from boot drive

[nameless-os.git] / boot.s

diff --git a/boot.s b/boot.s
index eb115d0324dd6a2e8e83d94aee9d197d71299392..3a8adc70a9d275e2e17faa53e6772aee0289e36c 100644 (file)
--- a/boot.s
+++ b/boot.s
@@ -1,23 +1,33 @@
        bits 16 ; boot sectors run in real mode
        org 7c00h ; boot sector is loaded at 0x7c00
 
-       mov di, printing_numbers
-       call print
+_start
+       mov [boot_drive], dl ; BIOS sets dl to number of boot drive, we don't want to forget this
 
-       mov dx, 0DEADh ; number to print
-       call print_word
-       mov dx, 0BEEFh
-       call print_word
+       mov bp, 8000h ; Move the stack away
+       mov sp, bp
 
-       mov di, goodbye
-       call print
+       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
 
-       jmp $
+       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
 
-printing_numbers: db "Printing some random hex numbers", 0
-goodbye: db "Thank you for your attention", 0
+       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