disk_read: push dx ; store dx on stack so that we can compare later mov ah, BIOS_DISK_READ ; specify function mov al, dh ; read dh amount of sectors mov ch, 0x00 ; CYLINDER mov dh, 0x00 ; HEAD mov cl, 0x02 ; SECTOR int BIOS_DISK_INT ; interrupt ; Error checks jc read_error ; carry flag set -> error pop dx cmp dh, al ; if dh != al then error jne sector_error ret sector_error: mov bx, sector_error_string call println read_error: ; Inform the user mov bx, read_error_string call println ; Print the error mov bx, error_code_string call print mov dh, ah call print_hex mov bx, [ASCII_END] call println jmp $ read_error_string: db ASCII_CARRIAGE_RETURN, ASCII_LINEBREAK, "ERROR! Disk read failed.", ASCII_END error_code_string: db "Error code: ", ASCII_END sector_error_string: db "Invalid number of sectors read!", ASCII_END