我正在逐步介绍如何从 stratch 构建操作系统。如果有人问，我可以发布 pdf。所以，我有这个“disk_load”调用，它没有明显的原因不起作用。我已经多次检查了每个参数，但它不起作用。
这是代码
test.asm
; Read some sectors from the boot disk using our disk_read function
[org 0x7c00]
mov [BOOT_DRIVE],dl; BIOS stores our boot drive in DL , so it ’s
; best to remember this for later.
mov bp , 0x8000 ; Here we set our stack safely out of the
mov sp , bp ; way , at 0 x8000
mov bx , 0x9000 ; Load 5 sectors to 0 x0000 (ES ):0 x9000 (BX)
mov dh , 5 ; from the boot disk.
mov dl , [BOOT_DRIVE]
call disk_load
mov dx , [0x9000] ; Print out the first loaded word , which
call print_hex ; we expect to be 0xdada , stored
; at address 0 x9000
mov dx , [0x9000 + 512] ; Also , print the first word from the
call print_hex ; 2nd loaded sector : should be 0 xface
jmp $
%include "print_string.asm" ; Re - use our print_string function
%include "print_hex.asm" ; Re - use our print_hex function
%include "disk_load.asm"
; Include our new disk_load function
; Global variables
BOOT_DRIVE: db 0
; Bootsector padding
times 510-($-$$) db 0
dw 0xaa55
; We know that BIOS will load only the first 512- byte sector from the disk ,
; so if we purposely add a few more sectors to our code by repeating some
; familiar numbers , we can prove to ourselfs that we actually loaded those
; additional two sectors from the disk we booted from.
times 256 dw 0xdada
times 256 dw 0xface
disk_load.asm
; load DH sectors to ES:BX from drive DL
disk_load:
push dx ; Store DX on stack so later we can recall
; how many sectors were request to be read ,
; even if it is altered in the meantime
mov ah , 0x02 ; BIOS read sector function
mov al , dh ; Read DH sectors
mov ch , 0x00 ; Select cylinder 0
mov dh , 0x00 ; Select head 0
mov cl , 0x02 ; Start reading from second sector ( i.e.
; after the boot sector )
mov dl, 0x80
int 0x13 ; BIOS interrupt
jc disk_error ; Jump if error ( i.e. carry flag set )
pop dx ; Restore DX from the stack
cmp dh , al ; if AL ( sectors read ) != DH ( sectors expected )
jne disk_error ; display error message
ret
disk_error:
mov bx,DISK_ERROR_MSG
call print_string
mov dl, ah
call print_hex
jmp $
; Variables
DISK_ERROR_MSG db "Disk read error: ", 0
我收到错误消息
Disk read error: 0x000C
，我知道这意味着Media type not found (floppy)
因为print_string并且print_hex做得很好，我不会发布它们。
我已经浏览了每一段代码，对我来说一切都很好。