int 13h return 0x0C80 - PullRequest
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int 13h return 0x0C80

0 голосов
/ 03 октября 2018

Недавно я изучал операционные системы, и в настоящее время я нахожусь в точке чтения секторов с 13h / 0x02.Но когда я запускаю свой код, я получаю следующую ошибку:
Disk read error! 0x0C80
Но проблема нечеткая, и когда я ее ищу, появляется сообщение об ошибке или тип носителя не найден (дискета).Вот соответствующий код:

boot.asm 

[org 0x7c00] ; bootloader offset
KERNEL_OFFSET equ 0x1000

    mov [BOOT_DRIVE], dl    

    mov bp, 0x9000 ; set the stack
    mov sp, bp

    mov bx, MSG_REAL_MODE
    call printf ; This will be written after the BIOS messages

    call load_kernel

    call switch_to_pm
    jmp $ ; this will actually never be executed

%include "/boot/printf.asm"
%include "/boot/diskload.asm"
%include "/boot/printhex.asm"
%include "/32bit-functions/gdt.asm"
%include "/32bit-functions/32bit-print.asm"
%include "/32bit-functions/switch.asm"

[bits 16]

load_kernel:
    mov bx, MSG_LOAD_KERNEL
    call printf

    mov dl, [BOOT_DRIVE]
    mov dh, 0x01
    mov bx, KERNEL_OFFSET
    call diskload

    ret

[bits 32]
BEGIN_PM:
    mov ebx, MSG_PROT_MODE
    call print_string_pm

    call KERNEL_OFFSET ; Give control to the kernel
    jmp $ ; Stay here when the kernel returns control to us (if ever)

BOOT_DRIVE db 0 ; It is a good idea to store it in memory because 'dl' may get
                   ;overwritten
MSG_REAL_MODE db "Started in 16-bit Real Mode", 0
MSG_PROT_MODE db "Landed in 32-bit Protected Mode", 0
MSG_LOAD_KERNEL db "Loading kernel into memory", 0

; bootsector
times 510-($-$$) db 0
dw 0xaa55

diskload.asm 

; load 'dh' sectors from drive 'dl' into ES:BX
diskload:
    pusha
    ; reading from disk requires setting specific values in all registers
    ; so we will overwrite our input parameters from 'dx'. Let's save it
    ; to the stack for later use.
    push dx

    mov ch, 0x00 ; ch <- cylinder (0x0 .. 0x3FF, upper 2 bits in 'cl')
    ; dl <- drive number. Our caller sets it as a parameter and gets it from BIOS
    ; (0 = floppy, 1 = floppy2, 0x80 = hdd, 0x81 = hdd2)
    mov cl, 0x02 ; cl <- sector (0x01 .. 0x11)
    mov ah, 0x02 ; ah <- int 0x13 function. 0x02 = 'read'
    mov al, dh   ; al <- number of sectors to read (0x01 .. 0x80)
                 ; 0x01 is our boot sector, 0x02 is the first 'available' sector
    mov dh, 0x00 ; dh <- head number (0x0 .. 0xF)

    mov es, bx

    ; [es:bx] <- pointer to buffer where the data will be stored
    ; caller sets it up for us, and it is actually the standard location for int 13h
    int 0x13      ; BIOS interrupt
    jc disk_error ; if error (stored in the carry bit)

    pop dx
    cmp al, dh    ; BIOS also sets 'al' to the # of sectors read. Compare it.
    jne sectors_error
    popa
    ret


disk_error:
    mov bx, DISK_ERROR
    call printf
    call print_nl
    mov dh, ah ; ah = error code, dl = disk drive that dropped the error
    call printhex ; check out the code at http://stanislavs.org/helppc/int_13-1.html
    jmp disk_loop

sectors_error:
    mov bx, SECTORS_ERROR
    call printf

disk_loop:
    jmp $


DISK_ERROR: db "Disk read error", 0
SECTORS_ERROR: db "Incorrect number of sectors read", 0

Я не совсемуверен, что я сделал не так.И я потратил некоторое время на поиск ответа

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