主页 / user-28805909

Bob Dude's questions

Martin Hope
Bob Dude
Asked: 2024-12-16 21:42:04 +0800 CST
  • 5

这个问题已经解决了！！！我已经更新了引导加载程序和内核代码，以匹配已修复的代码，以便任何遇到相同问题的操作系统制造商（可能很快会在内核中添加评论）。以下是 Nate Eldredge 编写的修复代码的解释。无关，但操作系统最初称为 POVESK。结果发现已经有这样的名字，所以现在在引导加载程序代码中进行了更改。

最近在做一个操作系统，在制作GDT的时候遇到了很大的问题

内核代码（这就是我拼写内核的方式）：

[org 0x8000]
[bits 16]

jmp short start

%define ENDL 0x0D, 0x0A

gdt_start:
    dq 0x0000000000000000

    dq 0x00CF9A000000FFFF
    dq 0x00CF92000000FFFF

    dq 0x00CF92000000FFFF

gdt_end:

gdt_descriptor:
    dw gdt_end - gdt_start - 1
    dd gdt_start

print:
    push si
    push ax
    push bx

.loop:
    lodsb
    or al, al
    jz .done

    mov ah, 0x0E
    mov bh, 0
    int 0x10

    jmp .loop

.done:
    pop bx
    pop ax
    pop si    
    ret

start:
    mov si, start_sixteen
    call print

    in al, 0x64
.wait_ibe:
    test al, 0x02
    jnz .wait_ibe
    mov al, 0xD1
    out 0x64, al
.wait_ibe2:
    in al, 0x64
    test al, 0x02
    jnz .wait_ibe2
    mov al, 0xDF
    out 0x60, al

first_sixteen:
    mov ah, 0x00
    mov al, 0x03
    int 0x10

    cli
    lgdt [gdt_descriptor]

    mov eax, cr0
    or eax, 1
    mov cr0, eax

    jmp dword 0x08:.afterstart

[bits 32]

VIDEO_MEMORY equ 0xb8000
WHITE_ON_BLACK equ 0x0f

.afterstart:
    mov ax, 0x10
    mov ds, ax
    mov es, ax
    mov fs, ax
    mov gs, ax
    mov ss, ax

    mov ebx, start_thirty_two
    call print32

    cli
    hlt

    jmp short start_prog

print32:
    pusha
    mov edx, VIDEO_MEMORY
.loop:
    mov al, [ebx]
    mov ah, WHITE_ON_BLACK
    cmp al, 0
    je .done
    mov [edx], ax
    add ebx, 1
    add edx, 2
    jmp .loop
.done:
    popa
    ret

start_prog:
    mov al, 2
    mov eax, 1004
    mov [Xval], eax
    mov eax, 50
    mov [Yval], eax
    mov eax, 10
    mov [Wval], eax
    mov eax, 20
    mov [Hval], eax
    lea esi, [PySpr]
    
    call draw_spr

.halt:
    cli
    hlt

draw_spr:
    xor edx, edx
    mov ecx, [Hval]
draw_sprite:
    mov eax, [Yval]
    mov ebx, 1024
    mul ebx
    add eax, [Xval]
    mov edi, eax
    push ecx
    mov ecx, [Wval]
draw_pixels:
    mov al, [esi]
    cmp al, 5
    je skip_pixel_2
    stosd
    jmp skip_pixel
skip_pixel_2:
    inc edi
skip_pixel:
    inc esi
    loop draw_pixels
    pop ecx
    mov eax, [Yval]
    inc eax
    mov [Yval], eax
    loop draw_sprite
    ret

start_sixteen: db 'STAGE ONE START', ENDL, 0
start_thirty_two: db 'STAGE TWO START', 0

Xval dd 0
Yval dd 0
Wval dd 0
Hval dd 0

PySpr db 5,5,5,2,2,2,2,5,5,5
      db 5,5,2,2,2,2,2,2,5,5
      db 5,2,2,2,2,2,2,2,2,5
      db 2,2,2,2,2,2,2,2,2,2
      db 5,8,8,8,8,8,8,8,8,5
      db 5,8,15,0,8,8,0,15,8,5
      db 5,8,8,8,8,8,8,8,8,5
      db 5,8,8,0,0,0,0,8,8,5
      db 5,5,8,8,8,8,8,8,5,5
      db 2,2,2,2,2,2,2,2,2,2
      db 2,2,2,2,2,2,2,2,2,2
      db 2,5,2,2,2,2,2,2,5,2
      db 2,5,2,2,2,2,2,2,5,2
      db 2,5,2,2,2,2,2,2,5,2
      db 8,5,2,2,2,2,2,2,5,8
      db 5,5,6,6,6,6,6,6,5,5
      db 5,5,6,6,5,5,6,6,5,5
      db 5,5,6,6,5,5,6,6,5,5
      db 5,5,6,6,5,5,6,6,5,5
      db 5,7,7,7,5,5,7,7,7,5

引导加载程序代码（基本上是第 3 部分的 nanobyte os 引导加载程序，但略有改动）：

[org 0x7C00]
[bits 16]

%define ENDL 0x0D, 0x0A

jmp short start
nop

bdb_oem:                    db 'CLIPIN..'
bdb_bytes_per_sector:       dw 512
bdb_sectors_per_cluster:    db 1
bdb_reserved_sectors:       dw 1
bdb_fat_count:              db 2
bdb_dir_entries_count:      dw 0E0h
bdb_total_sectors:          dw 2880
bdb_media_descriptor_type:  db 0F0h
bdb_sectors_per_fat:        dw 9
bdb_sectors_per_track:      dw 18
bdb_heads:                  dw 2
bdb_hidden_sectors:         dd 0
bdb_large_sector_count:     dd 0

ebr_drive_number:           db 0
                            db 0
ebr_signature:              db 29h
ebr_volume_id:              db 12h, 34h, 56h, 78h
ebr_volume_label:           db 'CLIPIN.. OS'
ebr_system_id:              db 'FAT12   '

start:
    xor ax, ax
    mov ds, ax
    mov es, ax
    mov ss, ax
    mov sp, 0x7C00
    push es
    push word .after
    retf

.after:
    mov [ebr_drive_number], dl
    mov si, msg_loading
    call puts
    push es
    mov ah, 08h
    int 13h
    jc floppy_error
    pop es
    and cl, 0x3F
    xor ch, ch
    mov [bdb_sectors_per_track], cx
    inc dh
    mov [bdb_heads], dh
    mov ax, [bdb_sectors_per_fat]
    mov bl, [bdb_fat_count]
    xor bh, bh
    mul bx
    add ax, [bdb_reserved_sectors]
    push ax
    mov ax, [bdb_dir_entries_count]
    shl ax, 5
    xor dx, dx
    div word [bdb_bytes_per_sector]
    test dx, dx
    jz .root_dir_after
    inc ax

.root_dir_after:
    mov cl, al
    pop ax
    mov dl, [ebr_drive_number]
    mov bx, buffer
    call disk_read
    xor bx, bx
    mov di, buffer

.search_kernal:
    mov si, file_kernal_bin
    mov cx, 11
    push di
    repe cmpsb
    pop di
    je .found_kernal
    add di, 32
    inc bx
    cmp bx, [bdb_dir_entries_count]
    jl .search_kernal
    jmp kernal_not_found_error

.found_kernal:
    mov ax, [di + 26]
    mov [kernal_cluster], ax
    mov ax, [bdb_reserved_sectors]
    mov bx, buffer
    mov cl, [bdb_sectors_per_fat]
    mov dl, [ebr_drive_number]
    call disk_read
    mov bx, kernal_LOAD_SEGMENT
    mov es, bx
    mov bx, kernal_LOAD_OFFSET

.load_kernal_loop:
    mov ax, [kernal_cluster]
    add ax, 31
    mov cl, 1
    mov dl, [ebr_drive_number]
    call disk_read
    add bx, [bdb_bytes_per_sector]
    mov ax, [kernal_cluster]
    mov cx, 3
    mul cx
    mov cx, 2
    div cx
    mov si, buffer
    add si, ax
    mov ax, [ds:si]
    or dx, dx
    jz .even

.odd:
    shr ax, 4
    jmp .next_cluster_after

.even:
    and ax, 0x0FFF

.next_cluster_after:
    cmp ax, 0x0FF8
    jae .read_finish
    mov [kernal_cluster], ax
    jmp .load_kernal_loop

.read_finish:
    mov dl, [ebr_drive_number]
    mov ax, kernal_LOAD_SEGMENT
    mov ds, ax
    mov es, ax
    jmp kernal_LOAD_SEGMENT:kernal_LOAD_OFFSET
    jmp wait_key_and_reboot
    cli
    hlt

floppy_error:
    mov si, msg_read_failed
    call puts
    jmp wait_key_and_reboot

kernal_not_found_error:
    mov si, msg_kernal_not_found
    call puts
    jmp wait_key_and_reboot

wait_key_and_reboot:
    xor ah, ah
    int 16h
    jmp 0FFFFh:0

.halt:
    cli
    hlt

puts:
    push si
    push ax
    push bx

.loop:
    lodsb
    or al, al
    jz .done
    mov ah, 0x0E
    xor bh, bh
    int 0x10
    jmp .loop

.done:
    pop bx
    pop ax
    pop si    
    ret

lba_to_chs:
    push ax
    push dx
    xor dx, dx
    div word [bdb_sectors_per_track]
    inc dx
    mov cx, dx
    xor dx, dx
    div word [bdb_heads]
    mov dh, dl
    mov ch, al
    shl ah, 6
    or cl, ah
    pop ax
    mov dl, al
    pop ax
    ret

disk_read:
    push ax
    push bx
    push cx
    push dx
    push di
    push cx
    call lba_to_chs
    pop ax
    mov ah, 02h
    mov di, 3

.retry:
    pusha
    stc
    int 13h
    jnc .done
    popa
    call disk_reset
    dec di
    test di, di
    jnz .retry

.fail:
    jmp floppy_error

.done:
    popa
    pop di
    pop dx
    pop cx
    pop bx
    pop ax
    ret

disk_reset:
    pusha
    xor ah, ah
    stc
    int 13h
    jc floppy_error
    popa
    ret

msg_loading:            db 'BOOT START', ENDL, 0
msg_read_failed:        db 'FAIL READ DISK', ENDL, 0
msg_kernal_not_found:   db 'KERNAL NOT FOUND', ENDL, 0
file_kernal_bin:        db 'KERNAL  BIN'
kernal_cluster:         dw 0

kernal_LOAD_SEGMENT     equ 0x0000
kernal_LOAD_OFFSET      equ 0x8000

times 510-($-$$) db 0
dw 0AA55h

buffer:

问题出在内核代码中。我进行了一些调试，并确定这可能是由于三重错误（chatGPT 得出的结论）造成的，并且它通常发生在 jmp dword 0x08:.afterstart 中，但奇怪的是，在多次尝试修复此问题后（找到许多教程和项目并将它们修复到我的代码中），三重错误出现在许多不同的代码行中。我在这个主题上相当缺乏经验，所以我可能真的很笨，错过了一些显而易见的东西。

如果有人有解决方案请告诉我。提前谢谢！

三重失误jmp dword 0x08:.afterstart，并已开始出现在许多其他线路中。

构建命令：

--WinCMD NASM
nasm scr/boot.asm -f bin -o build/boot.bin
nasm scr/kernal.asm -f bin -o build/kernal.bin
--WSL
dd if=/dev/zero of=v_004.img bs=512 count=2880
mkfs.fat -F 12 -n NBOS v_004.img
dd if=boot.bin of=v_004.img conv=notrunc 
mcopy -i v_004.img kernal.bin ::kernal.bin
--QEMUCMD
qemu-system-x86_64 v_004.img
assembly