Linux x86 bootloader

Linux bzImage从第一个扇区开始存储在磁盘分区sda1上.

我从bzImage(15个扇区)读取实际模式代码到0x7E00开始的内存中.
但是,当我跳入代码时,它只是挂起,没有任何反应.

我已经在sda上为主启动记录创建了代码.如果我只是附上,我可能是最好的
整个东西.我想知道为什么它只是在跳远指令后挂起.

[BITS 16]

%define BOOTSEG 0x7C0 
%define BOOTADDR (BOOTSEG * 0x10)

%define HDRSEG (BOOTSEG + 0x20)
%define HDRADDR (HDRSEG * 0x10)

%define KERNSEG (HDRSEG + 0x20)

[ORG BOOTADDR]
entry_section:
    cli
    jmp     start
start:
    ; Clear segments
    xor     ax,ax
    mov     ds,ax  
    mov     es,ax
    mov     gs,ax
    mov     fs,ax
    mov     ss,ax
    mov     sp,BOOTADDR    ; Lots of room for it to grow down from here

    ; Read all 15 sectors of realmode code in the kernel
    mov     ah,0x42
    mov     si,dap
    mov     dl,0x80
    int     0x13
    jc  bad

    ; Test magic number of kernel header
    mov     eax,dword [HDRADDR + 0x202]
    cmp     eax,'HdrS'
    jne     bad

    ; Test jump instruction is there
    mov     al,byte [KERNSEG * 16]
    cmp     al,0xEB
    jne     bad

    xor     ax,ax      ; Kernel entry code will set ds = ax
    xor     bx,bx      ; Will also set ss = dx
    jmp     dword KERNSEG:0

; Simple function to report an error and halt
bad:
    mov     al,"B"
    call    putc
    jmp     halt

; Param: char in al 
putc:
    mov     ah,0X0E    
    mov     bh,0x0F
    xor     bl,bl  
    int     0x10
    ret

halt:
    hlt
    jmp     halt

; Begin data section
dap:                ; Disk address packet
    db  0x10            ; Size of dap in bytes
    db  0               ; Unused
    dw  15              ; Number of sectors to read
    dw  0               ; Offset where to place data
    dw  HDRSEG          ; Segment where to place data
    dd  0x3F            ; Low order of start addres in sectors
    dd  0               ; High order of start address in sectors

; End data section

times 446-($-$$) db 0   ; Padding to make the MBR 512 bytes

; Hardcoded partition entries
part_boot:
    dw 0x0180,0x0001,0xFE83,0x3c3f,0x003F,0x0000,0xF3BE,0x000E
part_sda2:
    dw 0x0000,0x3D01,0xFFFF,0xF3FD,0x000E,0x5AF0,0x01B3
part_sda3:
    dw 0xFE00,0x4EED,0x01C2,0xb113,0x001D
part_sda4:
    dw 0x0000,0x0000

dw 0xAA55   ; Magic number at relative address 510
mbrend:     ; Relative address 512