assembly - Copy and execute -

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i'm writing simple bootloader custom kernel. has simple logic:

  1. bootloader loaded bios.
  2. copy 0x8000.
  3. load kernel disk 0x9000.
  4. jump 0x8000 , copy kernel 0x0 , set gdt.
  5. jump 0x0.

here bootloader:

.set    dest, 0x8000  start: movw    $0x3, %ax int     $0x10  movw    msg, %bp movw    $0xa, %cx call    print_msg  //copy end of bootloader new place selfcopy: cld xor     %ax, %ax movw    %ax, %ds movl    move_kernel, %esi movw    %ax, %es movl    dest, %edi movl    (move_kernel_end-move_kernel), %ecx rep movsb  //load kernel 0x9000 load_kernel: xor     %dx, %dx xor     %ah, %ah int     $0x10 jc      reboot  xor     %ax, %ax movw    %ax, %ds movb    $0x42, %ah movw    dap, %si int     $0x13 jc      reboot  jmp     dest  dap: .byte   0x10 .byte   0x0 .word   2048 //offset .word   9000 .word   0x0 .long   1  move_kernel: xor     %ax, %ax movw    %ax, %ds movl    $0x9000, %esi movw    %ax, %es movl    $0x0, %edi movl    (move_kernel_end-move_kernel), %ecx rep movsb lgdt    gdtr jmp     $0x0 move_kernel_end:  print_msg: //print message     movw    $0x0007, %bx movw    $0x1301, %ax int     $0x10 ret msg: .string "booting..." error_msg: .string "error..."  gdt: .quad   0x0  .byte   0x0 .byte   0b11001111 .byte   0b11111010 .byte   0x0 .word   0x0 .word   0xffff  .byte   0x0 .byte   0b11001111 .byte   0b11110010 .byte   0x0 .word   0x0 .word   0xffff gdtr: .long   gdt .word   $23  reboot: movw    error_msg, %bp movw    $0x8, %cx call    print_msg jmp     .  .fill   510-(. - start), 1, 0 .byte   0x55 .byte   0xaa

so, doesn't work) if put jmp . before jmp dest wouldn't go infinite loop. so, wrong bootloader?

thanks.

p.s. sorry bad english.

modified code:

.set    dest, 0x8000  start: movw    $0x3, %ax int     $0x10  pushw   msg pushw   $0xa call    print_msg  //copy end of bootloader new place selfcopy: cld xor     %ax, %ax movw    %ax, %ds movl    move_kernel, %esi movw    %ax, %es movl    dest, %edi movl    (move_kernel_end-move_kernel), %ecx rep     movsb  //load kernel 0x9000 load_kernel: xor     %dx, %dx xor     %ah, %ah int     $0x13 jc      reboot  xor     %ax, %ax movw    %ax, %ds movb    $0x42, %ah movw    dap, %si int     $0x13 jc      reboot jmp     dest  dap: .byte   0x10 .byte   0x0 .word   2048 //offset .word   9000 .word   0x0 .long   1  move_kernel: cli xor     %ax, %ax movw    %ax, %ds movl    $0x9000, %esi movw    %ax, %es movl    $0x0, %edi movl    (move_kernel_end-move_kernel), %ecx rep movsb lgdt    gdtr jmp     . sti jmp     $0x0 move_kernel_end:  print_msg: //print message popw    %ax popw    %cx popw    %bp pushl   %eax movb    $0x07, %bl movb    $0x13, %ah movb    $0x1, %al int     $0x10 ret  msg: .string "booting..."  gdt: .quad   0x0  .byte   0x0 .byte   0b11001111 .byte   0b11111010 .byte   0x0 .word   0x0 .word   0xffff  .byte   0x0 .byte   0b11001111 .byte   0b11110010 .byte   0x0 .word   0x0 .word   0xffff gdtr: .long   gdt .word   23  reboot: pushw   $0xdead pushw   $0x8 call    print_msg  .fill   510-(. - start), 1, 0 .byte   0x55 .byte   0xaa


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