Re: Compiling grub2 on *BSD?

[Bean]

On Jan 27, 2008 2:15 AM, Bean <address@hidden> wrote:
> On Jan 27, 2008 1:21 AM, Robert Millan <address@hidden> wrote:
> > > FreeBSD:
> > >
> > > lnxboot.S: Assembler messages:
> > > lnxboot.S:49: Error: `0x200+data_start - data_next(%ebx,%eax)' is not a
> > > valid 16 bit base/index expression
> > > lnxboot.S:264: Error: `(%esi,%eax)' is not a valid 16 bit base/index
> > > expression
> > > lnxboot.S:265: Error: `(%edi,%eax)' is not a valid 16 bit base/index
> > > expression
> >
> > I recall having seen this before.  Please, can you check the list archives?
> > I think we solved it for other files, but it might have been respawned in
> > lnxboot.S.
>
> yes, this is caused by a trick to use 32-bit address mode for fast
> arithmetic. here is the patch, along with some code cleanup for
> lnxboot.S.
>
> diff --git a/boot/i386/pc/lnxboot.S b/boot/i386/pc/lnxboot.S
> index f1a4ded..81d8e40 100644
> --- a/boot/i386/pc/lnxboot.S
> +++ b/boot/i386/pc/lnxboot.S
> @@ -36,22 +36,7 @@
>          .globl  start, _start
>
>  data_start:
> -       pushw   %cs
> -       popw    %ds
> -       xorl    %eax, %eax
> -       xorl    %ebx, %ebx
> -       call    data_next
> -
> -data_next:
> -       popw    %bx
> -       movw    %cs, %ax
> -       shll    $4, %eax
> -       leal    0x200 + data_start - data_next(%ebx,%eax), %eax
> -       movzbl  setup_sects - data_next(%bx), %ecx
> -       shll    $9, %ecx
> -       addl    %ecx, %eax
> -       movl    %eax, code32_start - data_next(%bx)
> -
> +       xorl    %ebp, %ebp
>         jmp     linux_next
>
>         . = data_start + 0x1F1
> @@ -76,7 +61,7 @@ boot_flag:
>  start:
>  _start:
>
> -       jmp linux_code
> +       jmp linux_init
>
>         .ascii  "HdrS"                  // Header signature
>         .word   0x0203                  // Header version number
> @@ -134,9 +119,10 @@ reg_edx:
>  data_leng:
>         .long   0
>
> -linux_code:
> +linux_init:
>
>         movw    %cs:(reg_edx - start), %dx
> +       movl    %cs:(code32_start - start), %ebp
>
>  linux_next:
>
> @@ -164,9 +150,6 @@ real_code:
>         movw    %si, %ss
>         movw    $(CODE_ADDR), %sp
>
> -       pushl   %esi
> -       pushl   %edi
> -
>         // Move itself to 0:CODE_ADDR
>
>         cld
> @@ -183,34 +166,45 @@ real_code:
>
>  real_code_2:
>
> -       pushw   %es
> -       popw    %ds
> -
> -       movl    (ramdisk_image - start), %esi
> -       or      %esi, %esi
> +       xchgl   %ebp, %esi
> +       orl     %esi, %esi
>         jnz     1f
> -       movl    (code32_start - start), %esi
> +       movw    %ds, %si
> +       shll    $4, %esi
> +       addl    %ebp, %esi
>  1:
>
> +       pushw   %es
> +       popw    %ds
> +
>         movl    $0x200, %ecx
>         addl    %ecx, %esi
>         movl    $DATA_ADDR, %edi
>
>         call    move_memory
>
> -       movsbl  %dh, %eax
> -       movl    %eax, %ss:(DATA_ADDR + GRUB_KERNEL_MACHINE_INSTALL_DOS_PART)
> +       // Check for the multiboot signature
> +       cmpl    $0x1badb002, %ss:(DATA_ADDR + 0x50)
> +       jz      1f
>
> -       movsbl  (reg_edx + 2 - start), %eax
> -       movl    %eax, %ss:(DATA_ADDR + GRUB_KERNEL_MACHINE_INSTALL_BSD_PART)
> +       movl    (ramdisk_image - start), %esi
> +       movl    (ramdisk_size - start), %ecx
> +       movl    $(DATA_ADDR - 0x200), %edi
> +       jmp     2f
> +
> +1:
>
>         movl    %ss:(DATA_ADDR + GRUB_KERNEL_MACHINE_COMPRESSED_SIZE), %ecx
>         addl    $(GRUB_KERNEL_MACHINE_RAW_SIZE - 0x200), %ecx
>
> +2:
>         call    move_memory
>
> -       popl    %edi
> -       popl    %esi
> +       movsbl  %dh, %eax
> +       movl    %eax, %ss:(DATA_ADDR + GRUB_KERNEL_MACHINE_INSTALL_DOS_PART)
> +
> +       movsbl  (reg_edx + 2 - start), %eax
> +       movl    %eax, %ss:(DATA_ADDR + GRUB_KERNEL_MACHINE_INSTALL_BSD_PART)
>
>         ljmp    $(DATA_ADDR >> 4), $0
>
> @@ -261,8 +255,8 @@ move_memory:
>
>  2:
>
> -       leal    (%esi, %eax), %esi
> -       leal    (%edi, %eax), %edi
> +       addl    %eax, %esi
> +       addl    %eax, %edi
>         subl    %eax, %ecx
>         jnz     1b
>
>
>
>
> --
> Bean
>

if there is no objection, I'd like to check in this patch.

-- 
Bean