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 Using Grub2 with Multiboot2 
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Joined: Wed Sep 01, 2010 4:15 pm
Posts: 2
Post Using Grub2 with Multiboot2
Ok, so i've been tinkering with some assembly language and have successfully booted using grub2 with Multiboot and Multiboot2 specs; however, I have no clue if I am using MULTIBOOT_VIDEO_MODE flag correctly ... or the framebuffer tag for that matter. Supposedly the Multiboot2 header for an elf32 supports setting the video mode:
Code:
struct multiboot_header
{
  /* Must be MULTIBOOT_MAGIC - see above.  */
  multiboot_uint32_t magic;

  /* Feature flags.  */
  multiboot_uint32_t flags;

  /* The above fields plus this one must equal 0 mod 2^32. */
  multiboot_uint32_t checksum;

  /* These are only valid if MULTIBOOT_VIDEO_MODE is set.  */
  multiboot_uint32_t mode_type;
  multiboot_uint32_t width;
  multiboot_uint32_t height;
  multiboot_uint32_t depth;
};


Here is my Multiboot2 header

Code:
.set MB_FLAGS, MULTIBOOT_VIDEO_MODE

.align 8 /* Align 64 bits boundary. */
multiboot_header: /* Multiboot header. */
   .long MULTIBOOT2_HEADER_MAGIC /* magic */
   .long MB_FLAGS
   .long -( MULTIBOOT2_HEADER_MAGIC + MB_FLAGS )
address_tag_end:
framebuffer_tag_start:
   .long 1
   .long 1024
   .long 768
   .long 16
framebuffer_tag_end:
   .long 0 // To make it even
multiboot_header_end:


I didn't see any resulting video changes tho .... :o ... no surprises there ....


Wed Sep 01, 2010 4:24 pm
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