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* The MBR boot code did execute the check for disk extensions with the wrong

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magic code. This would lead to them not being detected on systems where the
  BIOS (rightfully) returns an error in this case. Since the CHS fallback can't
  work it would then fail with "Missing Operating System".
* Fixed a typo, an 80 char limit violation.
* Automatic whitespace cleanup.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35718 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Michael Lotz 2010-03-02 01:28:49 +00:00
parent aceebab740
commit 1487898473
1 changed files with 6 additions and 6 deletions
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12
src/bin/writembr/mbr.S
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@ -37,7 +37,7 @@ start: cld // String ops inc
/*
* Relocate ourself to a lower address so that we are out of the way when
* we load in the bootstrap from the partition to boot.
*/
*/
movw $main-EXEC+LOAD, %si // Source
movw $main, %di // Destination
movw $0x200-(main-start), %cx // Byte count
@ -94,7 +94,7 @@ main.5: movw %sp, %di // Save stack pointer
jnz main.7 // No.
pushw %cx // Save %cx
pushw %bx // Save %bx
movw $MAGIC, %bx // Magic
movw $0x55aa, %bx // Reversed Magic
movb $0x41, %ah // BIOS: EDD extensions present?
int $0x13 //
jc main.6 // No.
@ -109,7 +109,7 @@ main.5: movw %sp, %di // Save stack pointer
pushw %bx // the transfer buffer
pushw $0x1 // Read 1 sector
pushw $0x10 // Packet length
movw %sp, %si // Packer pointer
movw %sp, %si // Packet pointer
movw $0x4200, %ax // BIOS: LBA Read from disk
jmp main.8 // Skip the CHS setup
main.6: popw %bx // Restore %bx
@ -119,8 +119,8 @@ main.8: int $0x13 // Call the BIOS
movw %di,%sp // Restore stack
jc err_loading_os // If error
/*
* Now that we've loaded the bootstrap, check for the magic 0xaa55 signature. If it
* is present, execute the bootstrap we just loaded.
* Now that we've loaded the bootstrap, check for the magic 0xaa55 signature.
* If it is present, execute the bootstrap we just loaded.
*/
cmpw $MAGIC, 0x1fe(%bx) // Bootable?
jne err_missing_os // No
@ -141,7 +141,7 @@ err_missing_os:
jmp putString //
/*
* Output an ASCIZ string to the console via the BIOS.
*/
*/
putString.0:
movw $0x7, %bx // Page:attribute
movb $0xe, %ah // BIOS: Display character