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Confused?
The HOB bit is used only to read back the full 48-bit LBA. The
HOB bit is not used when writing the LBA to the device. In fact
the HOB bit is set to 0 by the device on any write to a Command
Block register.
So lets assume you are running on a stupid x86 with little endian
byte ordering and you have the 48-bit LBA in some memory area
(most likely stored in a 64-bit data area) like this:
addr LBA
offset bits
------ ----
0 7-0
1 15-8
2 23-16
3 31-24
4 39-32
5 47-40
6 not used
7 not used
I assume the algorithm would look like this:
if ( 48-bit_command )
{
write offset 3 to Sector Number (LBA 31-24);
write offset 4 to Cylinder Low (LBA 39-32);
write offset 5 to Cylinder High (LBA 47-40);
}
write offset 0 to Sector Number (LBA 7-0);
write offset 1 to Cylinder Low (LBA 15-8);
write offset 2 to Cylinder High (LBA 23-16);
if ( 28-bit_command )
{
write 40H (LBA=1) OR'ed with bits 3-0 of offset 3
to Drive/Head (LBA 27-24);
}
Did I get it right?
*** Hale Landis *** [EMAIL PROTECTED] ***
*** Niwot, CO USA *** www.ata-atapi.com ***
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