** This is the quasi-official and semi-temporary T13 email list server. **
Okay but was it not the job of the HOB to sequence the loading of the
registers or is that just for reading?
Andre Hedrick
Linux ATA Development
On Thu, 24 May 2001, Hale Landis wrote:
> Date: Thu, 24 May 2001 10:47:59 -0600
> From: Hale Landis <[EMAIL PROTECTED]>
> Reply-To: [EMAIL PROTECTED]
> To: "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
> Subject: [temp t13] Re: 48-bit LBA
>
> ** This is the quasi-official and semi-temporary T13 email list server. **
>
> DID I GET IT RIGHT? Answer: NOT QUITE. Here is updated algorithm...
>
> 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
>
> The updated/corrected algorithm would look like this (and
> I added Sector Count too):
>
> if ( 48-bit_command )
> {
> write bits 15-8 of sector count to Sector Count;
> 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 40H (LBA=1) OR'ed with DEV to Drive/Head;
> }
> write bits 7-0 of sector count to Sector Count;
> 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 DEV
> OR'ed with bits 3-0 of offset 3
> to Drive/Head (LBA 27-24);
> }
>
> I think this is "more correct"?
>
>
> *** Hale Landis *** [EMAIL PROTECTED] ***
> *** Niwot, CO USA *** www.ata-atapi.com ***
>
>
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