[no subject]

The 10-bit values are basically 8-bit $FF bytes with 2 "0" bits preceeding
them.
These 10-bit values exploit a hardware limitation in the proms on a
16-sector
disk][ controller card to synchronise the disk read hardware to the start of
each
byte in the disk data stream.
It is explained reasonably well in the "beneath" manuals.

> Is it possible to add "STA
> 4000" between LDA and BPL so I can see one bit out of 8 bits into one byte
> storage?

Each byte from the disk data streams through the read register every 32
clock
cycles, which indicates that the high bit of the read register will hold a
new value
(although it may not change state) every 4 clock cyles.
If you dissassemble the the sector read code you will find that each byte is
read at exactly 32 clock cycle intervals.

There simply isn't enough time for extra instructions in the disk read loop
when
you are running on a stock 1MHz Apple2.

>  Why do EOR #D5 have to be used instead of CMP like AA and 96.

No particular reason that I can see.

>     I do have Beneath Apple DOS/ProDOS manual in front of me, but it does
> not provide me enough information.  It is why I am asking a question in
> newsgroups so someone might be able to provide more information.  I
> appreciate this.
>
>
>
> --
> Yours Truly,
>
> Bryan Parkoff
> BParkoff@satx.rr.com
>
>

Cheers,
Red