Date   : Wed, 23 Nov 1983 02:05:00 EST
From   : David Sternlight <STERNLIGHT%USC-ECL@sri-nic>
Subject: SD bug

There is a bug in sd-77 which has been around for a while.  When SD
goes to look at the S2 byte of the file control block to see if there
are more extents than 3, it looks at the whole byte.  This is
inconsistent with CP/M practice, which uses the lower 4 bits only of
this byte.  (Never mind what David Cortesi says in his book; he is
mistaken.)  Thus an ani 0fh needs to be inserted in the code to mask
out the relevant bits.  Otherwise, programs such as qbax, which use
the higher bits for such things as archive flags will (if they set a
file as backed-up) cause sd to report the file size as 256k too large.
The place for the ani 0fh is just following the (second) LDAX D after
TMOVE:, which loads the s2 byte.
--david--