Radio Shack TRS-80 Owner's Manual page 100

1
—
in,
IS-80
MODEL
Id
DISK
SYSTEM
$DMULT
—
17486/X»444E'
The
multiply routine uses
a 16-bit multiplicand and an
eight-bit multiplier. After
multiplication takes place, the product
replaces
the
16-bit
multiplicand.
Entry Conditions
hl
=
Multiplicand
a
=
Multiplier
CALL
SDMULT
Exit Conditions
H
=
High
order byte
L
=
Middle order byte
a
= Low
order byte
H
L
A
High Middle
Low
$RAMDIM^
17040/X'4290'
This routine allows
you
to
examine
a diskette directory (one entry or
the entire
directory) or the diskette's free
space.
The
information
is
written into a user
specified
ram
buffer.
Only non-system
files
will
be included
in the
ram
directory.
Entry
Conditions
hl
=
ram
Buffer.
If
c
=
0, size
=
1761
[max
#*22+
1].
If
c
=
i
to 96,
size
=
22.
If
c
=
255,
size
=
64.
b
=
Specified drive
number
c
=
Function
switch:
Contents of
C
1-96
255
CALL SRAMDIR
Results
Gets
entire directory
into
ram.
(See
ram
Directory Format).
Gets one
specified directory record
into
ram,
if
it
exists.
(See
ram
Directory Format).
Gets
free-space information
(See
ram
Directory Format).
Exit Conditions
nz
=
Error occurred.
z
= No
error. (HL)
=
directory or free-space information.
84