Radio Shack TRS-80 model III Owner's Manual page 87

TRS-80
MODEL
III
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 $DMULT
Exit Conditions
h
=
High
order byte
l
=
Middle
order byte
a
= Low
order byte
H
L
A
High Middle
Low
$RAMDIR—
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 $RAMDIR
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.
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