Specifications
------------.---------------------------_._._-------.-----------
Softwa~
for the
Video
Display Interface
------------------------------------
.----------------------_._------.-----------
The
uti l
ity
routine
CHRLD.cOM,
suppl ied
on
the
distribution
diskettes,
is
used
to
load
a
character
set
for
either
the alphanumeric or graphic display drivers
which
are part of the
QUARK
operating system.
In case of alphanumeric terminal emulation,
CHRLD.cOM
is
used
to
load
a character set into
the
Programmable
Character Generator.
In
case of graphics terminal emulation, the
program
is
used
to load a character set into the
RAM.
This
utility
can
be
used
to
load
either
the default
character set
imbedded
within the
CHRLD.COM
file,
or
any
other character set
saved
in a
file
on
a diskette.
The
character set
used
for alphanumeric display
is
a
full
256-character
set,
including
both
normal-
and
reverse-video characters for the
QUARK.
The
character set
is
intended
to
be
used
with
ASCII
codes.
Each
character is stored
as
eight contiguous bytes within the data
file.
For
further information
on
the operation of the
Programmable
Character Generator or the
Video
Display Interface, refer to the
Hardware
section of
this
manual.
----._-------------------------------------------.
__
._----------------------------------------
CHRLD.COM
-
The
Character Generator
Loader
for
CP/M
Plus
This fi le
wi
II
load
the default character
set,
the data for
which
is
contained within
CHRLD.cOM
itself.
If
the user wishes to
load
the default character set
after
the system
is
up,
it
is
necessary only to enter the following
command:
A>CHRLD
A>
To
load
another character set into either the
Programmable
Character Generator or
RAM
without
altering
the
CHRLD.COM
fi
le, specify the character set
fi
le
name
on
the
command
line
immediately following the
command
CHRLD.
CHRLD
will find the character set
file
and
load
the
specified character set
file.
The
following is
an
example
of
this
use
of
CHRLD.COM:
A>CHRLD
CHR.DAT
A>
The
character set
"CHR.DAT"
set
wi
II
remain
unti l another character set
is
loaded, or
until
power
is
removed.
Character set
files
can
be
created or modified using the Character Set
Editor
CHRED.COM.
To
change
the default character set within
CHRLD.COM
a desi red character set fi le
must
be
patched into
CHRLD.COM.
To
perform
this
patch,
load
CHRLD.COM
at address
0100H,
and
load
the
fi
l~
containing the
new
character set to address
103h.
Make
sure the
new
data
set
is
not
greater than
8K.
An
example
is
presented
below.
A>DDT4
CHRLDJ:OM
#ICHR.DAT
#R103
#60
A
>SAVE
13
TCHRLDJ:OM
Megatel
Computer
Technologies
CP/M
2.23 Software Section
Page
S/W-
28