GSX-86: Graphics
for
the
APe
9-46
Sufficient stack space must be available for GSX-86 operations. This includes a
buffer
area
for
points
passed
to
GSX-86
and
some fixed overhead space.
To
determine the
amount
of
stack space required
to
run
a given application, make the
following calculation:
OPEN
WORKSTATION
call = approximately 400 bytes
All
other
calls = ptsin size + 64
where
ptsin is the
point
array
passed to the device driver from the
application
program
(two words
per
point)
The
stack
requirement
is the largest
of
the two resulting values. This stack space
must be available in the application program.
After coding
and
assembling
or
compiling the source code, link it with any required
external subroutines
and
run-time
support
libraries to
produce
a
load
module.
Then,
use the
RENAME
(REN)
command
to
rename the
CMD
file to a file with the
SYS extention.
To
make the driver
known
to GSX-86, include its name in the
Assignment Table
and
associate it with a device.
Graphics
programs
can be debugged like
any
other
application using
DDT-86
or
another
debugger. The default device driver
and
GDOS
are loaded directly above
CPM-86
after
the
GRAPHICS
command
has been executed. The applications
program
is
loaded in the normal
manner,
starting
at
the
top
of
the user area.
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