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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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