MACHINE CODE SUBROUTINE TO GET COORDINATES
EXAMPLE 3 – MBASIC
This Basic program, which is well sprinkled with REM statements, is provided as a
guide that others can follow. As it is purely for demonstration purposes the
program has been coded for clarity.
Note: In line 1020 ADDR holds the address of where the USR routine is stored.
Nascom Basic/Nas-Sys users should pick an area within the workspace RAM
(0C80H-0FFFH). GM809 users on a Nascom can use the workspace RAM as well, though in
their case it is located at 0FC00H-0FFFFH. (NB Your CP/M system size should be 63K
or less if you intend to use the workspace RAM).
For Multiboard users the problem is slightly more complex. Either a CP/M system can
be used that is 1K less than the available memory size, or the /M option can be
used when loading MBASIC to leave an area of RAM free for the machine code program.