Re: Asteroids Problem Solved..

>Tom, let me know what you come up with because I'd like to use those same
>commands for my test roms. That way those of us without a catbox can still
>make use of them.

To really test the vector ROMs you should do a couple things (probably in
sequence stepped by a button or something):

1) Short direct drawing commands (<8 bytes total), draw a plus or something
(the "are you alive?" test)
2) short drawing sequence, but draw a box at the current beam location
(that'll test a little more of the VSM program counter)
3) Make the box a subroutine, then JSR to it. (Test one level of stack)
4) Make a "/" the size of the box. Have the "/" call the box as a
subroutine. Call the "/" from the display list (tests two levels of stack).
5) Make a "\" the size of the box. Have the "\" call the "/" (which calls
the box). Call the "\" from the display list (test three levels of stack.
6) Now make a longer sequence that draws a the "X" box in each quadrant of
the screen. (tests more of the program counter)
7) Locate the draw sequence (terminated by a VGHALT) every 128 bytes or so
in VRAM. JMP to it from the beginning of VRAM. With every button press,
increment the JMP to the next sequence in VRAM. That'll test the rest of
the program counter across VRAM (and the VRAM itself to a certain degree).

Then you'll need to display objects from the game ROMs to make sure you can
see all of those OK. (The rest of the Program counter range basically)

It'd be neat to do a real CRC 16 on the ROMs too-- be a little more thorough
than a checksum. Run a few scale/intensity checks and I'd say the VSM would
be 100% functional if it can do all that. If not, the sequence of tests
should lead you right to the problem. (Bad program counter, bad VRAM area,
bad VSM stack, etc.)

-Clay
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Received on Wed Nov 1 13:23:06 2000