archive.worldofdragon.org

Performed recovery on this and retyped the mangled lines. This is a pretty cool Pac Man style game using fun video modes, as discussed here (and indeed, I used these scans to fix):

viewtopic.php?f=4&t=44

BTW, "recovery" here means patching the BASIC ROM to ignore IO errors (ie, load as much as possible), doing a CSAVE"",A to get a blocked ASCII file, removing the block headers and checksum bytes (simple search & replace in vi) and then manually looking over it to see what's broken. I had three copies on the one tape, which helped (none were perfect, but in most cases, different areas were mangled).

Line 9080 has a checksum for the long DATA lines. Ah, nice memories on how we learnt some of the tricks of the trade.

Here is an improved version of the game.

+ Fixes a bug that was carried over from the original game.
+ Much quicker when poking in the machine code data at the "MACHINE CODE ASSEMBLING" stage.
+ Slightly quicker when building each new maze.
+ Improved keyboard response on Dragon 32/64 type machines.
+ Arrow keys used as control keys.
+ Player selectable use of the double speed poke.
+ Uses X=RND(-TIMER) to randomize the RND() function.
+ Error messages.
+ Added support for Tandy CoCo machines.
+ Single source code for both CoCo and Dragon machines.


This version of the game is known to be compatible with the following machines:

Dragon 32
Dragon 64
Dragon 64 by Tano
Dragon 200
Tandy CoCo 1 and 2 (Requires 32K of RAM and Extended Color BASIC)

It may also be compatible with the following machines:

Dragon Professional (Alpha)
Prologica CP-400 (Requires the 64K RAM version)
LZ Color 64
Dynacom MX-1600

It is not compatible with the following machines:

Dragon 200 - E
Tandy CoCo 2B (The 6847T1 VDG version)
Tandy CoCo 3

List of error messages returned by this version of the game:

IC ERROR (Incompatible Computer Error). This error is returned if you try to run the game on a computer that is known not to support the SG6 graphics mode (Excluding the CoCo 2B).

IB ERROR (Incompatible BASIC Error). This error is returned if you try to run the game on a CoCo 1/2 that does not have Extended Color BASIC.

IM ERROR (Incompatible Memory Error). This error is returned if you try to run the game on a 16K CoCo 1/2 after entering PCLEAR1 or POKE26,6:NEW before loading from cassette. The same error will be returned if you try to run the game on a Dragon 64 in "64 Mode". It will also be returned if any type of DOS is active.

Both Dragon and CoCo compatible versions are included.

Does this work fine on real CoCos then? I thought there might be an issue with the data bus being latched before the VDG in a way that differs to the Dragon.

I don't have a CoCo 1/2 with an original VDG (it's definitely going to look no good on a T1), so never actually been able to test that mode.

sixxie wrote:Does this work fine on real CoCos then? I thought there might be an issue with the data bus being latched before the VDG in a way that differs to the Dragon.

I'm not sure. My information is based on the following assumptions.

(A) I know that the CoCo 1 and 2 display other semigraphic modes correctly.
(B) If the game didn't display correctly on a real CoCo, the same problem would be properly emulated by XROAR and MESS.


I ran them both side-by-side under XROAR CoCo and Dragon emulation, and they appear to be identical. Perhaps someone will be kind enough to test the game on their real CoCo, and let us know the result.

You will need Steve Woolham's DOS detach utility if you want to run the game after loading from DOS floppy disk.

sixxie wrote:Does this work fine on real CoCos then? I thought there might be an issue with the data bus being latched before the VDG in a way that differs to the Dragon.

I have now tested the CoCo version of the game on one of my real CoCo 1 machines. The display on all six screens (demo mode) was side-by-side identical to the emulated Dragon version.

This game should work perfectly on any real CoCo 1/2 (Excluding CoCo 2B).

You can easily check if your CoCo 2 is the B model by entering POKE359,57:POKE65314,PEEK(65314)OR16 and pressing Shift+0 to enable lower case. The B model will actually display true lower case letters instead of inverse text.

zephyr wrote: I have now tested the CoCo version of the game on one of my real CoCo 1 machines. The display on all six screens (demo mode) was side-by-side identical to the emulated Dragon version.

Excellent - good to know! I guess the stuff I read in passing about the CoCo differing there must have been about the "2B" with the 6847T1.

Here is a further improved version of the game. This special version of the game will enable 6309 "native mode" if it detects that your CoCo or Dragon is fitted with a Hitachi 6309E processor. When switched into 6309 Native Mode (as opposed to the default 6809-compatible mode) many key instructions will complete in fewer clock cycles. This helps to improve the overall execution speed of the game.

I have also cleaned-up/optimized the BASIC code slightly.