Title: Tandy Assembly Demo
Author: Simon Jonassen
Publisher: Simon Jonassen (2017)
Platform: Tandy TRS-80 Color Computer

Transfered to cassette and cartridge by Steve Evans (Zephyr) on the 14th of January, 2025.

Modified to allow a customised on-screen time by Steve Evans (Zephyr) on the 16th of January, 2025.

Uploaded to the Dragon Archive Forums by Steve Evans (Zephyr) on the 16th of January, 2025.
https://archive.worldofdragon.org


Two cartridge versions (ASMDEMO and ASMDEMO2) are included:

The ASMDEMO cartridge returns control to the BASIC operating system. To start the demo, enter EXEC at the command prompt.

The ASMDEMO2 cartridge automatically runs the demo in a continuous loop. This version is ideal for leaving the demo on display at computer shows, etc.


Both cassette and cartridge versions will also run on a Dragon 32 or a Dragon 64 (in 32K mode).


This is a slightly modified version of my original release that I uploaded to the Dragon Archive Forums on the 15th of January, 2025.

Both the cassette and cartridge versions now have the demo speed regulated by a 16 bit delay routine driven by the 50/60Hz IRQ which simply wastes CPU time to regulate the amount of time that the demo stays on screen for. The 16 bit value that determines the amount of delay time is stored at memory locations $7F00:7F01 of the cassette version. The default value of #$1400 gives a on-screen display time (on my emulated Dragon 32) of 1:53 for all of the animated parts of the demo. This is pretty close to the 1:47 on-screen time noted from watching Simon's YouTube video of the original demo running on a emulated CoCo.

You can customise the delay time by loading the cassette version and poking in your own values to give you the on screen time that you prefer. Once you are satisfied with the amount of time that the demo is on screen for, you can save the modified version back to cassette with CSAVEM"ASMDEMO",&H5C00,&H7F01,&H7EE3 along with your prefered 16 bit delay value.

When you are happy with your custom 16 bit delay value, you can then cusomise the cartridge versions with a hex editor. The memory locations are $233A:233B for ASMDEMO.ROM and $2319:231A for ASMDEMO2.ROM.


Steve Evans (Zephyr)
https://archive.worldofdragon.org


