[yyyfb]

"Racing the beam" — omg I know exactly what you mean. We used to set the beam to different color at the beginning and the end of our vsync'd routine to figure out how many scan lines worth of CPU time per frame we could afford to use. I remember the address $dff180 for this purpose (color palette 0, which would always show on the edges of the screen outside of the bitmapped area). We didn't have the Internet to teach us that trick either, all word of mouth! Didn't know there were people still trying to squeeze more out of that chipset nowadays.

[dansalvato]

I use the same trick today! I have some "benchmark" macros set up which forcibly override the background color when I want to see where in the frame my operations are taking place.

> Didn't know there were people still trying to squeeze more out of that chipset nowadays.

You will be amazed. The demoscene has gotten insanely good since around 2017. Here are some of my favorites that all run on a stock Amiga 500 (with the trapdoor memory):

https://www.youtube.com/watch?v=2jciCr8zEhw

https://www.youtube.com/watch?v=iD9xk3SDSYc

https://www.youtube.com/watch?v=pYtleuGV7ok

https://www.youtube.com/watch?v=E0OzX7plbeY

https://www.youtube.com/watch?v=rIV4AhfugIs

[yyyfb]

Wow... Looking at the links on one of these, I see that the tooling has evolved a lot from the days of just text editing + assembly https://tbl.nu/2019/08/20/Tooling/

[sillywalk]

Wow. Thanks for posting these. Reminds me of 8080MPH / Area 5150.

I don't know enough about amiga chipset limitations to know which bits I should be impressed more by, but a doing this on a 68k @ 7mhz with 1MB RAM is impressive enough.