Z80 Size Programming Challenge #4

The fourth Z80 challenge for the ZX Spectrum was issued last week:

Back to something simple for the next challenge, a diagonal fade-to-white CLS. Write the shortest code to wipe the screen by increasing the ink colour of each character until it reaches white.

The clear should start at the top left and move one character across the screen per frame. The initial screen can be assumed to be monochrome — black text, white background, flash off, bright off. There’s no need to clear the screen bitmap. Here’s a demonstration of the clear in slow motion:

Target: under 50 bytes.

The deadline is Monday 6th April, midday (GMT).

  1. Your program shouldn’t rely on the initial contents of registers.
  2. Programs must halt between frames. The HALT is included in the size.
  3. No RAM/ROM other than the attribute memory should be written to.
  4. Programs must return. The RET instruction is included in the size.
  5. So everyone has a fair chance comment with the code size not code.
  6. There are no prizes, just the chance to show off your coding skills.

read more…

thanks to JM @ http://www.retroprogramming.com/

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