Z80 Size Programming Challenge #3

Recently I issued the third Z80 programming challenge for the ZX Spectrum:

This time the challenge is to write the shortest code to display a masked 16×16 pixel sprite. The routine should be called with the address of the sprite data in one register and the X and Y screen coordinates in another. There’s no need to save the screen area being overwritten or set the colours / attributes. This is somewhat trickier than previous challenges but more likely to be of practical use.

The deadline is Monday 30th March, midday (GMT).

Target: under 125 bytes.

1. The X and Y coordinates are in pixels with 0,0 at the top left.
2. The sprite needs to be clipped if it goes over the screen edge.
3. Sprite data can be formatted however you like within 64 bytes.
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.

Solutions can be emailed to digital.wilderness@googlemail.com or posted here after the deadline.

 

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