Ask HN: What bug(s) make “LPRINT 0.00001” output “0.0XYZ1”?

2 points

7 years ago

https://en.wikipedia.org/wiki/Timex_Sinclair_1000#Bugs states:

  On the TS1000 and ZX81, the command:

    LPRINT 0.00001

  results in the Timex printer outputting 0.0XYZ1.

I find that a curious bug (my best guess is that the “XYZ1” part is uninitialized memory, but even if that’s true, why would 0.00001 be special?), so I tried to track it down. to my surprise, I found very little. The best I found is https://www.tablix.org/~avian/spectrum/rom/zx81.htm, but that’s incomplete, and of the “Improved” ROM, which, presumably, doesn’t have that bug.

So, does anybody know how that bug came to be?

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