Sinclair ZX80 / ZX81 / Z88 Forums

You're welcome! My first computer was a ZX80, for Christmas 1980 (when I was 12). 1K. Strangely, with an inverted display! Second hand! I sold it for £40 in mid 1981 as part of the trade-off for getting a ZX81. There's an austere beauty about the ZX80 & it's surprising what you can get it to do - pr...

It's possible to write a variant of MiniMorse for the 1K ZX80. We need to do this in two parts. Strings can't be indexed on a ZX80; we can't type all the printable characters (can't type inverse characters); and some characters are remapped if you type them (e.g. PRINT CHR$(18), CODE("-") displays '...

Thanks! Good insights here too! I hadn't really considered using LEN A$ in place of A$<>"" (2bytes) or NOT LEN A$ (saving 1b). I'd use GOTO PI and the FOR F ... PI*PI, but probably not the EXP PI and PI**PI as they might slow the program more than I'd want. For some applications though it'd be a bet...

Excellent! Here's a version that's only a mere 405 bytes long of actual code, with just 32b of variables. Using I to represent 1 doesn't yet save as much space as repeatedly using SGN PI does; similarly, B=I+I is slightly longer than using CODE "[Graphic+Shift+2]". I've replaced all the remaining nu...

Ha! Yes, that's a really good point! I did use an indexed literal string in part of the program, but it didn't occur to me to use it for the actual translation strings. I could have saved quite a number of other bytes in the code by using CODE "x", VAL "x", NOT PI, SGN PI, kind of thing. Mostly I wa...

This is always the kind of Morse Tutor I would have wanted to use, even though it doesn't care about the relative lengths of the dots and dashes. That's because I want a low-barrier to entry and I don't want it to be too guided, with me having to progress from Level 1 to whatever they've prescribed....

Our family plays Monopoly every Boxing Day and the winner gets to keep our Monopoly trophy for a year with their name inscribed on a new lolly stick. Since I've never won, I wanted to simulate the game of monopoly to find out if I could improve my chances :-) . Naturally, it's not good enough just t...

For fun I wanted to reproduce the Jupiter Ace sine wave program on a ZX80 in BASIC. ZX80 Basic of course doesn't provide PLOT or UNPLOT, the display is inconveniently after the workspace and variables (so you can't just cache the start address) and the block graphics character codes are in a wacky o...