THE PRINTER. They can then do a ZX81/TS1000/TS1500 combination with the same printer. It would sell stateside.

The Acorn BBC Computer has a very respectable speed and accuracy rating. The ZX Spectrum and Timex machines are not bad for accuracy considering the maths is based on fuzzy logic. It is good to see David Ahl is still going. He put all his work in the public domain.
www.swapmeetdave.com/Ahl/DHA.htm

I go for precision at every turn. I have just made the ZX81 as accurate as the IBM PC. Imagine that back in 1981. Sinclair lost out because of deadlines and a fixation with forward compatibility. For a few bytes more or respite to find the space required. The math pack was frozen for the ZX Spectrum

On the ZX Spectrum Looking Glass ROM I had more room and after removing the red Z80 lines I added an iteration counter in K-DATA 23565. Many roots only require 1 try while most take 5 loops for a perfect solution.
The accompanying BASIC program shows the binary roots and loop counter.

I wrote that routine over 20 years ago on the sg81.rom which is preserved on wayback. The routines that use sqr - asn,acs use mem-0 to mem-2 for several Chebyshev series generations as does the original sqr function which uses to_power,ln and exp. The original ZX81 sqr uses mem-3 indirectly (exp).

The video is quite dramatic for such a short ZX Spectrum program. Wait for it. Watch the lower left hand corner.

40 years ago I had this ZX Spectrum BASIC type-in published in Popular Computing Weekly. The magazine used my Alphacom 32 thermal printout which stands out with a bold font.

An interesting Letters page with two interesting letters about the Spectrum. The first on the inviting space at the end of the ZX Spectrum ROM. The other by Andrew Pennell refers to the 09/09/1982 magazine by Dr. Ian Logan which detailed bugs and Andrew lists a load of bugs in the Vickers manual.

In both the ZX81 and ZX Spectrum the division routine misses a shift and the 34th bit is lost.
As Dr. Frank O’Hara explained a jump to DIV-34TH must be made and not to DIV-START. After division the mantissa is not normalised. Normalisation pulls in the 33rd unset bit from A and bit 34 moves to 33.

The ZX Spectrum BASIC on a single page but don’t type it in. You can download it from Spectrum Computing.

spectrumcomputing.co.uk/entry/17727/...

Here is the Z80 source code from my ZX Spectrum ZEUS assembler.

And on Page 44, yours truly with a short ZX Spectrum type-in “Spherical Objects”. No image or Z80 source code but that is fixed now.

Download The Looking Glass ZX Spectrum ROM V1.08 from

spectrumcomputing.co.uk/entry/44586/...

speccy4ever.speccy.org/_CMS.htm

ZX Spectrum ROMs and games.

A nice Page 179 on BIN, ATTR and pure colours.
Amstrad messed up that text in all their manuals but 30 years later in 2014 Steve’s penguin had the last word on BIN 010 (It’s 2 not 4).

It’s all happening in 1982. Dr. Ian Logan reveals three ZX Spectrum bugs on the letters page and on Page 19 there is a competition to win a newly launched Jupiter Ace.

Download The Looking Glass ZX Spectrum ROM V1.08 from

spectrumcomputing.co.uk/entry/44586/...

speccy4ever.speccy.org/_CMS.htm

ZX Spectrum ROMs and games.

I have seen a YouTube video of Federico Faggin referring to the processor inside as the “Zee-Eighty”. He cleverly designed it so no objections there.

If, as I expect, those ZX Spectrum machines have sold out then you can go to Amazon Prime,
smythstoys.com , Argos etc. and have a much more exciting model for £89.99 😊. With my LG18 v1.08 ROM installed it will run all 48K software. You can get it all on one SD Card too.