Search found 320 matches

by Seven.FFF
Thu Jul 18, 2019 7:27 pm
Forum: Programming
Topic: BEEP VAL
Replies: 36
Views: 568

Re: BEEP VAL

My theory is that the ZXs should appeal to hackers. And to gamers, i.e hackers who do games. So hackers it is. They like things which are transparent, pushed to the limit and extendable. That may be what we'd all like to be true, but the reality is different. Many of the decisions they made make it...
by Seven.FFF
Thu Jul 18, 2019 7:24 pm
Forum: Programming
Topic: BEEP VAL
Replies: 36
Views: 568

Re: BEEP VAL

"Tape loading? We could use it to listen to the tape. Oh, and we could use it to read the keyboard too." Expanding on my earlier observation that the ULA beeper circuit is the same circuit that outputs the tape MIC signal... it's almost certainly similar to the ZX81 tape circuit too. It's not like ...
by Seven.FFF
Tue Jul 16, 2019 4:47 pm
Forum: Programming
Topic: BEEP VAL
Replies: 36
Views: 568

Re: BEEP VAL

In his (highly recommended) ULA reverse-engineering book, Chris Smith documents that the sound generation shares the same circuit as the tape output, and surmises it was done that way for efficiency (needing less logic gates in the ULA, which means more room to fit other functionality in).
by Seven.FFF
Tue Jul 09, 2019 3:25 pm
Forum: Graphics
Topic: Why is a simple B&W line drawing 4 megs?
Replies: 5
Views: 198

Re: Why is a simple B&W line drawing 4 megs?

Another thing you could probably say, is that pencil is not a great choice for precise drawings. It's great at conveying subtle shading in looser art forms, and some architects can make it work for them by adopting a style that's both precise and loose (by emphasising points and line ends, while rel...
by Seven.FFF
Tue Jul 09, 2019 3:15 pm
Forum: Graphics
Topic: Why is a simple B&W line drawing 4 megs?
Replies: 5
Views: 198

Re: Why is a simple B&W line drawing 4 megs?

1) You have a lot of pixels - 3049 x 2086 is nearly 6 and a half million, and data for each one has to be stored separately, albeit in a compressed/simplified form. 2) It's not a black and white image, you have a lot of very similar shades of grey, with each pixel next to another pixel of a differen...
by Seven.FFF
Tue Jun 25, 2019 5:08 pm
Forum: Hardware
Topic: Easy way to put games on real tapes
Replies: 8
Views: 284

Re: Easy way to put games on real tapes

The Zeus dev emulator has controls to emulate variable speed error, wow and flutter, and some other tools to assist with writing custom loaders or turbo loaders.

They can be useful to determine the tolerance of any custom code or mastering you might do.
by Seven.FFF
Sun Jun 23, 2019 6:28 pm
Forum: Hardware
Topic: ZX Spectrum Next Discussion
Replies: 187
Views: 9657

Re: ZX Spectrum Next Discussion

The board has a 2-tail connector socket. The hand-soldering is just awkward wording. It refers to the socket being fitted at SMS by hand in rework stations, as the assembly line board manufacture has already happened a long time ago.
by Seven.FFF
Fri Jun 21, 2019 6:41 pm
Forum: Programming
Topic: Zeus assembler - code generation?
Replies: 16
Views: 877

Re: Zeus assembler - code generation?

And yes, the original Z80 instructions have to be 100% timing critical, as does the other virtual hardware like ULA, divMMC, multiface, etc. People are wanting these machines precisely because there are an exact number of Ts per line and lines per frame, with known instruction timings, for all the m...
by Seven.FFF
Fri Jun 21, 2019 6:28 pm
Forum: Programming
Topic: Zeus assembler - code generation?
Replies: 16
Views: 877

Re: Zeus assembler - code generation?

You do, because backwards compatibility with earlier Next cores is being strictly maintained. The early games that were published well over a year ago still work, no breaking changes are deliberately made, and every core build is tested quite rigorously against existing software to guard against acc...