Search found 116 matches
- Sun Mar 14, 2021 8:10 pm
- Forum: Programming
- Topic: A new data compressor called ZX0
- Replies: 286
- Views: 20867
Re: A new data compressor called ZX0
Am I understanding correctly that the 6502 depacker is not compatible with output from the original compressor?
- Sun Mar 07, 2021 6:46 pm
- Forum: Programming
- Topic: Why can I hear this?
- Replies: 9
- Views: 570
Re: Why can I hear this?
The main reason for the parasite tone here will probably be the fact that this loop is not timing-stable, because of IO contention. Aligning the output to a multiple of 8 t-states should improve the result somewhat, but there will still be whine. di xor a ld bc,0x10fe ld hl,loop loop: xor b ;4 out (...
- Tue Feb 16, 2021 10:38 pm
- Forum: Programming
- Topic: Adding music to a program
- Replies: 19
- Views: 664
Re: Adding music to a program
P.S. It’s not a good idea to concatenate TAP files, because aside from actual data, they contain additional information relevant to the container itself. You’ll end up with a bunch of garbage at the “joint” of the files. Is that really true? The .tap format is pretty much made to facilitate concate...
- Tue Feb 09, 2021 10:23 am
- Forum: Music
- Topic: Sample to BEEP in the olden days
- Replies: 21
- Views: 1556
Re: Sample to BEEP in the olden days
Do you have an example of that? I know [mention]RMartins[/mention] tried a couple of years ago, and it was just barely working (for mixing two channels). It's unfeasible for two reasons, first of all because it takes too much memory, and second of all because the Speccy is barely fast enough for the...
- Mon Feb 08, 2021 11:20 pm
- Forum: Music
- Topic: Sample to BEEP in the olden days
- Replies: 21
- Views: 1556
Re: Sample to BEEP in the olden days
This is interesting: http://www.robeesworld.com/blog/58/pulse-width-modulation-how-1-bit-music-works It shows how a sine wave can be cut up into varying hi/lo cycles at a fixed rate (Pulse Width Modulation). For replay, this relies on the smoothed response of the speaker circuit. Is there a similar...
- Sun Feb 07, 2021 8:34 pm
- Forum: Music
- Topic: Sample to BEEP in the olden days
- Replies: 21
- Views: 1556
Re: Sample to BEEP in the olden days
A third method is open to you if you have other processing hardware. You convert the sound into a very fast stream of dithered bits that rely on the resistor/capacitor circuit of the Speccy's speaker to smooth them out into an audio waveform. Though I've never seen any software that can generate th...
- Tue Jan 19, 2021 4:23 pm
- Forum: Programming
- Topic: A new data compressor called ZX0
- Replies: 286
- Views: 20867
Re: A new data compressor called ZX0
Fantastic work, thanks a lot Einar! Running a few tests shows that ZX0 works very well for my most common use case, compressing data for music players. Very exited to see something that can beat apack.
- Thu Jan 14, 2021 10:46 pm
- Forum: Emulators
- Topic: MAME 0.211 and the Spectrum
- Replies: 21
- Views: 6555
Re: MAME 0.211 and the Spectrum
The checksums for the Speccy ROM files required by MAME have not changed since the MESS merge in 2012, so the ones you have will most likely work just fine.
https://github.com/mamedev/mame/blame/b ... ectrum.cpp
https://github.com/mamedev/mame/blame/b ... ectrum.cpp
- Mon Sep 28, 2020 7:47 pm
- Forum: Programming
- Topic: AMP16K: Multichannel beeper sound on the ZX Spectrum 16K
- Replies: 7
- Views: 1552
Re: AMP16K: Multichannel beeper sound on the ZX Spectrum 16K
Congratulations on reaching this milestone! Excellent work. I think your current data layout would indeed be fine as is, provided you use an order list with it (not just one single long pattern). Any chance for releasing the source code? Preferably under a permissive license (MIT, BSD, WTFPL), would...
- Tue Jul 28, 2020 6:32 pm
- Forum: Showcase your work!
- Topic: ZXAV - An Audio/Visual Sequencer
- Replies: 8
- Views: 5431
Re: ZXAV - An Audio/Visual Sequencer
A big fat thumb up from me, too. Outstanding work.
- Sun Jul 26, 2020 12:43 pm
- Forum: Website
- Topic: Certificate errors on www.spectrumcomputing.co.uk
- Replies: 7
- Views: 942
Re: Certificate errors on www.spectrumcomputing.co.uk
Works for me now
- Sun Jul 26, 2020 10:31 am
- Forum: Website
- Topic: Certificate errors on www.spectrumcomputing.co.uk
- Replies: 7
- Views: 942
Re: Certificate errors on www.spectrumcomputing.co.uk
I can confirm the issue. The cert seems valid for https://spectrumcomputing.co.uk only. Nothing to do with Google, happens when typing www... directly into the address bar. www.spectrumcomputing.co.uk uses an invalid security certificate. The certificate is only valid for spectrumcomputing.co.uk. Er...
- Sat Jul 18, 2020 12:33 am
- Forum: Showcase your work!
- Topic: Learning Assembly Project
- Replies: 5
- Views: 1926
Re: Learning Assembly Project
Ha, that actually looks like you're past the "learning Assembly" stage, and are now headed for the "having fun with Assembly" stage
- Wed Jul 15, 2020 1:22 pm
- Forum: Announcements
- Topic: SC Retro
- Replies: 122
- Views: 33675
Re: SC Retro
Hmm, "micro", that's something I could get behind, too.
Other than that, "lite" is still my one of my favourites (though it basically was rejected already), and of course [mention]Juan F. Ramirez[/mention]' glorious "16K".
Other than that, "lite" is still my one of my favourites (though it basically was rejected already), and of course [mention]Juan F. Ramirez[/mention]' glorious "16K".
- Wed Jul 15, 2020 12:42 am
- Forum: Announcements
- Topic: SC Retro
- Replies: 122
- Views: 33675
Re: SC Retro
We have a winner.
- Sun Jul 12, 2020 10:32 pm
- Forum: Programming
- Topic: (z80 assembler) Disabling break?
- Replies: 3
- Views: 791
Re: (z80 assembler) Disabling break?
In other words, it's disabled by default in assembly
- Sun Jul 12, 2020 3:57 pm
- Forum: Announcements
- Topic: SC Retro
- Replies: 122
- Views: 33675
Re: SC Retro
Media queries are so 2019 flex-grow/flex-shrink is all the hype now.
Another vote for the v3 banner, btw. In fact I'd like it to be even smaller.
Another vote for the v3 banner, btw. In fact I'd like it to be even smaller.
- Sat Jul 11, 2020 12:16 am
- Forum: Announcements
- Topic: SC Retro
- Replies: 122
- Views: 33675
Re: SC Retro
Also +1 to @8BitAG's suggestion. I'm rather allergic to the word "retro". I don't get why you guys don't like word "retro". Personally I have no problem with calling myself and my interests retro, oldschool and vintage ;) And people seem generally to like this words too. Especia...
- Fri Jul 10, 2020 11:52 pm
- Forum: Music
- Topic: Fast AY music players?
- Replies: 18
- Views: 15944
Re: Fast AY music players?
If anyone has need for music for a custom AY player for which no dedicated editor is available, I will be able to support those in Bintracker soon (in a couple of months). So just get in touch if need arises!
- Fri Jul 10, 2020 9:50 pm
- Forum: Announcements
- Topic: SC Retro
- Replies: 122
- Views: 33675
Re: SC Retro
Here's an initial version: https://spectrumcomputing.co.uk/retro/4087 It should work for any game page URL from SC, just replace "entry" with "retro". I know some fields are still missing, don't worry about it, I will take care of these details later. Next step will be adding a ...
- Wed Jul 08, 2020 3:50 pm
- Forum: Programming
- Topic: Issues using zx7
- Replies: 15
- Views: 1833
Re: Issues using zx7
Difficult to say without seeing the code. Perhaps you could post it somewhere so people on here can take a look?
- Wed Jul 08, 2020 3:41 pm
- Forum: ZXDB Discussion
- Topic: New WoS and ZXDB
- Replies: 258
- Views: 58833
Re: New WoS and ZXDB
+1 to what [mention]akeley[/mention] said. As has been demonstrated countless times in the past, Lee and his clique aren't interested in a rational discussion, so arguing with them is a waste of time. Other than that there's no need to defend yourself [mention]Einar Saukas[/mention], you've done mor...
- Mon Jul 06, 2020 11:08 am
- Forum: Programming
- Topic: Help me understand the use of 'AND' here
- Replies: 22
- Views: 2378
Re: Help me understand the use of 'AND' here
It's especially helpful in cases like the one you were struggeling with with "and 31" and "first 8K of ROM". The decimal numbers 31 and 8191 tell you nothing. 0x1f and 0x1fff on the other hand immediately let you see that you don't need to worry about the low byte. Or take PeterJ...
- Sun Jul 05, 2020 3:36 pm
- Forum: Programming
- Topic: Help me understand the use of 'AND' here
- Replies: 22
- Views: 2378
Re: Help me understand the use of 'AND' here
"8K" = 8192 bytes. So the first "8K of ROM" means an address between 0 and 8191. 8191 = %11111 11111111, or 0x1fff. We don't need to worry about the lower 8 bits, since they may take any value. The upper 8 bits on the other hand must have a value between 0 - %11111, or 0 - 0x1f, ...
- Sun Jul 05, 2020 3:20 pm
- Forum: Programming
- Topic: Help me understand the use of 'AND' here
- Replies: 22
- Views: 2378
Re: Help me understand the use of 'AND' here
a) does this have bias on larger numbers (ie. if a>=31; AND 31 would always equal 31 ???)? No. A logical AND operates on individual bits. The result of ANDing two bits is 1 if and only if both of the pair of bits are 1. %00110001 (= 49 decimal) AND %00000111 (= 7 decimal) ========================= ...