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Applications / Re: Arkos Tracker 2 - Released!
« Last post by manossg on Today at 11:03 »
I am loving using this tracker, congratulations to Targhan!

I have some questions:
1) There are some nice hard basses sounds included in the software and I would like to use these, but these don't seem to be affected by the various effects, including volume commands. Am I doing something wrong?
2) Are there any instrument packs available with more AY goodness? I am trying to create my own, but I end up with messy/scratchy sounds instead and only rarely something barely usable.
Programming / Re: Using Index registers
« Last post by Axelay on Today at 09:08 »

I don't think you can really put in place 'rules' about when you should or shouldn't use them.  They are slow, so when speed is important, it is worth thinking about whether an alternative approach might be faster, but you also need to bear in mind that sometimes the alternatives might end up even slower if too much work is involved in avoiding the index registers and that will be different in each circumstance.

If speed is not important then use them as much as you like, just as roudoudou suggests.  But if speed is important, I think it's worth thinking about how not to use the index registers from the outset, I wouldn't leave it until later myself, at least for the circumstances I might use them.

Some examples of when I do use them:
 - manipulating high score or other tables outside of a game loop when size, structure and speed is of no real concern
 - returning from routines jumped to during stack manipulation using jp (iy) or jp (ix) because call is not available
 - occasionally as a register when no alternative would be an option, or slower in that specific case.  For example, using alternate registers if the firmware is not active

For data structures in game loops, I avoid using the index registers by page aligning the data structures, thinking about what would be accessed most often together and sometimes 'interleave' parts of the data structures together so data can be processed using hl as a pointer with a minimum of 8 bit inc/dec and the occasional set/res.  This does mean the tables I use are a power of 2 in size, with occasional unused bytes, though rarely.  So when it comes to data structures, I don't think leaving optimisation until later is a good idea, as trying to not use the index registers will most likely require re-organising the data structure, and an awful lot of re-coding.
Programming / Locomotive BASIC - Hey Jude
« Last post by ComSoft6128 on Today at 08:12 »
Amstrad Action type-in from June 1992 by Paul Roberts.
Program is Listed at end of video.

From AA:
"Here's 5K of compact code that's going all the way to the top! Paul Roberts of Warwick has crammed drums, bass and melody lines into three sound channels to produce a cracking rendition of the Moptops' Sixties swinger Hey Jude. The junior tunesmith has coupled accurate melody representation with clever use of the noise facilities and engineered a really listenable three minutes' worth. A well-earned platinum (3-inch) disk and twenty quid is winging its way to you as I write... "


Not emulated - original hardware and software.

Please note that  the aspect ratio for this YouTube video is 16:9 but the CPC monitor
has an aspect ratio of 4:3 so you may wish to adjust your viewing device accordingly.
Technical Support / Re: CPC 464 - very quiet speaker audio
« Last post by Audronic on Today at 02:28 »

It is also possible that the Speaker Cone is Jammed and only moves a small amount ?
If you have an other speaker that you could use as a test that might prove if I am correct.
Or keep changing the Caps C301 is also a good one to change

Good luck
Keep Safe

Technical Support / Re: CPC 464 - very quiet speaker audio
« Last post by gw0udm on Today at 00:20 »
Right a quick update

Rummaging through the junk box I've found a couple of spare capacitors and changed them out (C309 and C311) but with no improvement (see pics, although I'd only done one when I took this).

I think the one that thomas mentiones in the post above is C308 (also circled on the pics). It's covered with what looks like a blob of glue. Unfortunately I don't have any of these in stock (look like a 22uF) so will get one in.

There is also C314 which is a non-polarised electrolytic, don't have any of those either so maybe worth replacing that too.

Any other thoughts? I will probably try and get hold of one of these cheap oscilloscopes and see if I can trace the path if I can't get anywhere.

Programming / Re: Using Index registers
« Last post by roudoudou on Today at 00:13 »
use them when you want, this is not school, neither an exam. Optimisations may come later if needed...
Programming / Using Index registers
« Last post by IndyUK on Yesterday at 23:43 »
Hi folks,

Wanted to get peoples opinion on the use of the Index registers. Whenever I read any tutorial on Z80 assembly, I always find that somewhere in the index register section there is always a suggestion of not using them because they are slow. It is true to say they are slow (based on the t-states tests I've done) but, I think they are very convient. I have been experimenting with creating array types of objects (probably their primary use) and really tried to void using them but, just couldn't avoid them altogether. My code got messy and lengthy and to be honest I lost interest in continuing with the project.

So my question really is - when should we use them and when not?

Looking forward to your feedback.

Wanted to join the others to also say "nice job".

It's strange to not be able to scroll above or below what you have written.

Discovered something that maybe of interest to you. If you ever need to examine your BASIC program. Open the Assembler screen (F3) and under the File menu there is a "Read BASIC" option. That will dump your listing into the assembler window. I don't think you can edit and run it from there but, at least you can examine the code and then make the changes in the emulator screen. It's not perfect but I did find it kind of useful while bug/error fixing.

Good luck with future projects.
Hi all,

This is my first post, apologies if anyone has asked this question before.

I found a PCW 8512 in the box with the printer, keyboard and everything at a car boot sale recently for £40, which I thought was a pretty good deal. Unfortunately the machine doesn't work. When powered on, the CRT does not light up at all, both disk drive LED's are on constantly and the disk drive motors seem to run continuously. The keboard Shift Lock light does go on and off as normal when the button is pressed. The upper disk drive LED also seems to "pulse" on a regular basis. I took a video, see below:

Any ideas? Seems fairly profoundly dead but I guess could be a capacitors/power supply problem? I took it apart, cleaned the vast amount of dust from the inside, pressed down on the socketed chips on the CPU board (CPU itself and RAM) and checked that the internal fuse wasn't blown. It seemed fine although the filament inside is at quite an angle. (but did not seem broken)

Thanks in advance,

Well, if you want, give me the dsk image of exolon to replace the one used then  :)
Now, about CPC 464 compatibility, since all games in "direct file form" are extracted from dsk images, it means that they run 100% only on "Amsdos equipped" CPC with basic 1.1
Differences in memory usage (464 had a few more ram available because of the lack of amsdos, also many system variables use different places in ram) ,and different basic versions (for example, some games use loaders with basic commands that are not supported by previous basic 1.0 of CPC 464) prevent some games from loading on a CPC 464.
Also, some games require 128kb ram, so obviously these can't run on 464 models too.
In order to load these "direct file" games on 464 machines, you can either try to use the dsk image and FDC emulation, or use a snapshot file of the game, if available.

btw, added 2 more games to the list:
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