Ripped Dinamic tape loader

[Executioner]

Interestingly, I'm pretty sure this approach hasn't been used before on the CPC as it shows up serious bugs in both WinCPC and WinAPE as to how they handle 0x15 (pure data) chunks in CDT files. 

Can you give me more information, and perhaps a test CDT so this can be fixed?

[ralferoo]

Sure, I'll make a test CDT tomorrow. The WAV works fine in WinApe though, so I just used that...

[ralferoo]

Here's a zip that shows the bugs in both emulators (with source). Load up showbug.cdt in an emulator. This cdt is just 2 other CDT concatenated, showbug-loader.cdt (showbug.asm) and bug.cdt (bug.py). There's also bug-44100.cdt which is the same thing exported at 44100Hz instead of 6451Hz (155us per pulse).

Expected behaviour is green/orange bars at different frequencies, there's a few seconds at each before it moves on to the next multiple.

WinCPC shows orange/pink for the frequency block as it returns data in bit 5 instead of bit 7 of port #F5xx.

WinAPE shows a high frequency pattern throughout the whole block. It seems to just be toggling the bit every 155us rather than using the input data. For the 44100 version, the bit seems to toggle faster than I can read it, but I assume it's around every 22us...

There's a WAV file for both CDTs that demonstrates the expected behaviour in WinAPE.

[Gryzor]

If real tapes can't keep up with that kind of speed then it's great as an exercise, but not of much use... What's the meaning in loading a CDT in an emulator? I can think of two cases:


-there's no disk dump
-for the nice sounds fx (I do that).


So using a turbo^2 loader would be meaningless in both cases...?

[ralferoo]

If real tapes can't keep up with that kind of speed then it's great as an exercise, but not of much use... What's the meaning in loading a CDT in an emulator? I can think of two cases:

The plan is to have it usable on real tapes (although I might have to lower the speed a bit, we'll see...) If I wanted to just send from a PC soundcard to CPC it can be done much more quickly (as otla shows).

I'm only using an emulator because it's a lot quicker to develop and test that way.

-for the nice sounds fx (I do that).

I actually wrote the tape file generator first and the CPC loader later. For a while I was just listening and watching with the test program I already posted to repro the emulator bugs just because I like the noises!

I actually chose that particular baud rate as I get 9 bytes in almost exactly 312 lines so it makes nice patterns on the screen too, so I'll be a bit disappointed if I have to lower it! 

[TFM]

If real tapes can't keep up with that kind of speed then it's great as an exercise, but not of much use... What's the meaning in loading a CDT in an emulator? I can think of two cases:


-there's no disk dump
-for the nice sounds fx (I do that).


So using a turbo^2 loader would be meaningless in both cases...?

Yes right, and in case you use a MP3 device for input on a real CPC, I guess raliferoo pointed that out before.


However, a MP3 device makes only sense if you already have it and can't afford a disc drive imho. But there is of course the sentimentality effect for some I could imagine.

[dlfrsilver]

CPCE is the more accurate emu for tape loading