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General Category => Demos => Topic started by: Devilmarkus on 23:27, 28 December 10

Title: New CPC 464 only demo!
Post by: Devilmarkus on 23:27, 28 December 10
Hi guys,
arteffect released a cool demo for the CPC 464!
(Without AMSDOS just the pure 464)

www.youtube.com/watch?v=tTcrzwrtKF4 (http://www.youtube.com/watch?v=tTcrzwrtKF4#)

The trick: No tape or disk is needed!
Just enter:
BORDER 17
CALL &12
(ignore Operand Missing error)
CALL &14

That's all!
Read more on pouet.net (http://pouet.net/prod.php?which=56451)
Title: Re: New CPC 464 only demo!
Post by: MacDeath on 01:15, 29 December 10
How fun to consider a natural screen of death (sort of) as a Demo... :P


BTW, in what is it a "464 only" "demo" ? doesn't it work with 664 or 6128 ?
Title: Re: New CPC 464 only demo!
Post by: fano on 08:37, 29 December 10
OMG! poor beast , that remember me some "modern art".Take a snoobish attitude, explain it with unintelligible sentences and you can expect sell this for a lot of money  :P

BTW, in what is it a "464 only" "demo" ? doesn't it work with 664 or 6128 ?
Maybe because AMSDOS is not present on 464 (hear the tape relay)
Title: Re: New CPC 464 only demo!
Post by: Devilmarkus on 12:23, 29 December 10
Well it's a crash which works only on a 464 and only without AMSDOS...
Title: Re: New CPC 464 only demo!
Post by: Gryzor on 13:53, 29 December 10
OMG! My YouTube is broken!!!

I expect that if you run it on a real machine you'll get some nice sound effects from the CRT, right?
Title: Re: New CPC 464 only demo!
Post by: Devilmarkus on 15:25, 29 December 10
I expect that if you run it on a real machine you'll get some nice sound effects from the CRT, right?

Well, how can your CRT produce any sound effects? Mine only shows the screen...
But, try it, when you own a 464...
Title: Re: New CPC 464 only demo!
Post by: Gryzor on 15:32, 29 December 10
Obviously, you have never listened closely to your monitor... all those almost super-sonic sounds? Know what I mean?
Title: Re: New CPC 464 only demo!
Post by: Devilmarkus on 15:38, 29 December 10
Obviously, you have never listened closely to your monitor... all those almost super-sonic sounds? Know what I mean?

Sure, that's because Amstrad built-in a invisible sound-orchestra.
But you can only activate it with VERY special OUT commands  :P

(Yeah, I know what you mean :D )
 
Title: Re: New CPC 464 only demo!
Post by: Devilmarkus on 15:43, 29 December 10
Well, this demo is really totally bullshit!
But I find it very interesting that the crash looks always the same!
And it's done by 2 CALLs only  (The BORDER is not really necessary but makes the effect more visible)

Interesting to know is:
What happens inside the 464?
Why does it "playback" this crap and why does it not run into a reset?
And why does sometimes the tape relay click and sometimes not?

Really strange things happen in a 464 :D
Title: Re: New CPC 464 only demo!
Post by: Gryzor on 16:05, 29 December 10
Made me remember of the movie "Flatliners": move the machine just almost over the edge, then pull it back before it crashes :D
Title: Re: New CPC 464 only demo!
Post by: MacDeath on 18:18, 29 December 10
Does it harm the poor little machine ? :(
Title: Re: New CPC 464 only demo!
Post by: Toxic on 08:36, 30 December 10
well, it does harm to my poor old Arnimedes!
I just tried it and WinArnie crashed so hard that Windows 7 killed the thread. Lesson: Exact emulation  of the CRTC from our old CPC is really hard to do ;-)
Title: Re: New CPC 464 only demo!
Post by: AMSDOS on 11:45, 30 December 10
I always reckon if you want to test your emulator out without significant damage try this program out:
 
Code: [Select]
5 ON BREAK GOSUB 110
10 MODE 1:CLS:BORDER 15:INK 0,1:INK 2,7
20 FOR g=0 TO 5:FOR k=0 TO 3
30 PLOT g*106+10,k*100+50,2
40 m=90:FOR t=1 TO 23:DRAWR m,0:MOVER -m+2,2:m=m-4:NEXT
50 m=90:MOVER -45,-90:FOR t=1 TO 23:DRAWR m,0:MOVER -m+2,2:m=m-4:NEXT
60 NEXT:NEXT:OUT &BC00,7:h=0:z=0
70 WHILE z<10:h=h+1:IF h=39 THEN h=0:z=z+1
80 OUT &BD00,h:CALL &BD19:WEND
90 INK 2,INT(RND(1)*25)+2:FOR f=1 TO 10:NEXT
100 BORDER INT(RND(1)*25)+2:z=0:GOTO 70
110 OUT &BC00,7:OUT &BD00,30:END

I made some slight adjustments to it, so the screen corrects itself back to the default when you break, though this program which was posted in AA50 (Type-ins) by David Hall I vagerally recall being very smooth when I tried it on the real machine (mind you I did it on a Green Screen so maybe that may play a role?). Some of the emulators I've tried it on though do this little jerky and black line onscreen when it flicks from the top down to the bottom. Otherwise it's a nice demonstration for those to compare.
Title: Re: New CPC 464 only demo!
Post by: arnoldemu on 12:05, 30 December 10
Hi guys,
arteffect released a cool demo for the CPC 464!
(Without AMSDOS just the pure 464)

[youtube=tTcrzwrtKF4]tTcrzwrtKF4[/youtube]

The trick: No tape or disk is needed!
Just enter:
BORDER 17
CALL &12
(ignore Operand Missing error)
CALL &14

That's all!
Read more on pouet.net (http://pouet.net/prod.php?which=56451)


!!! This is the one you can get with that poke on the CPC6128. But I can't remeber the exact poke. I always thought it was poke 10,245
Title: Re: New CPC 464 only demo!
Post by: PhilZeVibe on 12:38, 30 December 10
.
Title: Re: New CPC 464 only demo!
Post by: mr_lou on 15:23, 30 December 10
How fun to consider a natural screen of death (sort of) as a Demo... :P

Well why not... The blue screen you get in Windows, is infact a true "demonstration" of Windows' (lack of) capabilities.  :P
Title: Re: New CPC 464 only demo!
Post by: AMSDOS on 23:02, 30 December 10
phi2x wrote:

This program only tests the CPC monitor emulation part, not really the core CPC emulation (CRTC, Z80, gatearray, FDC ...).
To be specific, what it tests is CPC monitor synchronization with the video signal sent by the CPC.


Wouldn't it be testing the CRTC? But yeah your right it's only testing that monitor element.

Anyway, thanks for it. Such programs are really useful to emulation authors. It would be nice to have more of these for every aspect of the CPC.

edit:
Gosh! I thought this wouldn't work on CPCBox given the CPC monitor emulation is so-so...
But I just tested it and it works flawlessly on CPCBox :o :D

edit2: The program doesn't let the monitor go out of sync as I thought primarily. CRTC vsync is only moving one char (ie: 8 rasterlines) at a time so it slips under the tolerance level of CPC monitor timings.

I'm not sure what that means!  :-[
 
I gave this program another run on my emulator last night and it was working perfectly! Not sure what was happening earlier, it might have been because the dimensions of the screen were distorted (doesn't help having a Widescreen monitor!) :(
Title: Re: New CPC 464 only demo!
Post by: PhilZeVibe on 23:48, 30 December 10
.
Title: Re: New CPC 464 only demo!
Post by: ssg on 21:41, 20 January 11
Hello everyone, as the "coder" of this, I think I need to elaborate a bit :)

The code at &12 and &14 is not meant to be run actually. the call &12 actually is just a jump to firmware which "by luck" puts a "dec bc" instruction at &b0b (which is critical for this to work).

the call &14 does the rest of work by simply turning into a rst &38 (because code at &14 corresponds to djnz &ffd0 and the code at $fffe is just a rst #38).

With the code at &14 due to then corrupt stack we end up with two distant instructions with all NOPs (thanks to Zilog making 0 -> NOP), we get the smooth animation effect in a loop:

Code: [Select]
#b0b: dec bc (from call &12)
(a lot of nops to smoothen effect)
#1ad6: jmp 2

#2: ld a,a
#3: out (c), c (yay! the effect)
#5: jp #580
(a lop of nops)
#b0b: dec bc (we're at the start)

what we end up with these calls is effectively an out loop like this:

Code: [Select]
.loop
dec bc
ds #58b
out (c), c
ds #fcb
jp loop

which can produce the same effect.

I used to impress people back in 80's with these calls which I discovered and I just wanted to share them just to prevent the effort from getting lost :)

I hope to release bigger and more enjoyable demos in the future on CPC :)

ssg
Title: Re: New CPC 464 only demo!
Post by: arnoldemu on 11:39, 21 January 11
Welcome from me, and I look forward to seeing future demos from you ! :)
Title: Re: New CPC 464 only demo!
Post by: ssg on 13:30, 28 January 11
Welcome from me, and I look forward to seeing future demos from you ! :)


thanks arnoldemu! :)
Title: Re: New CPC 464 only demo!
Post by: Devilmarkus on 22:09, 02 November 11
Hi guys,
arteffect released a cool demo for the CPC 464!
(Without AMSDOS just the pure 464)

www.youtube.com/watch?v=tTcrzwrtKF4 (http://www.youtube.com/watch?v=tTcrzwrtKF4#)

bla bla bla bla bla

Well, I was a bit bored today and tried this demo again...
I forgot that I had the SSA-1 Speech Synthesizer connected to my emulator (Or was it the DK'Tronics?)

Anyway:
Zero byte featuring hardware speech: (Watch @ 00:58)
http://cpc-live.com/zero_byte_demo/ (http://cpc-live.com/zero_byte_demo/)