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P0 Snake [sales version 64k] +3PD [2015] |
AKA :
P0 Snake [sales version] / P0 Snake Enhanced
Credits :
Intro used in this crack:
Download :
Look for downloads on external sites:
Pokefinder.org
User Comment
Submitted by tonysavon on 10 June 2015
Hi Mr. Sid.
The problem was something very stupid I had introduced at some point, and I don't really know how it could have happened. Basically, the game has different nmi-driven digi play routines. The in-game ones are classic 4 bit digis (or 2 bit on C64c), while for the intros the game plays 8-bit digis using Mahoney's cool technique. Now, all the in-game play routines exit the NMI with the trick
jmp $dd0c
where $dd0c contains $40, opcode for rti. So far, so good.
The 8-bit play routine for "welcome to p0 snake" had to be replicated in the intro, where it says "rgcd presents". That too is 8-bit, but sits in a different executable. Now, for some reason I can't really remember, that play routine, at some point, didn't use the jmp $dd0c trick, and instead acknowledged the timer NMI the old way, by reading the $dd0d register.
BUT instead of just reading it, for some reason, at some point, I introduced a R/W operation, like you would do with $d019 for a irq. Silly me.
It worked on real HW very well on all my machines, both breadbins and C64Cs (And I have many of them), but apparently, on some C64Cs, the NMI was not acknowledged. This means that the digi never really played past the first byte of the sample, so the main program, outside the NMI, was waiting indefinitely for the digi to finish before it could progress to the loading screen.
Changing my code to the classic
LDA $dd0d
restore registers
rti
fixed everything. |
User Comment
Submitted by Mr. SID on 10 June 2015
| What was the problem? Might be genuinely interesting and useful for other people to know. To avoid falling into the same trap... :) |
User Comment
Submitted by Doc Strange on 9 June 2015
User Comment
Submitted by Smasher on 9 June 2015
| handle that c64 with care pleez, Hedning! and congratulations: you are our new official betatester of all our releases :-P |
User Comment
Submitted by hedning on 9 June 2015
| All hail my queer c64c. It has a horrible VSP allergy too. |
User Comment
Submitted by tonysavon on 9 June 2015
Apparently we found the issue. The beauty of the many flavors of C64s :-)
Thanks to Hendning who happened to have one of such "not as equal as the others" C64C, and to the other people who helped! We'll deploy a fixed version soonish, just the time for more extensive tests! |
User Comment
Submitted by Heavy Stylus on 9 June 2015
| While we're at it, can someone test on a C128 :3 |
User Comment
Submitted by hedning on 9 June 2015
| OK. My test results: Of 6 different C64:s (tested with 2 different 1541U2, a 1541-II etc and with/without turbo cart) it only bugged on one, a C64C 8580 SID. Details will be sent by PM to tonysavon. |
User Comment
Submitted by Doc Strange on 9 June 2015
| For the record, this was tested before releasing. Anyway, I tried again and I had no problem loading it. So, no idea what's the problem. |
User Comment
Submitted by hedning on 9 June 2015
| No problem. I've got 3 1541 ultimates, and tonnes of drives. I'll play around a little with different hw and tell you how it went. :) |
User Comment
Submitted by tonysavon on 9 June 2015
| Yes please, Hedning, that would be really helpful. If you have a 1541u2 try to run the crt and see what happens. it would also be great if you could write this D64 on a floppy and see if it goes. You can PM me for feedback. Much appreciated, thanks a lot! |
User Comment
Submitted by hedning on 9 June 2015
| I'll make some tests too if you want. I can try about 6 c64's tonight. |
User Comment
Submitted by tonysavon on 9 June 2015
| All right, let's try to get to the bottom of this. Hopefully we can see what makes it fail on their setup. It's really fascinating that there can be so much variation among Commodore 64s: I have personally tried both the crt and the D64 on my entire Commodore 64 collection, which is made of dozens of machines, including breadbins, c64c and c64gs and it works on all of them. It even works on my C64sx! :-). whatever it is that is causing the problem, SW or HW, it must be really subtle! |
User Comment
Submitted by Heavy Stylus on 9 June 2015
Richard Bayliss tried it on his C64, both on the Ultimate 1541-II and real floppy. It crashes at the RGCD logo without playing any sound.
Jazzcat says it failed for him on three C64s and two Ultimate 1541-IIs(!)
So something is causing problems around the time that the sample should play - but ONLY on SOME C64s. |
User Comment
Submitted by Doc Strange on 9 June 2015
| I honestly had no problems running it in Emu and RH, will check again tonight anyway. |
User Comment
Submitted by Heavy Stylus on 9 June 2015
Please can people test this on real hardware? We suspect there may be a bug and we want to get it resolved before producing the carts.
On SOME C64s the game fails to play the 'RGCD PRESENT' sample on the RGCD logo, and instead just crashes. Same for this D64 crack and the original CRT.
If it fails for you, please let us know via PM. SID model etc. would be helpful to see if we can find a pattern. |
User Comment
Submitted by G-Force on 8 June 2015
User Comment
Submitted by Doc Strange on 8 June 2015
User Comment
Submitted by Scarzix on 7 June 2015
| looks very interesting, thanks for sharing. |
User Comment
Submitted by hedning on 7 June 2015
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![P0 Snake [sales version 64k] +3PD](/gfx/releases/139000/139000.gif)
