Denial

Does your Mist/ Mistica core for the Vic20 play the speech in Berzerk MMX+? MiSTer does not :-( Yes it does, I wrote the fix myself :) And it's a very quick fix, the problem is that when the voice is turned off it should output 50% amplitude and not 0%. The 50% value is what makes POKE 36878,15 emi...

beamrider wrote: ↑Sat Jun 20, 2020 8:25 am I put a watch on $9000 in VICE and it never fired.

you are absolutely right. $9000 isn't touched at all, and if you force $9005 to $ff you see how only certain tiles are moved/shifted. The cyan stair and red ground I guess it's done with multicolor.

Very very remarkable!

I think the Vic-20 core on MiSTer is perhaps a little neglected. The inter channel distortion is much exaggerated rendering it useless to my ears. for the same reason on the MiST I added a toggle for turning off the 6KHz audio filter. It made the sound too muffled, not as brilliant as in the real V...

Mountain King doesn't appear to be update the HSCROLLPOS register @ $9000 so I am guessing it's shifting a few defined pairs of characters to achieve the fine scrolling illusion. As can be seen here, this works well on a repeating/constrained background, but not to well for arbitrary graphics IME. ...

the VIC20 core has also the noise generator reverse-engineered by Lance Ewing (there's a long thread about that here on Denial), and the pwp/viznut waveforms. I coded them for the MiST but I'm not sure they propagated to the Mister. But as I'm going to get a Mister as well, I'll check it myself some...

@chysin, very well written! A very clear picture of the carry flag, covering all the black spots. You should also tell about how carry it's used along with ADC for 16 bit addition.

haha I'm stumbling upon the same mistake over and over

but the expression "(7-SQR(50))^(1/3)" has a base less than zero and a non-integer exponent (1/3). Which is the valid reason MS BASIC throws an error. ok, but now PRINT 7-SQR(50), it gives you -.071067813, go with the VIC20 cursor and turn that into PRINT -.071067813 ^ (1/3) ... it gives ...

For an unknown reason, the evaluation of this formula fails: 10 PRINT (7-SQR(50))^(1/3)+(7+SQR(50))^(1/3) RUN ? ILLEGAL FUNCTION CALL ERROR IN 10 READY. I tried to split it into simpler terms, but it's the same. Tested in VIC 20 and in two different Z80 Microsoft Basic, the result is always the same...

I tried it, and it works as expected, that is, emulation is not accurate yet. The current status is: - on the first run (after power on) it's the same as a real VIC-20 - all successive off/on of the noise voice (e.g. POKE 36877,0 and then POKE 36877,128+x) result in a change of the "timbre"...

can we start posting again? or is still for admins?

there is in effect an inverter in between the output from the 8-bit SR and the point that it mixes with the other voices. Would this address this? no, because this only has the effect of negating the whole the output waveform (I still have to check the correct polarity, but we can address it later)...

I'm doing some more accurate tests and there is still something not right when turning off and on the noise voice repeatedly. The code for edge detection I posted previously doesn't work for some reason, so I am currently using the "rising_edge" VHDL keyword: process (noise_LFSR(0)) is beg...

thanks, I'm looking forward to test it when the new build will pop up. Are binaries generated automatically?

@groepaz this should be the fix that implements the "edge triggering" as found yesterday by Lance. I can't build VICE myself so I have not tried it directly. Compared to previous code: - added static variable "noise_LFSR0_old" that keeps track of LFSR bit n. 0 (lagged 1 step) in...