Commodore 64

[FBnil]

Or would expect a lookup table in the 64K RAM?

That would have been awesome to have. Everybody pre-calculates their sines, why not give us half a sine, which could have been used for, say, volume ramping. Maybe the BASIC could have been written more efficiently to make space for it. (or use a ROM, like the C128 does - but yeah, price).

C64 38911 Basic Bytes Free -> 64*1024-38911=26625 bytes used for Basic
C128 122365 Basic Bytes Free -> 2*64*1024-122365=8707 bytes used for Basic

Enough room for Graphical basic (beyond the splitscreen graphical mode):

Commodore Software - BASIC 8 ROM

Basic 8 is a new and exciting programming environment for the C128 computer owner. It allows you to use an entirely new aspect of graphics on the ...

commodore.software

About bankswitching, and how to make your C128 have 1MB RAM

CBM: Expansion - C128 to 256kB, 512kB or 1024kB

Lot's of nice technical details. It does explain why you could add a GEOS cardridge and still have RAM to do work on the system.


Testing if your C128 has 16k or 64k video RAM
Source: https://atariage.com/forums/topic/241658-c-128-vdc-ram-upgrade/
And in general, which C128 had more video RAM

Type this line in 80 column mode:

POKE DEC("D600"),28:POKE DEC("D601"),63:SYS DEC("FF62"):SCNCLR <RETURN>

If the screen looks normal and says READY, and all that, you've got 64K
display memory. If the screen is full of 0's and looks like a programming
nightmare, you've got 16K (just hit Stop/Restore and let Mr. Kernel fix it).

Want more C128 software goodies? This site has it:

Commodore Software - Commodore 128 Specific Software

Commodore 64 & 128 applications, utilities, tools and more!

commodore.software

Some light reading (same rant as always, but very enjoyable):

Jack Tramiel Got A Good Deal, And Ruined Everything

A sideshow in the playground wars of the early 1980s over who had the best home computer lay in the quality of their onboard BASIC interpreters. Where this is being written the cream of the crop wa…

hackaday.com

 

[levi]

That would have been awesome to have. Everybody pre-calculates their sines, why not give us half a sine, which could have been used for, say, volume ramping.

Actually, sine waves have fourfold symmetry, each hoop is followed by a negative hoop and the up of the hoop is left-right symmetrical with the down of the up hoop. So a full sine wave is look up table, look up table in reverse, 0-look up table (or just invert the bits, gives you negative-1 which is close enough most of the time), 0-lookup table in reverse, then back the the start.

But I'm not sure the SID chip actually has access to the full system RAM, plus in most 8-bit systems the sin look up table is in the BASIC ROM, which might get switched out by games, at least on the 8-bit systems I'm familiar with.

 

[netcat]

Actually I might be inadvertently bullshitting (again). The oscillators could be analogue. I know the filter is.

 

[hmn]

The oscillators are digital (20 bit phase accumulator IIRC).

None of the old digital sound chips have sine wave, they only have triangle as a crude approximation

For digital sine wave, you'd use a wavetable. That can be done in software on the C64 of course (the same way sample playback is done).

 

[FBnil]

Source: https://en.wikipedia.org/wiki/MOS_Technology_6581
Source: https://www.c64-wiki.com/wiki/SID

From: http://forum.6502.org/viewtopic.php?t=5374
We get: Feed a square wave through a low pass filter, and you get a sine wave.

 

[FBnil]

Fun time!

WebSID - Make chiptune music online

An homage to the Commodore 64's SID sounds running inside your web browser

www.igorski.nl

 

[levi]

We get: Feed a square wave through a low pass filter, and you get a sine wave.

That is true of course. Filter out all of the harmonics out of any sound and you get a sine wave. The only trouble is unless you've got an extremely specific and tight low pass filter (and the classic capacitor and inductor class of filters were never that tight) you'll never filter off all of the harmonics, and since the square wave oscilator oscillates at different frequencies, unless you modify your low pass filter for each note, it won't be right for everything, and using all of that die area for differently tuned filters is still to the best of my knowledge not something anyone's done in reality. Most of these 8-bit sound chips can produce 256 different semitones of pitch which I work out to be 21+1/3 octaves which seems a little excessive, so maybe they only actually produce 128 semitones.

 

[hmn]

The oscillators are digital (20 bit phase accumulator IIRC).

Source: https://en.wikipedia.org/wiki/MOS_Technology_6581

24 bit even

We get: Feed a square wave through a low pass filter, and you get a sine wave.

Ah yes, of course!

 

[netcat]

Ha ha I figured that out with my ear, didn't need a whiteboard.

They do sound relatively tame for sid, probably the lowpass filter

 

[FBnil]

Released At :
Gubbdata 2021

Achievements :
C64 Demo Competition at Gubbdata 2021 : #1 <--- number one? That peaked my interest. It's worth your time. It got afro's and a funky tune. A bit pretentious, but hey, it's not just hot air. These guys deliver. Did I mention afro's?

Bromance

Commodore 64 Demo: Bromance by Bonzai. Released on 3 July 2021

csdb.dk

 

[FBnil]

Released 6 oct 2021 (4 days ago):


If that is too dry, watch this guy:

 

[fusion_power]

Sonic The Hedgehog! (Seaga Master System port)


The Original was my first Sonic Game on the Master System, I sadly never had a Sega mega Drive. ^^"

 

[FBnil]

Infuriatingly hard. I know some tunes, I can hum them... but the game...

 

[FBnil]

A Petscii Game! Night Drive by Data 2022 (Sorry can't give link)


Talking about cars, this tune is outstanding:

Happy new year!


There's bound to be SkyRim fans that are also C64 fans


Let's do someone else present new C64 things in 2022:

https://www.youtube.com/watch?v=MVJFTNrvelM


Here is an image:
https://www.youtube.com/watch?v=iXflAlX0Oc4


Virus lab game or something:
https://www.youtube.com/watch?v=OqY7S5t3tuc

Some cool music:
https://www.youtube.com/watch?v=g7D-7jBAhD8



https://www.youtube.com/watch?v=QalhCl0LXDY&feature=emb_rel_end
https://www.youtube.com/watch?v=prOmE_ApN-E&feature=emb_rel_end



Too bad graphics? Let's step up to Amiga:
https://www.youtube.com/watch?v=zGUgQiHfLNQ

 

[FBnil]

Whoa! PETSCII!! You remember the feud Nintendo has with Great Giana Sisters because it looked too much like Mario Bros, and then Mario Bros for the C64 came out and it was great... well....

This one is great! (for petscii)

 

[FBnil]

MW ULTRA :: Protovision - High Quality C64 Entertainment Software

MW ULTRA is an interactive action adventure game for the Commodore C64.

www.protovision.games

 

[FBnil]

Free download:

Empire Strikes Back - C64 fan version by Megastyle

A remake of the Atari 2600 version

megastyle.itch.io

"Can't believe attack of the Mutant Camels was remade - and they don't even look like camels anymore. But at least it has the same music" - FBnil 2022

 

[FBnil]

That Pig's Quest looks sweet:

 

[FBnil]

Giana Sisters TTF? Here it is (and other cool fonts):

Commodore 64 Fonts

www.kreativekorp.com

All Petscii to Unicode:

PETSCII to Unicode Mapping

www.kreativekorp.com

Be sure to visit the top-level of that directory, they have tons of goodies, like: https://github.com/kreativekorp/bitsnpicas

 

[FBnil]

unrelated: how did you find the "Sir Arthur - A brilliant PETSCII preview of Ghosts 'n Goblins for the C64" (preview) game? (sorry, can't post link)


I found it cool they used the original Ghost&Goblins song. But tbh I like the music for the C64 better. The zombies spawn too nearby, so you need to back off a few pixels to not die. Did not get past the giant.