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Disclaimer: I am not responsible for what people (other than myself) write in the forums. Please report any abuse, such as insults, slander, spam and illegal material, and I will take appropriate actions. Don't feed the trolls.

Jag tar inget ansvar för det som skrivs i forumet, förutom mina egna inlägg. Vänligen rapportera alla inlägg som bryter mot reglerna, så ska jag se vad jag kan göra. Som regelbrott räknas till exempel förolämpningar, förtal, spam och olagligt material. Mata inte trålarna.

Apr 2015

A 9-bit pitch technique

Wed 1-Apr-2015 05:35
So you're discarding some of the pitch information to get more pitch range? jackychanmindexplosion.jpg
Linus Åkesson
Wed 1-Apr-2015 08:00
No, the total range is the same. I'm discarding some pitch information in order to be able to work with linear pitch values with high performance.

The Symbolic Links Virtual Machine

Max Porshnev
Wed 1-Apr-2015 09:34
Running the three lines of code alone doesn't seem to work. Do we need to manually create the directory listing shown?
Oh no, not manually! :)

The bitbuf

Thu 2-Apr-2015 20:20
wow, i would have one! what is make and model of the keyboard?

its a M-audio


its a pitcure of it on google

sorry for the lengt of the link


Fri 3-Apr-2015 23:27
Revisiting the BBC micro port idea.

Here's hello world:

(Story was the smallest, simplest file I had to hand, namely that discussed in https://groups.google.com/forum/#!topic/parchment/CeUK2Ry6Yvk .)

Adventures so far: the Beeb, which has an actual OS[1], uses the top of zero page for its own purposes, so the code residing there on the C64 needed splitting out into the self-modifying bit at the bottom, and the rest, which can usefully be stored at the bottom of page 1. Current zp usage is 153 bytes.

Then there was figuring out why the VM was trying to access addresses starting at 5fff00 and working downwards, well beyond the extent of the story file. Hmm, "property cache", you say?

Most recent facepalm was when I was single-stepping a crash and came across the instruction "jmp ($3dff)". This is a self-modifying jump table (jumptbl_oper) at $3d00 ($3300 on the C64 version) indexed by odd values. Early 6502s (including the 6510) perform the wraparound incorrectly, and indeed you have put the high byte at the beginning of the table as the buggy CPU in the C64 expects.

But not the more recent, non-buggy 65SC12 in the BBC Master[2] I was emulating! It does wraparound correctly, and thus loads the "wrong" value. Does this code really work on a SuperCPU?

[1] More to the point, an actual OS that can't be paged out, so any help it can provide is useful in alleviating the critical address space shortage. Also I can understand writing your own display routines, but your own *keyboard scanning code*? Is this what life is like on the C64?

[2] I would like to support a plain model B (32K should be enough for everybody, right?). But, well, if you can require a Commodore 576, I can probably get away with suggesting a Master 128 :)

Cryptic Crossword #1

Sun 5-Apr-2015 20:02
Cryptic crosswords are also very popular in the Netherlands. I'll try to solve this one but I never tried one in English before.

Variation 18

Mon 6-Apr-2015 01:57
Absolutely beautiful. I enjoyed very much!
Mon 6-Apr-2015 23:47
Great all (= idea, performance, programming, video)! Extra nice for those of us who love the movie Groundhog Day (the final piano scene).


Linus Åkesson
Fri 10-Apr-2015 22:48
Hi! Great work on the BBC Micro, and sorry for the C64-isms. I haven't actually tested on a SuperCPU, and I agree in hindsight that it might fail for the reason you suggest.

As for keyboard scanning, there's a routine in the OS, but mine supports 3-key rollover and flexible key-repeat functionality. Besides, to use the stock routine, some research would be necessary to figure out what memory areas to leave intact. With 64 kB of RAM at hand, it was easier to just implement it.

The TTY demystified

Sat 11-Apr-2015 22:14
best tty explanation ever written, hands down.

thank you so very much.

A case against syntax highlighting

Sun 12-Apr-2015 10:04
a similar opinion, advocating a more "semantic" highlighting scheme: https://medium.com/@evnbr/coding-in-color-3a6db2743a1e

A 9-bit pitch technique

jaymz julian
Mon 13-Apr-2015 07:35
I did actually implement a player which used 9bit pitch and linear slide/vibrato a few years ago, using an single octave table at c-4, and asl/lsr to get to the target octave - but a maximum of 4 rotations per note, with a hardcoded set of shifts and a jump table to pick the octave. The worst case was around the same for the shift - around 28 cycles/channel. Of course, I then fucked it up by using volume envelopes with multiplies, and channel multiplexing, and blowing out the player to around 80 rasterlines, however.

The TTY demystified

Tue 14-Apr-2015 23:21
I'm not especially new to bash programming or serial ports in general, but have never delved into stty and echo.

So I have a simple script (and I'm not sure I have the stty settings right), that should send "tx c" to the serial port. However, the best I can tell using minicom, if I perform the following from the command line:

echo tx c > /dev/ttyO1

the serial device receives:


echo aaa > /dev/ttyO1 echos aay
echo bbbbb > /dev/ttyO1 echos bbbbz
echo abcdefghijklmnop > /dev/ttyO1 echos abeefgkijkmmnoz

WHAT am I missing?

A case against syntax highlighting

Thu 16-Apr-2015 11:02
I tend to prefer syntax highlighting when typing mostly to avoid typing mistakes (the color change gives me a sort of "satisfaction" that I typed at least something properly).

One interesting thing though - 99% of the textbooks I use as reference do not use any syntax highlighting for the printed code samples -- at most they use "boldface" or something to make one part stand out ocasionally, but even this is used sparingly.

Maybe the problem with syntax highlighting is when it gets too much. Like do we really Eclipse to put something in italics if it is a static member? I hate that default setting and always turn it off. If there is just a few simple syntax highlighting elements then its fine, but if the number of distinct color categories gets to be more than a few then it quickly becomes of decreasing utility to me.

The TTY demystified

Tue 21-Apr-2015 16:45
This is best ever article on TTY. What an awesome job. Please keep writing such articles.

Bit banger

Thu 30-Apr-2015 22:29
This prick's ego doesn't allow him to reply on comments.

Surf around, you'll see he sometimes does. I think you'll see that his habit of doing awesome stuff instead of trawling forums that prevents him from replying :)