Search found 9793 matches

by hoglet
Mon Jan 25, 2021 2:48 pm
Forum: acorn atom and acorn system series
Topic: Acorn System/Atom Econet
Replies: 27
Views: 1964

Re: Acorn System/Atom Econet

jgharston wrote:
Mon Jan 25, 2021 2:28 pm
Edit: Ah, you have some extra registers. So, a quick change to CPY #&E0 should fix it. I'll check when I get home.
Thanks, but I think there's a bit more to it, as you have some active code in FEE0-FEEF.

Dave
by hoglet
Mon Jan 25, 2021 11:29 am
Forum: acorn atom and acorn system series
Topic: Acorn System/Atom Econet
Replies: 27
Views: 1964

Re: Acorn System/Atom Econet

1. There does seem to be a bug in the PiTubeDirect fast 6502 implementation (Co Pro 0..3) that cause an immediate crash with a blank screen and flashing cursor. I have no idea what this is yet, and it will be hard to debug as there is no debugger support in the fast 6502 Co Pro. OK, maybe not that ...
by hoglet
Mon Jan 25, 2021 11:00 am
Forum: acorn atom and acorn system series
Topic: Acorn System/Atom Econet
Replies: 27
Views: 1964

Re: Acorn System/Atom Econet

Ooh, lots of oddness with that. PiTube Direct 6502s don't like it at all. *ATOMTUBE just clears the screen and leaves a flashing cursor, but it works on real 65C102 (in Master Turbo) or real 6502 cheese wedge (with BBC B). I can't get the Client tube source code (ClientTu/src) to load in a PiTube 6...
by hoglet
Fri Jan 22, 2021 8:58 pm
Forum: general
Topic: Today I received.....
Replies: 6092
Views: 679638

Re: Today I received.....

KenLowe wrote:
Fri Jan 22, 2021 8:38 pm
Interesting. So what's that one doing??? I'm guessing it's connected to the RGB output of your beeb?
No, not connected to a Beeb at all.

It's just running a mandelbrot demo and displaying a VGA images.
by hoglet
Fri Jan 22, 2021 6:46 pm
Forum: general
Topic: Today I received.....
Replies: 6092
Views: 679638

Re: Today I received.....

A couple of Raspberry Pi Picos from thePiHut:
IMG_2194.JPG
by hoglet
Thu Jan 21, 2021 10:29 pm
Forum: 8-bit acorn software: other
Topic: MMFS2 -> WiDFS
Replies: 5
Views: 191

Re: MMFS2 -> WiDFS

Can someone point me in the right direction? Here's the MMFS2 version of *DIN: https://github.com/hoglet67/MMFS/blob/b181a7f3b2edfb932486c3135936b14ee4a4033c/MM32.asm#L1299 All the work of parsing the filename, and following the directory FAT chain to open the file is in mm32_chain_open https://git...
by hoglet
Thu Jan 21, 2021 5:11 pm
Forum: acorn & bbc micro user group (abug) events
Topic: Weeknight 'Virtual' Dev session #9, Thursday 14th January 2021, 7pm - 10pm (GMT)
Replies: 41
Views: 1016

Re: Weeknight 'Virtual' Dev session #9, Thursday 14th January 2021, 7pm - 10pm (GMT)

dp11 wrote:
Thu Jan 21, 2021 4:50 pm
This is now public : https://twitter.com/Raspberry_Pi/status ... 9768411136 (not my work)
Oh lordy, that is impressive!

Is the board shown on the video the VGA Demo Base Board?
https://shop.pimoroni.com/products/pimo ... -demo-base

Dave
by hoglet
Wed Jan 20, 2021 9:52 pm
Forum: acorn atom and acorn system series
Topic: Atom Video to HDMI Adapter
Replies: 269
Views: 25845

Re: Atom Video to HDMI Adapter

My Atom and the Atomulator only seem to have 4 colours; green, yellow, red and black in mode 0. Is there another text mode? Yes, there is a second set of colours. To select them: ?#B002=8 To get both on the screen at once, you need to switch colour sets rapidy, in sync with the screen refresh. Ther...
by hoglet
Wed Jan 20, 2021 6:56 pm
Forum: programming
Topic: Circle floodfill ideas?
Replies: 56
Views: 801

Re: Circle floodfill ideas?

Is this any help (from Master Reference Manual part 1)? Thanks for that Ian. I came across the same algorithm in a recent ARM Basic change, begin used to convert the ELLIPSE statement arguments (angle of rotation) to an OS_PLOT call (that uses shear). https://gitlab.riscosopen.org/RiscOS/Sources/Pr...
by hoglet
Wed Jan 20, 2021 4:25 pm
Forum: programming
Topic: Circle floodfill ideas?
Replies: 56
Views: 801

Re: Circle floodfill ideas?

hoglet wrote:
Wed Jan 20, 2021 4:19 pm
I didn't explicitely choose it; it's just what GCC produced.
But I guess I could have used sqtrf(float) rather than sqrt(double).

I'll fix that next time...
by hoglet
Wed Jan 20, 2021 4:20 pm
Forum: programming
Topic: Circle floodfill ideas?
Replies: 56
Views: 801

Re: Circle floodfill ideas?

Soruk wrote:
Wed Jan 20, 2021 4:16 pm
May I borrow this for Matrix Brandy?
Sure, but I can't guarantee it's bug free.
by hoglet
Wed Jan 20, 2021 4:19 pm
Forum: programming
Topic: Circle floodfill ideas?
Replies: 56
Views: 801

Re: Circle floodfill ideas?

BigEd wrote:
Wed Jan 20, 2021 4:10 pm
Did you consider vsqrt.f32? I imagine it's faster, and suppose it should be accurate enough too, for the numbers found as pixel coords. (Edit: hmm, but is it perhaps the compiler's choice, not yours?)
I didn't explicitely choose it; it's just what GCC produced.

Dave
by hoglet
Wed Jan 20, 2021 3:49 pm
Forum: programming
Topic: Circle floodfill ideas?
Replies: 56
Views: 801

Re: Circle floodfill ideas?

I've had a go at a RISCOS-like implementation of the sheared ellipses (but in C rather than ARM assembler). Here's the filled version (which is the simpler of the two): https://github.com/hoglet67/PiTubeDirect/blob/973eda01eda53a445ab6cffd6465092b12e4517f/src/framebuffer/primitives.c#L508 Here's the...
by hoglet
Wed Jan 20, 2021 10:27 am
Forum: programming
Topic: Circle floodfill ideas?
Replies: 56
Views: 801

Re: Circle floodfill ideas?

I started to derive the prediction function for one of the cases, and it results in some pleasingly simple maths (the most complex calculation is squaring the radii, or multiplying the shear offset with the y radius, and all of these can be calculated once at the start), but it's a bit of a long sl...
by hoglet
Tue Jan 19, 2021 9:32 pm
Forum: programming
Topic: Circle floodfill ideas?
Replies: 56
Views: 801

Re: Circle floodfill ideas?

So that's the new start equation to churn through the midpoint algorithm. Don't know if that's a helpful jumping off point or not? That was just the easy bit! That's a great start. With this we could write an inefficient but correct implementation that tested each of the candidate next points to se...
by hoglet
Tue Jan 19, 2021 9:25 pm
Forum: programming
Topic: Circle floodfill ideas?
Replies: 56
Views: 801

Re: Circle floodfill ideas?

Would the ARM assembly code of RISC OS 5 be of any help? I'm looking at the code but unfortunately my ARM assembler is nonexistent :( The source file in their tree is apache/RiscOS/Sources/Kernel/s/vdu/vdugrafc,v (at least, in the snapshot I downloaded a couple of years ago) Yes, that might really ...
by hoglet
Tue Jan 19, 2021 8:06 pm
Forum: programming
Topic: Circle floodfill ideas?
Replies: 56
Views: 801

Re: Circle floodfill ideas?

I'm guessing that it might be possible to modify the axis-aligned midpoint algorithm in a way which takes into account the shear and can give every pixel, but I'd have to sit down and work through it. Either side of the ellipse would need to be calculated separately, as you only get two-fold rotati...
by hoglet
Tue Jan 19, 2021 4:12 pm
Forum: programming
Topic: Circle floodfill ideas?
Replies: 56
Views: 801

Re: Circle floodfill ideas?

Hmm, that's awkward. It looks to me like the pixels are not only not connected, but actually not in quite the right places - is it possible the distortion of the shear means the error in placement can be bigger than a half-pixel? Yes, I think this is likely. I'm also using integer arithmetic for ca...
by hoglet
Tue Jan 19, 2021 3:59 pm
Forum: programming
Topic: Circle floodfill ideas?
Replies: 56
Views: 801

Re: Circle floodfill ideas?

Yes, the ellipse is looking rather like midpoint + shear, I agree. I've had a go at implementing this now in PiTubeDirect's new VDU driver. Here's a small test on the Master: capture3.png And on PiTubeDirect (photo of HDMI output from the Pi): IMG_2185.JPG So topologically that looks correct. The o...
by hoglet
Mon Jan 18, 2021 4:26 pm
Forum: programming
Topic: Circle floodfill ideas?
Replies: 56
Views: 801

Re: Circle floodfill ideas?

I guess there could be clues in looking at how the ellipse is plotted (two opposite sides at once, pixel by pixel, or drawing around in a loop? I can't remember how the Master does it). A partly plotted ellipse: capture0.png A partly plotted circle: capture1.png So it does seem like the ellipse plo...
by hoglet
Mon Jan 18, 2021 1:02 pm
Forum: programming
Topic: Circle floodfill ideas?
Replies: 56
Views: 801

Re: Circle floodfill ideas?

There's a midpoint algorithm for axis-aligned ellipses. A sheared ellipse is also an ellipse, so it could be combining the standard midpoint algorithm with a shear (using a Bresenham type approach to accumulate the pixel offset due to the shear). No idea how horrible the maths would be to transform...
by hoglet
Mon Jan 18, 2021 12:18 pm
Forum: programming
Topic: Circle floodfill ideas?
Replies: 56
Views: 801

Re: Circle floodfill ideas?

A slightly different question....

The Ellipse plotting on the Master supports non-axis aligned ellipses:
scr2.png
Does anyone have any idea what algorithm this might be using?

Dave
by hoglet
Mon Jan 18, 2021 12:07 pm
Forum: programming
Topic: Circle floodfill ideas?
Replies: 56
Views: 801

Re: Circle floodfill ideas?

I'm currently working on a VDU driver for PiTubeDirect. Over the weekend I've been looking at the circle outline and circle fill code, mostly to try to get it to plot each pixel exactly once, so that XOR plotting works. I thought it would be interesting to compare it with the CIRCLE plotting that's ...
by hoglet
Sun Jan 17, 2021 11:53 am
Forum: 8-bit acorn hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 1373
Views: 122480

Re: RGB to HDMI using a Pi Zero and a small CPLD

SpaceFlightOrange wrote:
Sun Jan 17, 2021 11:36 am
Finally got mine built last night. I'm totally blown away by it.
Nice soldering!
by hoglet
Fri Jan 15, 2021 2:24 pm
Forum: 8-bit acorn hardware
Topic: Z80 Protocol Decoder
Replies: 224
Views: 17512

Re: Z80 Protocol Decoder

I would like to have a go with the protocol decoder to help with my ZX21 ZX81 Project (https://sinclairzxworld.com/viewtopic.php?f=6&t=3929). I am trying to get my sound chip working so I need to do some deep diving on ZX-81 operation. I would like to help improve the documentation on how to us...
by hoglet
Thu Jan 14, 2021 10:31 pm
Forum: 8-bit acorn hardware
Topic: Pstatistical Pi Peripheral Preferences Poll
Replies: 6
Views: 274

Re: Pstatistical Pi Peripheral Preferences Poll

KenLowe wrote:
Thu Jan 14, 2021 10:23 pm
For my RGB2HDMI I've only ever used the RPiZero (or it might actually be a RPiZeroW).
It's worth pointing out that only the Pi Zero/Zero W are officially supported.

Results on the multi-core Pi models are generally worse, because the memory latency is longer, and less determininstic.
by hoglet
Thu Jan 14, 2021 7:34 pm
Forum: 8-bit acorn hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 290MHz)
Replies: 1325
Views: 183321

Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 290MHz)

BTW, in Basic 1.35 which is the version included with the Native ARM Co Pro the error handler is: ERRHAN = TTRACE,TOFF,":" = TIF,TESCSTMT,TQUIT,TERROR,TEXT,TERR,",",TREPORT,"$",TELSE = TRESTORE,":!(",THIMEM,"-4)=@%:" = TESCSTMT,TSYS,"&62c82,...
by hoglet
Thu Jan 14, 2021 12:37 pm
Forum: 8-bit acorn hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 290MHz)
Replies: 1325
Views: 183321

Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 290MHz)

Just a quick note to say we discovered a couple of critical issues with Gecko on the RPI4 which prevent the Pi from booting. These have now been fixed, so if you want to use Gecko on the RPI4 you'll need to download the latest version: https://github.com/hoglet67/PiTubeDirect/releases These fixes on...
by hoglet
Wed Jan 13, 2021 11:09 am
Forum: acorn & bbc micro user group (abug) events
Topic: Weeknight 'Virtual' Dev session #9, Thursday 14th January 2021, 7pm - 10pm (GMT)
Replies: 41
Views: 1016

Re: Weeknight 'Virtual' Dev session #9, Thursday 14th January 2021, 7pm - 10pm (GMT)

I can definitely do that, it's a fairly simple system, but it's probably possible to speed it up a bit more, it's been a while since I wrote the 6502 code so it might definitely benefit from a couple more eyes on it. Is your library published anywhere? Ed and I took a quick look at it a few days ag...
by hoglet
Tue Jan 12, 2021 8:19 pm
Forum: 8-bit acorn software: other
Topic: MMFS Version 2
Replies: 498
Views: 9906

Re: MMFS Version 2

Fixed: https://github.com/stardot/b-em/commit/e8a970405606e7366e010c8f9a50829fabfd1bdd also merged to mmccard branch. Excellent.... That sorts the issue with SWMMFS+ Looking at the code in 6502.c, could you check one more thing please. I have a suspicion that when stepping through code running from...

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