Search found 2390 matches

by BigEd
Mon Mar 18, 2019 5:08 pm
Forum: software & utilities for the pc, mac or unix
Topic: Matrix Brandy BASIC V for Linux with SDL: V1.21.19 released
Replies: 520
Views: 21518

Re: Matrix Brandy BASIC V for Linux with SDL: V1.21.19 released

With Basic VI (1989) from RISC OS Pico on a Pi:

Code: Select all

BasicVI: 3.1415926535897931
by BigEd
Mon Mar 18, 2019 8:09 am
Forum: off-topic
Topic: Computing pi in a very unusual way
Replies: 7
Views: 262

Re: Computing pi in a very unusual way

A kind person provided a clue:
Thomas Klemm wrote:
... a clue would be nice! Please?
A002491
Thanks! That led to Kevin Brown's Rounding Up To PI - MathPages.
by BigEd
Sun Mar 17, 2019 10:41 pm
Forum: general
Topic: Some interesting Steve Furber observations
Replies: 23
Views: 3158

Re: Some interesting Steve Furber observations

Just for completeness, a couple more Furber quotes over here and here in a nearby thread specifically about the Electron. And some more in this Register article about the Elk: On the BBC Micro we had problems with the video processor overheating, but we understood why that was the case in great deta...
by BigEd
Sun Mar 17, 2019 1:07 pm
Forum: software: new games
Topic: Doom?
Replies: 69
Views: 2484

Re: Doom?

Extraordinary, and very impressive indeed. VideoNuLA looks likely to become a must-have!
by BigEd
Sat Mar 16, 2019 10:04 am
Forum: software: other
Topic: PLAY Command
Replies: 2
Views: 174

Re: PLAY Command

I like this, a lot! Haven't had a chance to have a go yet.
by BigEd
Fri Mar 15, 2019 11:01 pm
Forum: off-topic
Topic: Computing pi in a very unusual way
Replies: 7
Views: 262

Re: Computing pi in a very unusual way

Yes, it was originally presented using a ceiling function, but Basic lacks that, so I flipped some signs:

Code: Select all

       1   DEF FNP(N) 
       2       T = N 
       3       FOR I = N-1 TO 2 STEP -1 
       4             T = CEIL(T/I)*I
       5       NEXT I
       6       FNP = N*N/T
       7   END DEF
by BigEd
Fri Mar 15, 2019 10:13 pm
Forum: off-topic
Topic: Computing pi in a very unusual way
Replies: 7
Views: 262

Re: Computing pi in a very unusual way

"The most unexpected answer to a counting puzzle" - a good one!
by BigEd
Fri Mar 15, 2019 9:20 pm
Forum: off-topic
Topic: Computing pi in a very unusual way
Replies: 7
Views: 262

Computing pi in a very unusual way

This program by Valentin Albillo is quite surprising - any idea what's going on?
Albillo-pi-basic.png
by BigEd
Fri Mar 15, 2019 12:18 pm
Forum: development tools
Topic: Ghidra disassembler
Replies: 4
Views: 143

Re: Ghidra disassembler

The HN discussion has this to say: Why this is important (for those uninitiated): Ghidra is basically the first real competitor to IDA Pro, the extremely expensive and often pirated state-of-the-art software for reverse engineering. Nothing else has come close to IDA Pro. Ghidra is open-source, IDA ...
by BigEd
Thu Mar 14, 2019 10:07 am
Forum: wanted
Topic: Wanted - datacentre
Replies: 19
Views: 384

Re: Wanted - datacentre

This is encouraging:
Once all sold out, I will make the DataCentre system open source, and upload all the design files to GitHub (If I can work out the right way to do it!), so if someone else want's to make some, or redesign it, they will be free to do so.
by BigEd
Mon Mar 11, 2019 11:39 am
Forum: off-topic
Topic: RCM on the TV
Replies: 2
Views: 157

Re: RCM on the TV

(That is, the Retro Computing Museum in Leicester. I visited a couple of years ago - here are some photos.)
RCM-2017.png
by BigEd
Sun Mar 10, 2019 6:06 pm
Forum: upcoming and recent events & exhibitions
Topic: Wakefield RISC OS show 27/4/19
Replies: 68
Views: 1804

Re: Wakefield RISC OS show 27/4/19

We didn't quite manage to do this at the Bristol show, but I wanted to show off some Beebs with Pi second processors which can therefore do 32-bit computing, whether Basic on ARM or one of the high level languages on the Nat Semi 32k copro (Lisp Fortran C Pascal Basic). There is a showreel program ...
by BigEd
Sun Mar 10, 2019 7:20 am
Forum: software: other
Topic: Drawing a circle in BBC BASIC
Replies: 19
Views: 709

Re: Drawing a circle in BBC BASIC

Ah, thanks, that explains the 31 instead of 32!
by BigEd
Sat Mar 09, 2019 10:44 pm
Forum: software: other
Topic: Drawing a circle in BBC BASIC
Replies: 19
Views: 709

Re: Drawing a circle in BBC BASIC

So, indeed, the more expected 120 step=2*PI/31 works about as well, because of a coincidence of how close 50 is to 16 times pi. Changing both the '31' to '32' results in a slightly more circular circle, perhaps not just because 32 is a larger number, perhaps because the pixels line up more evenly. 1...
by BigEd
Sat Mar 09, 2019 9:15 pm
Forum: software: other
Topic: Drawing a circle in BBC BASIC
Replies: 19
Views: 709

Re: Drawing a circle in BBC BASIC

This looked very odd to me: step=(2*PI/90)+50 because I can't think how 50 radians should come into play. I'd be interested to see the new version in text form. I'd wonder if it would 'better' to divide the circle into 32 and draw 8 lines (or triangles) at a line by taking advantage of symmetry. May...
by BigEd
Sat Mar 09, 2019 3:33 pm
Forum: hardware
Topic: Datacentre, gosdc, gotek etc??? Which?
Replies: 13
Views: 325

Re: Datacentre, gosdc, gotek etc??? Which?

Is it worth noting that Gotek is so compatible that it runs at the same speed as a real floppy, including seek time? (Correct me if I'm wrong!)
by BigEd
Fri Mar 08, 2019 9:50 pm
Forum: hardware
Topic: Cheaper 2nd processor in preshadow days?
Replies: 16
Views: 567

Re: Cheaper 2nd processor in preshadow days?

Hmm, you've just brought to mind a horrible idea for adding memory to the 64k coprocessor: separate instruction and data. Allow at least 16k, maybe 32k, of high memory overlay which is only accessed for program (opcode and operand bytes) whereas data accesses always access the base 64k. It makes in-...
by BigEd
Fri Mar 08, 2019 1:20 pm
Forum: hardware
Topic: Cheaper 2nd processor in preshadow days?
Replies: 16
Views: 567

Re: Cheaper 2nd processor in preshadow days?

Interesting to see in that July '87 price list no mention of the cheesewedge 6502. There is the Z80 and the 32016, but the faster 6502 option is limited to the Turbo for the Master.

Any idea if the Turbo was cheaper than the cheesewedge, when they were both sold?
by BigEd
Fri Mar 08, 2019 12:36 pm
Forum: hardware
Topic: Cheaper 2nd processor in preshadow days?
Replies: 16
Views: 567

Re: Cheaper 2nd processor in preshadow days?

Great work digging up older price lists, thanks!
by BigEd
Fri Mar 08, 2019 10:41 am
Forum: general
Topic: Where is everyone? An information gathering topic
Replies: 112
Views: 23831

Re: Where is everyone? An information gathering topic

The Canada West meetups show that two's enough!
by BigEd
Fri Mar 08, 2019 10:39 am
Forum: hardware
Topic: Cheaper 2nd processor in preshadow days?
Replies: 16
Views: 567

Re: Cheaper 2nd processor in preshadow days?

I was going to suggest that games aren't a great application for a second processor, but RobC has been busy demonstrating that with a sufficiently fast second processor, there's enough bandwidth in the Tube to shuttle graphics updates and user events fast enough to play 8-bit games, the kinds of gam...
by BigEd
Fri Mar 08, 2019 8:07 am
Forum: off-topic
Topic: Seeking 290 programs for Sinclair Cambridge Programmable
Replies: 1
Views: 170

Re: Seeking 290 programs for Sinclair Cambridge Programmable

Just to note, it's the Sinclair Cambridge Programmable with 36 steps that I'm interested in here, not the earlier and larger Sinclair Scientific Programmable with only 24 steps (and no branch or loop). That machine's "program library" can be found here . There's a functional JavaScript emulator of t...
by BigEd
Fri Mar 08, 2019 7:28 am
Forum: software: other
Topic: Acornsoft C
Replies: 17
Views: 549

Re: Acornsoft C

You have an = instead of == on the RHS of that expression - might that be confusing the compiler? Is there any more to the error message?
by BigEd
Wed Mar 06, 2019 9:52 pm
Forum: hardware
Topic: Beeb 1MHz Bus FPGA Adaptor
Replies: 35
Views: 810

Re: Beeb 1MHz Bus FPGA Adaptor

The 1MHz Owl Dongle might be the killer app.
by BigEd
Wed Mar 06, 2019 11:49 am
Forum: software: other
Topic: When (and why) did PLOT 8-15 change?
Replies: 13
Views: 499

Re: When (and why) did PLOT 8-15 change?

Presumably it's faster, and if you're in an XOR mode it's also the same behaviour. And as a bonus, it matches the User Guide! (It is unexpected to see a change though.) Now, was the User Guide a specification, of sorts? Or was there a firmer specification somewhere which specified double-plotting? (...
by BigEd
Mon Mar 04, 2019 8:28 am
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 664
Views: 28283

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

Now that does look rather special - well done! I take it this approach has the feature of persistence - that most frames don't need the special code in the picture, because all the palette changes have already been scripted?
by BigEd
Sun Mar 03, 2019 8:25 am
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 664
Views: 28283

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

It may be a stretch to wrestle it to the ground, but I think the Pi's videocore should be able to overlay two frame buffers (indeed, it should be able to apply a scanlines effect as a post-process, but that probably takes even more research and experiment!) Or, as you say, a bit of assembly code mig...
by BigEd
Sat Mar 02, 2019 9:12 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 664
Views: 28283

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

(Interesting idea though to get rid of the line-doubling. That sounds great to me, and I personally wouldn't miss the scan lines.)
by BigEd
Sat Mar 02, 2019 9:10 pm
Forum: hardware
Topic: RGB to HDMI using a Pi Zero and a small CPLD
Replies: 664
Views: 28283

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

OK, if the Pi's frame buffer is only 4 bits then that's a somewhat different story! I'm thinking that making the interface one of specifying lines where things will happen should remove the need to do any accurately-timed updates: the problem is now a spatial one. Which means it affects what we writ...