Search found 696 matches

by Richard Russell
Sun Apr 21, 2019 12:55 pm
Forum: software: other
Topic: Drawing a circle in BBC BASIC
Replies: 38
Views: 1396

Re: Drawing a circle in BBC BASIC

Well we got all of this capability (and more) in 1985 with Acornsoft's "Graphics extension ROM". 🙂 As far as I can see the 'Graphics extension ROM' provided, for the 6502, only the same functionality that came as standard in RISC OS, and didn't include elliptical arcs and sectors (only circular one...
by Richard Russell
Fri Apr 19, 2019 9:08 am
Forum: programming
Topic: What PRNG algorithm's do BBC BASIC's RND functions use
Replies: 22
Views: 330

Re: What PRNG algorithm's do BBC BASIC's RND functions use

BigEd wrote:
Fri Apr 19, 2019 4:29 am
I think this is your code:
In C, yes, but it was the x86 assembler version that I linked to earlier in the thread, and I thought that might be easier to translate to 6502 (but perhaps not). You can see from the variable names that the C code is a direct conversion from the assembler.
by Richard Russell
Thu Apr 18, 2019 10:15 pm
Forum: programming
Topic: Generating mazes (BBC BASIC)
Replies: 9
Views: 244

Re: Generating mazes (BBC BASIC)

most of the languages we used had a lower case syntax - Python (Yuk!), VB, C, Java, Pascal, etc. Yes, but I'm willing to bet that most, if not all, of those languages also require a keyword to be delimited by whitespace. For example in most BASICs PRINT is a keyword, but PRINTER is a legitimate var...
by Richard Russell
Thu Apr 18, 2019 9:07 pm
Forum: programming
Topic: What PRNG algorithm's do BBC BASIC's RND functions use
Replies: 22
Views: 330

Re: What PRNG algorithm's do BBC BASIC's RND functions use

- Basic 2 runs the shift register one bit at a time (hence 32 iterations) - Basic 4.00 runs it one bytes at a time (hence the 4 iterations) - So Basic 4.23 must run it two bytes at a time (hence only 2 iterations) And, as I said, BBC BASIC for Windows and BBC BASIC for SDL 2.0 fully unroll the loop...
by Richard Russell
Thu Apr 18, 2019 6:24 pm
Forum: programming
Topic: Generating mazes (BBC BASIC)
Replies: 9
Views: 244

Re: Generating mazes (BBC BASIC)

It was line 840 that was causing the issue. It doesn't contain any indirection operators. OK, the original program is using cell% for two quite different purposes, which is poor practice. I've edited my reply. The "Lowercase keywords" setting is enabled in my copy of BBC BASIC For SDL 2.0 (MacOS ve...
by Richard Russell
Thu Apr 18, 2019 5:58 pm
Forum: programming
Topic: Generating mazes (BBC BASIC)
Replies: 9
Views: 244

Re: Generating mazes (BBC BASIC)

the names of the variables "nextI%" and "next%" had to be changed because they began with the reserved word "next". "next" isn't a reserved word, but "NEXT" is. There should have been no need to make that change, unless you enabled the 'Lowercase keywords' setting in the Options menu. I strongly di...
by Richard Russell
Thu Apr 18, 2019 4:02 pm
Forum: programming
Topic: What PRNG algorithm's do BBC BASIC's RND functions use
Replies: 22
Views: 330

Re: What PRNG algorithm's do BBC BASIC's RND functions use

I'm fairly sure this is the Basic 4 code. I find it somewhat puzzling that it's a loop executed twice: LDY #$02 .L83D5 ... DEY BNE L83D5 In the earlier 6502 BASICs RND is a loop executed 32 times, each corresponding to 'clocking' the LFSR, which is a naïve way of de-correlating consecutive values. ...
by Richard Russell
Thu Apr 18, 2019 1:45 pm
Forum: programming
Topic: Generating mazes (BBC BASIC)
Replies: 9
Views: 244

Re: Generating mazes (BBC BASIC)

The program also works in BBC BASIC For Windows but fails in BBC BASIC For SDL 2.0 (MacOS version 1.02a) The MacOS edition of BBC BASIC for SDL 2.0 is 64-bit BBC BASIC (current versions of MacOS will still run 32-bit apps, with a warning, but before too long 64-bit apps will be mandatory). That mea...
by Richard Russell
Thu Apr 18, 2019 12:55 pm
Forum: programming
Topic: What PRNG algorithm's do BBC BASIC's RND functions use
Replies: 22
Views: 330

Re: What PRNG algorithm's do BBC BASIC's RND functions use

There was a change in Basic 4 The change didn't affect the PRNG algorithm as such, since RND (with no parameters) returned the same integer values as it had previously - and indeed the same as are returned by every other version of BBC BASIC that I know of. For example running this code: seed% = RN...
by Richard Russell
Thu Apr 18, 2019 8:28 am
Forum: emulators
Topic: BeebEm Mac - Info
Replies: 53
Views: 2095

Re: BeebEm Mac - Info

Unless something drastic happens I can't see me renewing my Apple developer membership so unless someone else steps up to sign the application then we're going to be back to square one when the next version of the OS comes out. If you simply need somebody with an active Apple Developer account then...
by Richard Russell
Sun Apr 14, 2019 7:10 pm
Forum: software & utilities for the pc, mac or unix
Topic: BBC BASIC for SDL 2.0 version 1.02a released
Replies: 5
Views: 380

Re: BBC BASIC for SDL 2.0 version 1.02a released

can you say what your wish list is? The main outstanding items are: 1. Floating point and SIMD instructions (NEON) in the ARM assembler. Currently I can't adapt the 'mandel.bbc' example to run on the Raspberry Pi or (ARM) Android because of this omission. 2. Plot filled segment (PLOT 168-175), whic...
by Richard Russell
Sat Apr 13, 2019 4:47 pm
Forum: software & utilities for the pc, mac or unix
Topic: BBC BASIC for SDL 2.0 version 1.02a released
Replies: 5
Views: 380

Re: BBC BASIC for SDL 2.0 version 1.02a released

RobMcK wrote:
Thu Apr 11, 2019 6:37 pm
Thank you for your continued efforts with BBC BASIC for SDL 2.0
BBCSDL has reached something of a plateau, in that the only items currently remaining on the 'wish list' are things I don't know how to do! Is there anything you would like to be added that might enhance its appeal or usefulness?
by Richard Russell
Fri Apr 12, 2019 2:52 pm
Forum: emulators
Topic: Sound comparison (CTRL-G) real Elk and 4 emulators
Replies: 6
Views: 268

Re: Sound comparison (CTRL-G) real Elk and 4 emulators

Rich Talbot-Watkins wrote:
Fri Apr 12, 2019 1:19 pm
Might be to do with the window function I used.
[pedant]There's no such thing as a 'Hanning' window! A 'Hann' window yes, but calling it 'Hanning' for its similarity with 'Hamming' is not to be encouraged.[/pedant]
by Richard Russell
Fri Apr 12, 2019 8:56 am
Forum: general
Topic: The Scaffold on BBC Breakfast
Replies: 0
Views: 125

The Scaffold on BBC Breakfast

If anybody watched The Scaffold on BBC Breakfast this morning (sadly Roger McGough wasn't there), yes the clips from the recently discovered Talk of the Town recording were colour-recovered using my BBC BASIC program. This was the rough colour recovery, warts and all, which normally gets cleaned up ...
by Richard Russell
Thu Apr 11, 2019 9:52 pm
Forum: emulators
Topic: Sound comparison (CTRL-G) real Elk and 4 emulators
Replies: 6
Views: 268

Re: Sound comparison (CTRL-G) real Elk and 4 emulators

And the waveform of a real Elk is definitely not square so it produces a 'richer' sound. Whilst that may well be true, it's perhaps worth noting that the waveform being very different doesn't imply that the sound will be different. For example these two waveforms should sound identical, because the...
by Richard Russell
Sat Apr 06, 2019 10:13 pm
Forum: projects
Topic: Viewdata Service
Replies: 146
Views: 9955

Re: Viewdata Service

It's to ensure when something is entered (e.g. location page on Telstar's Weather page) it's echoed back. It's not caused any issues so far, but perhaps it's unnecessary? I would have expected that kind of 'echoing' to be handled by the service itself (Telstar in this case) not by the telnet server...
by Richard Russell
Sat Apr 06, 2019 5:07 pm
Forum: projects
Topic: Viewdata Service
Replies: 146
Views: 9955

Re: Viewdata Service

I can't replicate this at the moment with either the Matrix Brandy client, nor your telstar.bbc on Android. It's back to normal here today. I won't worry about it unless it happens again. I send FF FD 03 FF FD 01 OK, so you are sending IAC DO ECHO as well. I would not have expected echoing by the s...
by Richard Russell
Fri Apr 05, 2019 9:26 pm
Forum: projects
Topic: Viewdata Service
Replies: 146
Views: 9955

Re: Viewdata Service

Just as a point of interest, Telstar throttles page responses to 1200 baud, however, if a Telnet type client is detected by the parser Telstar runs at full speed. Usually, my 'telstar.bbc' client renders at full speed but this evening it seems to be throttled to 1200 baud. Has something changed you...
by Richard Russell
Fri Apr 05, 2019 2:31 pm
Forum: projects
Topic: Teletext to Viewdata server
Replies: 12
Views: 373

Re: Teletext to Viewdata server

Soruk wrote:
Fri Apr 05, 2019 11:43 am
Absolutely - it also gets a mention on P903.
Thanks. Annoyingly, immediately after posting my comment I found another bug in telstar.bbc (the worst kind: statistical and intermittent). :oops: Now fixed in v0.23.
by Richard Russell
Fri Apr 05, 2019 11:41 am
Forum: projects
Topic: Teletext to Viewdata server
Replies: 12
Views: 373

Re: Teletext to Viewdata server

Soruk wrote:
Fri Apr 05, 2019 10:18 am
on BBCSDL's telstar.bbc it's F1 to reveal, F2 to conceal.
Can I take this opportunity to mention that telstar.bbc has recently been updated to include Teefax in the list of services, plus a couple of minor improvements.
by Richard Russell
Fri Apr 05, 2019 8:58 am
Forum: off-topic
Topic: Sound Export
Replies: 35
Views: 1143

Re: Sound Export

I have all three platforms available here but only on Windows do I have an audio recorder program that I have written myself (in BBC BASIC) This thread triggered me to rectify that situation. I have now ported my audio recorder program from BBC BASIC for Windows to BBC BASIC for SDL 2.0 , so it is ...
by Richard Russell
Thu Apr 04, 2019 1:32 pm
Forum: software & utilities for the pc, mac or unix
Topic: BBC BASIC for SDL 2.0 version 1.02a released
Replies: 5
Views: 380

BBC BASIC for SDL 2.0 version 1.02a released

I have released version 1.02a of BBC BASIC for SDL 2.0 , the cross-platform programming language for Windows, MacOS, Linux, Raspberry Pi, Android and iOS. The changes in this version are as follows: IDEs / Compiler : SDLIDE: F10 now displays the context menu at the position of the text caret; this e...
by Richard Russell
Wed Apr 03, 2019 8:01 am
Forum: projects
Topic: Teletext to Viewdata server
Replies: 12
Views: 373

Re: Teletext to Viewdata server

Soruk wrote:
Wed Apr 03, 2019 7:03 am
In the meantime, I've made the change to the server so if the line is blank (a single space) it just sends 0x0A instead.
That's excellent. :)
by Richard Russell
Tue Apr 02, 2019 10:12 pm
Forum: projects
Topic: Teletext to Viewdata server
Replies: 12
Views: 373

Re: Teletext to Viewdata server

Really, I'm just making it up as I go along. In the absence of a formal specification I think it's reasonable to assume that the way CommSoft and the official BBC Micro Prestel System behave in this respect (which I trust is the same!) can be taken as a reference. Perhaps somebody with the appropri...
by Richard Russell
Tue Apr 02, 2019 9:22 pm
Forum: projects
Topic: Teletext to Viewdata server
Replies: 12
Views: 373

Re: Teletext to Viewdata server

some other clients were putting blank lines in! So - to work around this, after every line is sent, a 0x08 is transmitted so that irrespective of the line-wrap mode it displayed correctly. I agree, it's a weird hack, but I'm not really sure how else to approach this. Very cunning! I assume that the...
by Richard Russell
Tue Apr 02, 2019 4:21 pm
Forum: projects
Topic: Teletext to Viewdata server
Replies: 12
Views: 373

Re: Teletext to Viewdata server

My telstar.bbc client (as supplied with BBC BASIC for SDL 2.0 ) isn't behaving exactly as it should when displaying Teefax pages via your gateway. I think I've traced the cause to how you are handling double-height text; I would not have expected you to be sending anything in the second row of a dou...
by Richard Russell
Thu Mar 28, 2019 10:08 pm
Forum: software: other
Topic: Snowflakes (BBC BASIC)
Replies: 4
Views: 297

Re: Snowflakes (BBC BASIC)

To get the right colours on a platform lacking a hardware palette (e.g. BBC BASIC for Windows or BBC BASIC for SDL 2.0) add a CLS (VDU 12) in line 130:

Code: Select all

  130   VDU19,0,4,0,0,0,12
by Richard Russell
Wed Mar 27, 2019 2:02 pm
Forum: software: other
Topic: Drawing a circle in BBC BASIC
Replies: 38
Views: 1396

Re: Drawing a circle in BBC BASIC

Though also to be fair Dragon Basic, is Microsoft basic for the 6809, which was available for the Tandy CoCo (which the Dragon is an effective clone of), which was out in 1980. I would expect graphics statements to be machine-specific language extensions, and therefore the origin and date of the un...
by Richard Russell
Tue Mar 26, 2019 2:34 pm
Forum: software: other
Topic: Drawing a circle in BBC BASIC
Replies: 38
Views: 1396

Re: Drawing a circle in BBC BASIC

The Speccy, Dragon and Oric all have a circle command I believe. To be fair they all came out after the BBC Micro, and I suspect the Spectrum influenced subsequent machines. For example Oric 1 BASIC supports the INK and PAPER statements which I think derive from Spectrum BASIC. The graphics feature...
by Richard Russell
Tue Mar 26, 2019 9:54 am
Forum: software: other
Topic: Drawing a circle in BBC BASIC
Replies: 38
Views: 1396

Re: Drawing a circle in BBC BASIC

What kind of supprises me is that BBC basic doesn't have a Circle command The CIRCLE statement was introduced in BBC BASIC 5. All 'modern' versions of BBC BASIC support it. as most other basics of the time did. Most? If that really was the case I would have expected there to be pressure for BBC BAS...