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is this a mod that can be done to a standard unexpanded Beeb (and, if so, would it help?) The circuit that Acorn devised for deriving a 6 MHz clock from a 16 MHz clock (which initially I wasn't convinced was even possible without starting at a higher frequency!) inevitably gives rise to an output w...

The use of VDU7 for that and other purposes was quite popular I don't worry too much because of course 'my' BASICs aren't - and don't pretend to be - BBC Micro emulators, but rather versions of BBC BASIC adapted and optimised for modern platforms. So there are many detailed differences compared wit...

Were the BBC being cautious? As I recollect this was a serious issue and one that threatened the very existence of the BBC Micro outside the UK, not least because it wasn't thought about as early as it should have been. 'Our' BBC is probably now better known internationally than it was then, with t...

I'm way out of my depth here Me too. The beauty of SDL2 is that it provides an abstraction layer that makes all the platforms look the same to my app. I don't need to be able to write native code for any of them, and with the exception of Windows I can't. Realistically the only way I could implemen...

Is this to be expected? Probably. VDU 7, rather predictably, converts to printf ("\7") so what happens, if anything, is entirely down to how the OS handles that BEL character being sent to stdout. I don't have a lot of choice in the matter, because although the SOUND system is functional there's qu...

I believe VDU23,16 was introduced on the Master. Could be (I think VDU 23,7 was). In which case I'm happy to say that I've not implemented any RISC OS-specific VDU commands (not counting the graphics extensions as RISC OS-specific, since they were available for the BBC Micro in the GXR ROM)! I know...

danielj wrote: ↑

Fri Jan 24, 2020 9:36 am

BBC was trademarked in the US

Probably by Brown, Boveri & Cie although later the bbc.com domain was owned by Boston Business Computing.

Following up from a post in the Matrix Brandy thread: VDU23,18,3,<0|1>| will switch it - this VDU code is from RISC OS 5. OK. Generally I have not implemented RISC OS-specific VDU commands ( VDU 23,16 ... is the only one I think); this is in keeping with my general ignorance of RISC OS, having never...

Currently I don't think I'm checking for &8C You probably don't need to; I've not looked at my code for a long time either. I don't currently support the 'black text' and 'black graphics' modes (which I believe Matrix Brandy does) because they're not available on a genuine BBC Micro. For the same r...

Matrix does handle this Indeed, any MODE 7 emulator has to be independent of the order in which the characters are written (I have tested mine with reverse-order and random-order). However, it's not necessary always to process the entire 40x25 frame at once, because the potential for a change 'prop...

That was exactly it. Text was shuffled - but graphics weren't being. Ah. On the BBC Micro only the SAA5050 chip knows whether a character will be rendered as alphanumeric or as graphics, so the OS couldn't do anything different in the two cases even if it wanted to (consider the case when the chara...

Soruk wrote: ↑

Mon Jan 20, 2020 5:12 pm

- Fixed a Teletext graphics high-bit translation error.

If you are prepared to reveal, how did this error manifest itself? As far as I am aware, setting bit 7 should only have the effect of disabling the £#— character 'shuffle' (which can impact teletext graphics as well as text).

You could enter 1010: and then use a memory or disc sector editor to change the colon to a space, if you really wanted! That won't work (reliably) in any of my BASICs, because my interpreters assume that lines don't have any leading spaces. For example when the interpreter is scanning the program f...

My other option, but probably far too much work, would be to use an 8bpp 16x20 "sprite" or similar for each character SDL_ttf (there are both SDL 1.2 and SDL 2.0 versions) will create such 'sprites' for you from the Bedstead (or any other TTF or OTF) font. Indeed that's exactly how BBCSDL handles s...

a recent announcement put RISC OS under the Apache 2.0 licence (open source), and Apache licensed code can be used under the GPL OK. I don't think fonts count as 'code' from an IPR viewpoint but the Apache licence is quite permissive (more so than GPL). As for being "like" the BBC Micro, I was refe...

Your MODE 7 has different high-bit characters as shown by your screenshot. My screenshot wasn't of MODE 7, it was of the internal 16x16 ANSI character set. It's used in MODE 7 as well, by default, but of course there are no high-bit-set characters in that case (MODE 7 is 7-bits only as far as the c...

I found that if you make the following changes to my listing it will still work in BBCSDL and can also be pasted into BeebEm as a valid program I don't suppose you need the sortlib or fnusing libraries, or the associated REM!Embed directives, to make it work. They have nothing to do with fonts.

found the OTF Bedstead fonts in the lib folder, but they weren't selectable in the Set Font dialog box in the BBCSDL IDE. True. I didn't anticipate that anybody would want to use a teletext-style font for the editing pane of the IDE, so it lists only the TTF fonts. Is there any way to get the progr...

For MODE 7, Matrix Brandy follows RISC OS and the BBC. So how does that differ from mine? I presume that Matrix Brandy has the same restriction as BBC BASIC for SDL 2.0 , i.e. that pixels have to be 'square', so it's not possible to reproduce the MODE 7 font without using anti-aliasing (MODE 7 uses...

For the record there are two 'built-in' bitmapped character sets in BBC BASIC for SDL 2.0 : there's an 8x8 character set used normally in MODEs 0 to 6 and there's a 16x16 character set used in MODE 7 (if one isn't using a 'proper' teletext font like Bedstead ) and user-defined modes specifying chara...

But the cut'n'paste code above fails when pasted / *EXECed in. I agree it's reasonable for paste (if supported) to work like *EXEC. To paste a program into BB4W/BBCSDL one would use the IDE, so that's an entirely different process from *EXECing directly into the interpreter's immediate mode (and it...

should work on BBCSDL and certainly works on Brandy. Neither BB4W nor BBCSDL currently allows you to load a program using *EXEC (which AFAIK should be the only circumstance when a line having only a line number implies 'delete') so the issue doesn't arise. If Brandy is interpreting a blank line tha...

it breaks on BeebEm in both Model B and Master mode - and on RISC OS BASIC V (1.16 - RISC OS 3.71 ROM) and VI (1.75 - Softloaded)! That's surprising. Really it should have been fixed before the character set was extended to 8-bits, when the presence of CHR$(139) in a literal string became more like...

The Master certainly had all characters 128-255 defined OK, but I'm pretty sure the Model B didn't. Finding somewhere to put the pound sign whilst keeping the hash at its normal ASCII code was something that preoccupied the BBC in the very early days, and the MODE 7 musical chairs of £, # and — was...

Right now, it doesn't support it at all. All characters are 8-bit entities, like on the Beeb and ARM BBC BASIC on RISC OS. I don't think the BBC Micro had any pre-defined character 'shapes' for the codes 128-255, they were reserved solely for being user-defined (with VDU 23) as I recall. Therefore ...

a Brandy-saved (text form) file shows the correct characters, no carons. What do you consider to be the the "correct" character? If you mean the ÿ character, that's what you get if the literal strings are interpreted as ANSI but not when interpreted as UTF-8. To what extent does Matrix Brandy suppo...

when I save the tokenised program to disk as a text file and then open the text file in a native macOS text editor (I tried TextEdit and BBEdit), the CHR$255 chars all appear as carons. What would you expect it to display as?! UTF-8 encoding is virtually universal these days, it's the standard mult...

EDIT2: This looks a bit weird though: Look in the Options menu and check whether you have Unicode enabled. Since that program has literal strings containing ANSI characters (notably the CHR$255) it won't display correctly if those strings are interpreted as though they are UTF-8. That same section ...

It worked, but the MODE7 Teletext graphics were all messed up. Not a big deal, but any idea why? I'm not certain, but this comment in the code concerns me: 1320 FORj=1TO9:w3$(j)="ˇˇˇ":NEXT REM the "funny" characters are all CHR$255 I copied-and-pasted the code from the forum page you linked to, and...

That weather map with square blobs is so much easier to comprehend than modern day stuff. It's the closest I could get to the current (but not for much longer) Red Button weather maps, which are able to show symbols for cloud etc. Using colour-coded blobs seemed the best way to utilise the limited ...