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Richard Russell

Two 'lost' Morecambe & Wise programmes, discovered in Sierra Leone as 16mm black & white films, have now been restored to their original colour using BBC BASIC! Here you can see the various stages in the Colour Recovery process on a frame featuring Kenny Ball and his Jazzmen. Both programmes will be...

Richard Russell

For a long time, I would have said that it's not possible to change the vertical resolution on a Beeb but, amazingly, it was demonstrated recently in this thread: https://stardot.org.uk/forums/viewtopic.php?f=53&t=15707 . What's described in that thread relies entirely on the TV/monitor accepting a...

Richard Russell

Soruk wrote: ↑
Tue Dec 04, 2018 5:12 pm
I've not attempted to simulate BT's trade mark, of randomly adding line noise...

I did something similar in order to test the error detection and retry mechanism of my telesoftware code....

Richard Russell

Coeus wrote: ↑
Tue Dec 04, 2018 4:04 pm
gcc has been the standard, bundled with most Linux distributions

Yes, but not with Puppy Linux I think. There's a relevant thread here.

Richard Russell

Net works if using cygwin as the build environment I don't know about Jonathan's situation but I wouldn't want to install Cygwin here because it would more than likely mess up my MinGW build environment (used for BBCSDL). What feature(s) of Cygwin are you relying on? Could you create a MinGW-only m...

Richard Russell

I have released version 0.27a of BBC BASIC for SDL 2.0 (BBCSDL), for full details see the announcement here . Of particular interest may be that the 'experimental' 64-bit Linux edition now includes a reasonably complete x86-64 assembler. It supports floating point, SSE, SSE2 and SSE3 instructions (m...

Richard Russell

adrm wrote: ↑
Wed Nov 07, 2018 1:21 pm
If you had to choose, which one is the preferred choice (for a collector)?

BBC BASIC is available for the Amstrad, but not (AFAIK) for the Dragon! There's a free download here.

Richard Russell

PRINT 1 << -1 PRINT 1 >> -1 PRINT 1 >>> -1 BB4W and BBCSDL appear to give the same result as RISC OS, but it's more by luck than judgement because I don't think I've taken any special measures to to deal with 'negative' shifts. Logically, a shift count ought to be unsigned so it may well be that th...

Richard Russell

Rich Talbot-Watkins wrote: ↑
Fri Nov 16, 2018 2:57 pm
If you display that glyph without interlace (i.e. every other line) it'll just look weird.

Absolutely, just don't do it! MODE 7 characters look so 'smooth' precisely because of interlace: it doubles the vertical resolution.

Richard Russell

Even if changing this would affect almost nobody, I think Richard is right to leave it the way it is. It doesn't make a lot of sense to change it now after 18 years. When I developed 'BBC BASIC for Windows', starting sometime in 2000, compatibility with 'BBC BASIC (86) for MS-DOS' was far more impo...

Richard Russell

I've dug through the RISC OS sources and this seems to be definitive... The negative INKEY codes used by BB4W were chosen over 18 years ago, long before the RISC OS source code was made public! I wonder at what point codes for the Windows keys were added: did the RISC PC keyboard even have them? He...

Richard Russell

Soruk wrote: ↑
Mon Nov 12, 2018 4:46 pm
Certainly manually testing with PLOT 6 and PLOT 70 seem to be working OK - what plot code(s) am I missing?

I don't know if this is what Jonathan is referring to, but this seems not to work in 1.21.16 (Windows build):

Code: Select all

MODE 1
PRINT "This text should be in black on white"
GCOL 4,128
CLG

Richard Russell

So it was logical for CMOS microprocessors and other support chips to again be designed to be compatible with TTL logic levels when operated on a 5V supply. It might be helpful to make a distinction between the 74HC and 74HCT ranges of CMOS logic chips; the former do not have TTL-compatible input t...

Richard Russell

Richard Russell wrote: ↑
Wed Oct 24, 2018 10:01 pm
I've announced this elsewhere, but for confirmation I've recently updated the BBC BASIC for SDL 2.0 (BBCSDL) source code zip

Now updated to correspond to the v0.26a release. The only critical change is a bugfix in the 32-bit ARM assembler (bbasmb_arm_32.c).

Richard Russell

I guess that's what feels like the right behaviour to me now! I suspect one reason why truncating to zero is sometimes preferred is simply that it's easier (and faster) when floating-point numbers are held in a sign+magnitude format, which is conventional. A mathematician would probably favour trun...

Richard Russell

Never noticed that INT behaved like that! That's quite unusual rounding behaviour. It's not unusual for BASIC, it's the norm. In fact I know of only one BASIC which works differently which is Liberty BASIC, and its author acknowledges that it's non standard. As far as I'm aware all Microsoft BASICs...

Richard Russell

I'm not using a C cast to int, but the Brandy code offers TOINT() and TOFLOAT() conversion functions, which I am using for this. A C cast to int is surely guaranteed to truncate towards zero, so I'm puzzled by the need for a TOINT() function; what is it doing differently? BBC BASIC's INT() function...

Richard Russell

Edit: Looking at the float behaviour, it appears to be doing an INT on both arguments: No! It's an important characteristic of BBC BASIC that INT truncates towards −infinity whereas the automatic promotion of a float to an integer, such as when a bitwise operator is applied, truncates towards zero ...

Richard Russell

Not quite sure how I would implement bitwise operations on floats... What makes a compound assignment different from a conventional bitwise operator (which presumably does work with floats)? I'm pretty sure that in BB4W and BBCSDL the two work identically, except for the variable only needing to be...

Richard Russell

Edit: That M% AND= 127 construction is not valid in BBC BASIC on RISC OS 3.71 either. My recollection (and it was more than 17 years ago!) is that when adding the compound assignment operators I decided to include a more complete set than ARM BASIC does. So BB4W and BBCSDL support += -= *= /= AND= ...

Richard Russell

I've announced this elsewhere, but for confirmation I've recently updated the BBC BASIC for SDL 2.0 (BBCSDL) source code zip to correspond to the recent v0.25a release (although only the Raspberry Pi and iOS editions are currently built from this source tree). In addition to the functional changes I...

Richard Russell

But there is no need for the shell or the separate script. env should be available as an external command: $ which env /usr/bin/env so therefore it can go in the Exec line of a .desktop file That does indeed seem to work; I wasn't expecting that! The 'bbclaunch' file is therefore superfluous, and c...

Richard Russell

Usually, $HOME/.<appname>/ Thanks. So it would be better to create the bbclaunch file there, when one is necessary? If I was to adopt the alternative technique of shipping the bbclaunch file with the app, I'm unclear how (or if) using 'export' differs from using 'env' on the same line as the bbcsdl...

Richard Russell

It's common, on Unix like systems, to put executables in an area where they can't be overwritten by mistake. Wow, so it's gradually catching up with Windows then (a few decades late)?! It's just a shame that there's no such thing as a universal binary format that will install on every Linux machine...

Richard Russell

Application files... aren't. Since I supply BBC BASIC for SDL 2.0 as a zip file I really can't see what the fundamental difference is between creating hundreds of files as a result of unpacking the zip and creating one more file to assist with launching from a desktop shortcut. They both happen at ...

Richard Russell

Now you don't need to generate this file at installation time; it can be part of the package. Since (presumably) there's no alternative but to generate the bbcsdl.desktop file at installation time, I don't really understand what the problem is with generating the bbclaunch file as well. Is your con...

Richard Russell

For the record, here's the script I ended up with: #!/bin/bash MYDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" > /dev/null && pwd )" echo "[Desktop Entry] Name=BBC BASIC Comment=BBC BASIC for Linux Icon=$MYDIR/bbc256x.png Exec=$MYDIR/bbclaunch Type=Application Encoding=UTF-8 Terminal=false Categorie...

Richard Russell

It may be necessary to specify the full path to bbcsdl Yes, that was it. Somehow I assumed that the 'current directory' would be the directory containing the script, but evidently not. Specifying it absolutely worked (adding the #!/bin/bash didn't seem to make a difference, but perhaps I should inc...

Richard Russell

Soruk wrote: ↑
Thu Oct 18, 2018 6:46 pm
Can you share the script you were using to start it, in its entirety?

It's literally just that one line. Generally that kind of 'naked' script seems to work for me, and does if I simply execute it from the command line, but maybe it needs more when called from the shortcut.

Richard Russell

You're welcome! Just glad I was able to help. One more question, if I may. As discussed in another thread, some incompatibility requires the 32-bit Linux edition of BBCSDL to be executed using: env IBUS_ADDRESS=0 ./bbcsdl I haven't managed to find a way of running that from the desktop shortcut. I ...

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Morecambe & Wise restored using BBC BASIC!

Re: Mode 128x128

Re: Viewdata Service

Re: Matrix Brandy BASIC V for Linux with SDL: V1.21.16 released

Re: Matrix Brandy BASIC V for Linux with SDL: V1.21.16 released

BBC BASIC for SDL 2.0 v0.27a released

Re: Dragon 32 or Amstrad CPC 464

Re: Matrix Brandy BASIC V for Linux with SDL: V1.21.16 released

Re: Mode 7 interlace

Re: Matrix Brandy BASIC V for Linux with SDL: V1.21.16 released

Re: Matrix Brandy BASIC V for Linux with SDL: V1.21.16 released

Re: Matrix Brandy BASIC V for Linux with SDL: V1.21.16 released

Re: Logic Levels for 5V TTL Systems

Re: BBC BASIC for SDL 2.0 source code updated

Re: Matrix Brandy BASIC V for Linux with SDL: V1.21.15 released

Re: Matrix Brandy BASIC V for Linux with SDL: V1.21.15 released

Re: Matrix Brandy BASIC V for Linux with SDL: V1.21.15 released

Re: Matrix Brandy BASIC V for Linux with SDL: V1.21.15 released

Re: Matrix Brandy BASIC V for Linux with SDL: V1.21.15 released

Re: Matrix Brandy BASIC V for Linux with SDL: V1.21.15 released

BBC BASIC for SDL 2.0 source code updated

Re: BBC BASIC desktop shortcut (Linux)

Re: BBC BASIC desktop shortcut (Linux)

Re: BBC BASIC desktop shortcut (Linux)

Re: BBC BASIC desktop shortcut (Linux)

Re: BBC BASIC desktop shortcut (Linux)

Re: BBC BASIC desktop shortcut (Linux)

Re: BBC BASIC desktop shortcut (Linux)

Re: BBC BASIC desktop shortcut (Linux)

Re: BBC BASIC desktop shortcut (Linux)