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Not necessarily. With highly proprietary stuff, there may be "free" and "paid-for" client software, with the former having some of the latter's features deliberately nobbled. BitKeeper was an example of such (although Andrew Tridgell's Open Source client managed to outperform even the paid-for one).

I got stuck with the photoplotting stuff and ended up going on a wild tangent, rewriting the maths library (it now does multiplications in about half the time it used to, and divisions in something nearer a third than half the time it used to. Getting this to work required rearranging zero page loca...

That and all .....

This is why, when you ask a user to supply a filename, you should never, ever presume to know what is or is not a valid filename.

The most important tool you need for host-side development is a good text editor, because you will be using it. A lot. Ask six different people, and you will get twelve different answers. Try them all, and any more you can find; and whichever one you choose, be sure occasionally to have a play with ...

If you were going to do 640*256*4 or 320*256*16, you really would need a framebuffer that looks as though it is composed of 20480 16-bit words of RAM. The circuitry is capable of sending 640 pixels to the screen on each scanline; it just can't read more than 80 bytes from memory in that time. But if...

I acquired this new toy today: IMG_20200904_231820_1280.jpg It is not quite as perfect as it looks; as explained by the seller, some of the keys are not working. However, the action on them is perfect, so they probably just need a squirt of Servisol and a bit of Micro Olympics to get them going agai...

Well, it seems to work, behaves exactly as expected and does not do anything too crazy with the stack either (as shown by selecting a graphics mode and changing HIMEM to somewhere inside the framebuffer).

I think we've all seen assembler code like this: .add16 CLC .adc16 JSRadd16_1 .add16_1 LDAwkspace,X ADCwkspace,Y STAwkspace,X INX INY RTS with multiple entry points into the same code, so two JSRs can hit the same RTS. Can you do something similar in BASIC, with a DEFPROC between another DEFPROC and...

Mmm, I'm sure there's some good stuff in there! I think I even have a use for the CRTC stunts they pulled .....

See VList source code. I'm certainly not claiming any originality on this idea, and it would be disingenuous of me to pretend that the name jgharston did not crop up a few times while I was searching for information on how to do this! However, as a fan of doing things the hard way just for fun, I t...

Although I'm currently using BeebAsm for BCP development, and it's going very nicely, I do not want to abandon the idea of it being buildable on the target side. Otherwise, I am going to wind up with not so much a BBC Micro app, but a PC app that uses a special tool chain (BeebAsm and friends) and r...

In case you need help with detokenising line numbers, this is how DFSbuster does it: Line numbers in a GOTO / GOSUB / RESTORE are tokenised according to a slightly weird scheme to ensure they don't clash with anything else that might look like a token; elsif ($code == 141) { # 141 = line number ($ln...

^ This is caused by BeebEm trying to detect double-sided discs. It gets tripped up when sector 10 contains mostly ASCII data (i.e. values &20-&7F), as often happens in games that have instructions in their loader. Ah! That might go some way towards explaining some of my past BeebEm woes with disc i...

There's a lot to be said for using the video system as a diagnostic aid, by loading a file directly into screen memory -- especially now we're not using fuzzy CRTs anymore, but precise LCDs, where each individual pixel shows up with beautiful sharpness. Graphics data will be pretty obvious if the sc...

In short, not code (does anyone actually use BIT instructions?), so it looks like it's data of some sort ... I find BIT very useful! It performs a bitwise AND between the accumulator and the contents of some address (it only supports absolute addressing, though the address can be short or long), bu...

Well, I'd rather run an ancient version of a piece of software that I built myself, than one that was compiled by someone I don't trust.

What happened to BeebEm in the meantime? Did it get too dependent on Windows-specific libraries?

I don't think we're in disagreement here. A program has multiple requirements which come into play once you satisfy "works at all". These might include fast time to deployment, small memory footprint, fast execution and ease of maintenance; and no non-trivial program can be expected to be able to sa...

All I will say is that if the means to an end don't matter, many of the extensions I've made to BBC BASIC could be classed as useless, because they provide a 'nicer' way of doing something rather than a capability that it didn't have previously. Surely the existence of an alternative (and therefore...

Well, my code deliberately includes a section to read data from anywhere on screen (as long as it be byte-aligned horizontally), given X and Y co-ordinates, width and total length, and store it linearly in a contiguous block in memory. This is intended for storing the background that was there befor...

My preferred approach would be this. Put all accesses to MODE 7 sixels in a PROC (for write) and an FN (for read); don't expose the underlying array(s) at all, so their format is irrelevant. Yes, that's undoubtedly the "proper" way to do it. But we're both veteran programmers; we've already had all...

The conversion from X and Y coordinates to array index may well be simplified, but when you eventually want to update the screen from your 'pixel' array you will have to perform the more complicated conversion from pixel to character anyway, and this time on every pixel not just the ones that have ...

What is this "file" menu of which you speak? It's not in the version of BeebEm I've been using, where the "f12" menu looks like this: So is there a newer version?

true that only 6 bits in each character correspond to sixels, the other 2 don't, but nevertheless there's a one-to-one correspondence between sixel and memory bit, so where does the advantage of a separate array arise? The difference is in the way the array is accessed; i.e., whether the array inde...

The point of my separate array is not performance -- it will be demonstrably fractionally slower and use up more memory -- but that it is organised by pixels, not characters; so you can read the state of any pixel directly. You could use a FN to accept pixel co-ordinates, work out the position of th...

If you have BeebAsm then try creating this file as amx.6502 ORG &8000 .beginrom INCBIN "AMX.rom" .endrom SAVE "AMX", beginrom, endrom with AMX.rom in the same folder; and then $ beebasm -i amx.6502 -do amx.ssd to create an SSD image. There's even https://github.com/JulieMontoya/DFSBuster if you have...

Instead of faffing about trying to read data from the screen, why not use an array to keep a separate copy of what should be on the screen? After all, memory is not precious anymore. You might as well let the computer make it easier for you -- even updating the array and the screen at the same time ...

If you use GIMP at a high enough magnification to edit individual pixels, then it's pretty easy to keep everything aligned, assuming you know your multiplication tables for the height and width you want your sprites to be! Then you need a way to get an image from a format GIMP understands, to BBC fo...

I think I've got the business of exporting labels sorted. It took just a few lines of Perl to create a file of the form I needed from the beebasm -v output! Once I've seen a line that matches /^\s*.*\.([A-Za-z_][A-Za-z\d_]*%?)/ then I know to look for /^\s*([0-9A-F]+)/ on the next line. Now I just n...

O.M.G. BeebAsm really is the absolute business! It was the work of about a couple of hours, fragmentated throughout the weekend, to move the Source Code of BCP to BeebAsm; and it builds and works absolutely fine. It probably helps a lot that BeebAsm suits my existing coding style fine. There was one...

That's pretty good! I actually had a go at dithering colours myself. My first attempt suggested "you'll have to try harder than that", but then the day job got in the way of my adventures with the ImageMagick documentation (no point importing a dog from a library and barking yourself, and all that; ...