🚀 go-pugleaf

Hmm. I've just got my hands on a draft ANSI C standard, and it's quite
clear, unfortunately, that an implementation is under no obligation at
all to do this, however:

It would be very nice if the compound assignment operators (+=, -=,
*=, etc.) were atomic if applied to volatile variables. The obvious
way to achieve this would be using SWP, with an Arm3Emulator module
for processors before the Arm3 (the Arm250 DOES have the SWP
instruction, doesn't it?). I assume the Arm3Support module doesn't
catch attempts to use SWP/Co-processor 15 on older machines anyway?

Is there any prospect of such code being included in future releases
of Acorn/Norcroft C? Any news? Any comments on the suggestion?

For the time being, I'll have to make an atomic_assign macro, using
some sort of low-level swap function - not exactly efficient.

As people may have guessed from this and a previous posting, I'm
trying to get some proper concurrency going in C programs on the
Archimedes. The results may be public domain soon.

--Clive.