#476 [z80] a command line option to make critical sections behave differently

[sverx]

I'm going to explain better (title is too short...): as of now, critical sections generate this before part:

    ld   a,i 
    di 
    push   af

and this after part:

    pop   af 
    ret   PO 
    ei 
    ret

but I read this will not work reliably on nmos z80s, thus I don't feel like using that.

Since I also don't need nested DI/EI I then choose to switch from critical sections to simply using inline asm, so I just place a DI before my critical code and an EI after my critical code.

But this just makes the peephole optimizer stop doing his work on that piece of code. :|

So, is there a way to make critical section generate a simple DI/EI pair?
Or could we add a command line option such as -no-nested-critical or the like?

Thanks for your info/comments on this :)

[Maarten Brock]

If you want the peephole optimizer to work over inline assembly as well you can use --peep-asm.

[sverx]

Thanks Maarten, that worked perfectly! :)

Anyway I think this one should remain as an open feature request, as I really think SDCC should support few ways to handle critical sections:

• the current one would be the 'cmos safe only' one (and the default option)
• the one with just the enclosing DI/EI would be the 'simple-no nesting' option
• a third which would be nmos safe too should be added

[Philipp Klaus Krause]

I'd prefer the one that is safe for both NMOS and CMOS to be the default.

Philipp

[Philipp Klaus Krause]

This is now handled as a bug report, since it apparently affects all Z80: [bugs:#3721].

[Philipp Klaus Krause]

A change has since been make for the --nmos-z80 case, and further measures are discussed in the bug report, so I'm closing this ticket.