Re: pthread_cond_* does not compile on i386

[Gilles Carry <Gilles dot Carry at bull dot net>]

Carlos O'Donell wrote:
> On Mon, May 5, 2008 at 2:55 AM, Gilles Carry <Gilles.Carry@bull.net> wrote:
> > I thought asm files were supposed to be only optimizations of existing C
> > code.
>
> This is not true. Did you read this somewhere?

I asked this on libc-alpha. The answer was:
>Is asm code supposed to do exactly the same as C code?

of course ... things would be broken otherwise
...
>> Should C code be the reference? Should asm be modified only when we are
>> sure C is ok? It is a problem when people change asm code without 
updating
>> the underlying C files.

you should modify whatever your target platform uses


> The asm files can be a complete implementation.
>
> For example the *context() routines are very difficult to write in C,
> possible with the use of some GCC extensions, but they are almost
> always written completely in assembly.
>
>
> > It makes sense to me to modify generic c code first and optimize afterward.
> > ie. pthread_cond_wait.c is not trivial enough to skip the generic C-coding
> > phase and go directly to asm code.
>
>
> At one point the generic C code probably worked, but after the asm
> files were written nobody bothered to build without them. As time
> passed it bit rotted.

It's a pity.


> Are you working on NPTL instrumentation? I saw the Bull presentation
> at OLS several years ago and I was *very* impressed. I would like
> nothing more than to see that code go into libc proper.

I'm not working on the same project.
I'm working on PI implementation for condvars.

Gilles.