Re: Calling conventions (particularly 32-bit ARM)

On Tue, 14 Jan 2025 18:39:06 +0000, Terje Mathisen wrote:

Thomas Koenig wrote:

Scott Lurndal <scott@slp53.sl.home> schrieb:
>

https://pubs.opengroup.org/onlinepubs/9799919799/functions/sin.html
>
Clearly there are programmers who wish to be able to detect
certain exceptions, and POSIX allows programmers to
select that behavior.

>
Clearly, there is a committee which wanted to be able for people
to detect certain error conditions on a fine-grained level.
One assumes tht they did not consider the consequences.
>

Without exposing any internal discussions, it should be obvious to
anyone "versed in the field" that the ieee754 standard has some warts
and mistakes. It has been possible to correct very few of them since
1978.
>
OTOH, Kahan & co did an amazingly good job to start with, the fact that
they didn't really consider the needs of massively parallel
implementations 40-50 years later cannot be blamed on them.

CDC STAR and CRAY-1 were showing the massive parallelism well before
754 ever sat down.
In addition, the fallacy of exception and repair was also know to be
a failure well before 754 had their first meeting.

It is possible that one or two of the grandfather clauses in 754 can be
removed in the future, simply because the architectures that made those
exceptional choices are going away permanently.
>
I do not see any way to support things like "trap and rescale" as a way
to handle exponent overruns, even though that was a neat idea back then.

And just how many EVER used said feature ???

It is much more likely that we will simply switch to quad/f128 (or even
arbitrary precision) for those few computations that could need it.
>
Terje