Re: Calling conventions (particularly 32-bit ARM)

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.
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.
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
--
- <Terje.Mathisen at tmsw.no>
"almost all programming can be viewed as an exercise in caching"