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Re: Moving VAX into 21 century :-)



Den 2019-08-27 kl. 15:09, skrev Paul Koning:
On Aug 27, 2019, at 8:56 AM, Anders Magnusson <ragge%ludd.ltu.se@localhost> wrote:

Morning Johnny,

...
IEEE Floating point:
     + Compatibility with rest of the world. Simple to compile programs. Possible to use otherwise unusable programs.
     - Require update of toolchain. Will not support IEEE rounding (would be too slow then).
A program that depends on a specific rounding rule is probably broken in other ways.

Can you give an example of a program that only works if the float is IEEE, but doesn't mind how rounding is done?  I'm having a hard time conceiving of a useful and reasonably reliable program for which this would be true.
Last problem I had was with Python IIRC, mostly because things won't compile cleanly and require lot of manual intervention (missing headers, missing #defines etc...).   Don't know whether it's fixed or not.

The point is that we get unneccessary and time-consuming bugs where we can avoid it with quite simple fixes.

Not to mention, how come the number of calls have blown up so much?
Much more code, and much more modular code.

Most of the code that was written like 30 years ago on VAX avoided function calls due to their slowliness, there are many comments about that in old code.  This is not the case at all anymore.
What happens if you turn on inlining?

It's in the kernel I gprof'ed.

But no reason to try to fix things with compiler options if we can fix the root cause.  CALLS will always consume unwanted cycles.

-- R


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