On 2009-03-14 02:45:27 -0400, Walter Bright <newshou...@digitalmars.com> said:
Don wrote:
That's true, but if you're in a floatingpoint module, and you call a
non-floatingpoint module, it's your responsibility to make sure that
the rounding mode is back to normal. You're saying that you don't care
about the status flags. So it's your own fault if you get surprising
results.
The primary use for adjusting the rounding mode is for things like
implementing interval arithmetic. Thus, it's only ever used for small
functions.
Perhaps we can go with something simpler. If you call a pure function,
then the modes must be set to their defaults.
Just dumping another idea in the suggestion box. Perhpas for all
functions the compiler could store the floating point flags it expects
when called. All functions would expect the default flags, but there
could be a way to attach different flags to a function. Then, the
compiler makes sure that when calling that function the flags are set
properly.
The net result is that if you keep the default on every function,
you'll get the exact same assembler result as today. If you set the
flags on a function, then the caller will set the flags to that before
calling, but it's only necessary if they're different from the flags in
the current function.
And perhaps there should be a way to specify a function that can accept
any flag configuration. In that case, memoizing that function would
require considering the floating point flags as an extra parameter.
Now, tell me, am I using a missile to kill a fly?
--
Michel Fortin
michel.for...@michelf.com
http://michelf.com/
