On Sat, 18 Jun 2005, Robert Dewar wrote:
Mattias Karlsson wrote:
On Sat, 18 Jun 2005, Robert Dewar wrote:
Mattias Karlsson wrote:
Don't know about you, but I consider any processor that is unable to
store a register to memory and then read back the same value to be buggy.
THe x86/x87 does not violate this requirement
In my Obi-Wan-Point-Of-View it does. :-)
Well I think it is inapprorpiate to assign erroneous points of
view to Obi-Wan :-) Once again, on the x86/x87 the process IS "able
to store a register to memory and then read back the same value".
ANy claim to the contrary is ill-informed.
This entire debate comes from one thing: currently floating point has
always type long double untill stored to memory, regardless of
user-specified type. At -O1 this becomes more or less non-deterministic.
Yes, right, but that is a different issue from being able to store
a register to memory and then read back the same value.
I confess of being overly generic, and quite fuzzy about my point.
Anyway my point of view is that the solution to anyone needing strict IEEE
semantics are:
1) Use -float-store
2) Use sse math
3) Learn to live without it.
Since the "gcc-is-buggy" solution of changing x87 rounding modes will:
1) Be a lot of work.
2) Cause a lot of regressions.
