----Original Message----
>From: Richard Earnshaw
>Sent: 15 April 2005 18:08
>> In any case, the ARM or Alpha isn't prevented from working in such a
>> fashion just because the rounding mode is encoded in the instruction; it
>> just means that fp primitives have to be compiled as intrinsics that test
>> whatever flag controls the rounding mode and then branch to an fp insn of
>> the appropriate form.
> Code that changes the rounding has to be wrapped with certain pragmas to
> inform the compiler that this might happen: on something like ARM+FPA
> that might permit dynamic code switching, but I doubt anyone would
> really want to pay that price.
It's a very arch-dependent price, though. On an arch where you have
conditional execution per-instruction, it could be a very low overhead
indeed.
cheers,
DaveK
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Can't think of a witty .sigline today....
