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RE: Processor-specific code
>>>>> "Dave" == Dave Korn <dave.korn@artimi.com> writes:
Dave> ----Original Message----
>> From: Paul Koning Sent: 15 April 2005 17:56
>>>>>>> "Dave" == Dave Korn <dave.korn@artimi.com> writes:
>>
Dave> Doesn't the C language spec require the mode to be switchable
Dave> at runtime?
>>
Dave> In any case, the ARM or Alpha isn't prevented from working in
Dave> such a fashion just because the rounding mode is encoded in the
Dave> instruction; it just means that fp primitives have to be
Dave> compiled as intrinsics that test whatever flag controls the
Dave> rounding mode and then branch to an fp insn of the appropriate
Dave> form.
>> That only works if the notion of switchable rounding mode exists.
Dave> I'm not sure. Either you don't get me, or I don't get you, but
Dave> what I thought I was describing was a way of working around the
Dave> lack of a switchable mode by compiling the code both ways with
Dave> a runtime test of a flag.
Sorry, poor wording.
What I meant is that those architectures do floating point in exactly
one way. You have NO way to say what kind of rounding you want, not
by a settable state, not by a different opcode -- not at all.
paul