... a value in the second operand [source] is an SNaN, that SNaN is forwarded unchaged to the destination (that is, a QNaN version of the SNaN is not returned). If only one value is a NaN (SNaN or QNaN) for this instruction, the second operand (source operand), either a NaN or a valid floating-point value, is written to the...

... a value in the second operand [source] is an SNaN, that SNaN is forwarded unchaged to the destination (that is, a QNaN version of the SNaN is not returned). If only one value is a NaN (SNaN or QNaN) for this instruction, the second operand (source operand), either a NaN or a valid floating-point value, is written to ...

...Value = REAL(Z'FFFFFFFF') RETURN END With the assumption of IEEE standard floating point those should work. (I am not so sure what happens with BOZ constants on machines with a different bit order for integer and floating point data.) Others have indicated ways to generate qNaN with constant expressions. I don't know if you can generate sNaN that way. -- glen

...? As I recall, yes. There's also a plan to eventually allow initializing real variables to snan or qnan, but I don't think that's going to make it in for 4.3. It allows other values including qNaN, but unfortunately not yet sNaN. Available options: -finit-local-zero -finit-integer=n -finit-real=<zero|inf|-inf|nan>...

...s included in the source tree yet. Does it allow one to initialize to other than zero? As I recall, yes. There's also a plan to eventually allow initializing real variables to snan or qnan, but I don't think that's going to make it in for 4.3. To make it easier to find (otherwise) uninitialized variables it is convenient to initialize them to an unlikely value. One ...

... software to create/insert NaNs, whether sNaN or qNAN. And furthermore (§4.8.3.6): ------quote ...7. When an SNaN is converted to a QNaN, the conversion is handled by setting the most...an SNaN source operand converted to a QNaN or the QNaN floating- point indefinite value. ------endquote...floating-point invalid-operation, even in case of QNaN, if I understand correctly, was indeed required to...

On 2/20/07, erik quanstrom <quanstro@coraid.com> wrote: after a bit of actual thought, i think that NaN is supposed to generate a note. if you do catch the note, the program should work fine. This is distinct from sNaN/qNaN, right? --Joel

... default) for "missing" would have been quite valuable. I'm just afraid of bringing it up so late in the game... Interestingly IBM's "High Level Assembler" does support defining two kinds of quiet NaN in floating-point constants: (NAN) implies machine default (double 0x7ff80000...) and (QNAN) implies 0x7ffc0000... but I don't know of any software that exploits this. Michel.

... to this thread, but if I may be |> indulged a little, what is wrong with... |> |> max(QNaN,0) = 0 |> max(SNaN,0) = SNaN BAD idea. Sorry. Firstly, IEEE 754 requires max(SNaN,0) to raise the invalid exception, secondly, that would imply that QNaN+0.0 = 0.0 and, thirdly, the only languages that 'support' IEEE 754 use only QNaNs. Regards, Nick Maclaren.

... Nick's point, the problem is the conflation of two meanings for NaN, so it wouldn't be at all surprising to me if there were *no* definite right answer for max(NaN,0). Now, I probably have less experience and knowledge in this area than anyone who has so far contributed to this thread, but if I may be indulged a little, what is wrong with... max(QNaN,0) = 0 max(SNaN,0) = SNaN