------- Comment #8 from gdr at cs dot tamu dot edu 2006-05-23 21:58 ------- Subject: Re: __builtin_nanf("") doesn't return a _quiet_ nan on parisc
"dave at hiauly1 dot hia dot nrc dot ca" <[EMAIL PROTECTED]> writes: | ------- Comment #7 from dave at hiauly1 dot hia dot nrc dot ca 2006-05-23 16:28 ------- | Subject: Re: __builtin_nanf("") doesn't return a _quiet_ nan on parisc | | > ------- Comment #6 from rth at gcc dot gnu dot org 2006-05-23 15:00 ------- | > (In reply to comment #4) | > > This isn't a target bug as far as I can tell. The value generated | > > by __builtin_nanf("") as shown by Nan2.c is 0x7fc00000. The same | > > value is printed on x86. This is a signaling NaN. Positive quiet | > > NaNs range between 0x7f800001 and 0x7fbfffff. | > | > Incorrect. The canonical QNaN on x86 (and most other targets) is | > 0x7fc00000. It would seem that PA has the same reversed quiet bit | > as MIPS. See real_format->qnan_msb_set and mips_ieee_single. | | Interesting. The HP architecture docments for PA 1.1 and 2.0 | state that PA-RISC fully conforms to ANSI/IEEE Std 754-1985, so | I presume that this isn't specified (don't have a copy of the | spec handy), so there's no actual canonical format. I see this | was something of a point of contention in 754R meetings. The IEEE--754 specification is a *conceptual model*, not a "physical" wired format. As long as the units behave functionally as required, it should be fine. -- Gaby -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27627