* The new 128-bit floating point _Float128 per ISO/IEC/IEEE 60559:2011 ?? [not found] <CAH6eHdRFiHHNfHEWcPF+6ZgthGfPLWz3T7Qetz6hcjFySWQGEA@mail.gmail.com> @ 2018-03-13 2:47 ` Dennis Clarke 2018-03-13 12:04 ` Jonathan Wakely 0 siblings, 1 reply; 3+ messages in thread From: Dennis Clarke @ 2018-03-13 2:47 UTC (permalink / raw) To: gcc-help I did some digging and found that the new floating point types[1] really only exist in a few architectures. Near as I can tell. However I have yet to see them. Yet. Working on it. I am not sure if the Debian packages for gcc allow them nor sure if the kernel config even has the options yet. Certianly math emulation can be done but actual software implementations of _Float128? I don't *yet* know. I have linux kernel 4.15.9 on ppc64 however that won't suffice. Certainly won't work on plain jane 32-bit x86 either regardless of kernel rev. Has anyone seen these in the wild? Dennis [1] per https://sourceware.org/bugzilla/show_bug.cgi?id=21539 * On ia64, powerpc64le, x86-32, and x86-64, the math library now implements 128-bit floating point as defined by ISO/IEC/IEEE 60559:2011 (IEEE 754-2008) and ISO/IEC TS 18661-3:2015. Contributed by Paul E. Murphy, Gabriel F. T. Gomes, Tulio Magno Quites Machado Filho, and Joseph Myers. To compile programs that use this feature, the compiler must support 128-bit floating point with the type name _Float128 (as defined by TS 18661-3) or __float128 (the nonstandard name used by GCC for C++, and for C prior to version 7). _GNU_SOURCE or __STDC_WANT_IEC_60559_TYPES_EXT__ must be defined to make the new interfaces visible. The new functions and macros correspond to those present for other floating-point types (except for a few obsolescent interfaces not supported for the new type), with F128 or f128 suffixes; for example, strtof128, HUGE_VAL_F128 and cosf128. Following TS 18661-3, there are no printf or scanf formats for the new type; the strfromf128 and strtof128 interfaces should be used instead. Also from earlier .... -------- Forwarded Message -------- Subject: Re: documentation error on https://gcc.gnu.org/onlinedocs/gcc-7.3.0/gcc/x86-Options.html Date: Mon, 12 Mar 2018 22:33:06 +0000 From: Jonathan Wakely <jwakely.gcc@gmail.com> To: Dennis Clarke <dclarke@blastwave.org> CC: GCC help <gcc-help@gcc.gnu.org> <snip> > gcc: error: unrecognized command line option '-mno-clfushopt'; did you > mean '-mno-clflushopt'? > > > yep .. I did. > > > Just a spelling error there for "-mclfushopt". Fixed on trunk with https://gcc.gnu.org/ml/gcc-patches/2018-03/msg00554.html > <snip> > > deb_i586$ ./sinl > Our pi constant was > 3.1415926535897932384626433832795028841971693993751L > > ---------+---------+---------+---------+---------+ > sizeof(long double) = 16 > pi may be +0.00000000000000000000000000000000000000 > sinl(pi) may be +nan > approx_pi = +nan > ld_error = -0.00000000000000000000000000000000000000 > . > . > . > > .. as well as a truely awesome mess of digits and just really borked > up results if I try anything else "fancy" like sinl(). Not surprised. I'm not sure, but I think you need a libc that is also built with -mlong-double-128, otherwise its printf doesn't know you're passing it 128-bit types. ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: The new 128-bit floating point _Float128 per ISO/IEC/IEEE 60559:2011 ?? 2018-03-13 2:47 ` The new 128-bit floating point _Float128 per ISO/IEC/IEEE 60559:2011 ?? Dennis Clarke @ 2018-03-13 12:04 ` Jonathan Wakely 2018-03-13 12:38 ` Dennis Clarke 0 siblings, 1 reply; 3+ messages in thread From: Jonathan Wakely @ 2018-03-13 12:04 UTC (permalink / raw) To: Dennis Clarke; +Cc: gcc-help On 13 March 2018 at 02:47, Dennis Clarke wrote: > > > I did some digging and found that the new floating point types[1] really > only exist in a few architectures. Near as I can tell. However I have > yet to see them. Yet. Working on it. I am not sure if the Debian > packages for gcc allow them nor sure if the kernel config even has the > options yet. Certianly math emulation can be done but actual software > implementations of _Float128? I don't *yet* know. I have linux kernel > 4.15.9 on ppc64 however that won't suffice. Certainly won't work on > plain jane 32-bit x86 either regardless of kernel rev. The kernel has nothing to do with it, does it? The requirements are on GCC and glibc. ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: The new 128-bit floating point _Float128 per ISO/IEC/IEEE 60559:2011 ?? 2018-03-13 12:04 ` Jonathan Wakely @ 2018-03-13 12:38 ` Dennis Clarke 0 siblings, 0 replies; 3+ messages in thread From: Dennis Clarke @ 2018-03-13 12:38 UTC (permalink / raw) To: gcc-help On 13/03/18 08:04 AM, Jonathan Wakely wrote: > On 13 March 2018 at 02:47, Dennis Clarke wrote: >> >> >> I did some digging and found that the new floating point types[1] really >> only exist in a few architectures. Near as I can tell. However I have >> yet to see them. Yet. Working on it. I am not sure if the Debian >> packages for gcc allow them nor sure if the kernel config even has the >> options yet. Certianly math emulation can be done but actual software >> implementations of _Float128? I don't *yet* know. I have linux kernel >> 4.15.9 on ppc64 however that won't suffice. Certainly won't work on >> plain jane 32-bit x86 either regardless of kernel rev. > > The kernel has nothing to do with it, does it? The requirements are on > GCC and glibc. > yep https://gcc.gnu.org/ml/gcc-help/2018-03/msg00036.html I have been digging around in this for months and on various platforms for a while. Have not seen things working .. yet. Real soon now. :-) The folks at Oracle state that Oracle Studio 12.6 has full support for just about everything you would want but then again, where? Oh yeah, on Solaris and even then .. maybe. I don't know yet as I have seen some breakage down in the bits there too. Anyways ... it really is great to see what recent gcc and glibc "can" do where I have been following : See GNU libc release message for 2.26 : https://sourceware.org/ml/libc-alpha/2017-08/msg00010.html See GNU libc release message for 2.27 : https://sourceware.org/ml/libc-alpha/2018-02/msg00054.html Dennis ps: catching floating point exceptions is a whole other can o worms ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2018-03-13 12:38 UTC | newest] Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- [not found] <CAH6eHdRFiHHNfHEWcPF+6ZgthGfPLWz3T7Qetz6hcjFySWQGEA@mail.gmail.com> 2018-03-13 2:47 ` The new 128-bit floating point _Float128 per ISO/IEC/IEEE 60559:2011 ?? Dennis Clarke 2018-03-13 12:04 ` Jonathan Wakely 2018-03-13 12:38 ` Dennis Clarke
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