From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Buettner To: Andrew Cagney , Kevin Buettner Cc: Mark Kettenis , gdb-patches@sources.redhat.com Subject: Re: [rfc] Add some more floatformat types .... Date: Fri, 17 Aug 2001 11:12:00 -0000 Message-id: <1010817181153.ZM4294@ocotillo.lan> References: <3B76164B.9060908@cygnus.com> <3B7C1287.9080906@cygnus.com> <3B7C8AFA.1080504@cygnus.com> <200108171308.f7HD8Q325622@delius.kettenis.local> <3B7D4280.8010005@cygnus.com> <1010817163956.ZM4083@ocotillo.lan> <3B7D507D.4010801@cygnus.com> X-SW-Source: 2001-08/msg00208.html On Aug 17, 1:12pm, Andrew Cagney wrote: > > The fly in the ointment is that the IA-64 also has a quad precision > > real type whose width is 128 bits (1 bit sign, 15 bit exponent, > > 112 bit significand). > > Ulgh! So we now need two IA-64 floating point types, any suggestion for > a name? Does: > > ia64_ext > ia64_quad > > look ok (and please no one look at the VAX :-). Well, actually, there are a total of seven data types that the IA-64 supports. (However, two of them are integer types.) From section 5.1 of the Intel IA-64 Architecture Software Developer's Manual; Volume 1: IA-64 Application Architecture: Six data types are supported directly: single, double, double-extended real (IEEE real types); 64-bit signed integer, 64-bit unsigned integer, and the 82-bit floating point register format. A "Parallel FP" format where a pair of IEEE single precision values occupy a floating point registers significand is also supported. A seventh data type, IEEE-style quad-precision, is supported in software routines. A future architecture extension may include additional support for the quad-precision real type. Anyway, my objection to using ``ia64_ext'' for the 82-bit register type stems from the fact that this name would probably be more appropriate for the 80-bit double-extended type. Especially since this is the convention already used for x86. How 'bout this instead? ia64_ext - 80-bit double-extended ia64_reg - 82-bit fp register ia64_quad - 128-bit quad-precision Online documentation on the IA-64 floating point formats may be found at: http://devresource.hp.com/devresource/Docs/Refs/IA64ISA/fp_program4.html Roughly the same material may also be found in chapter 5 of the following PDF file: ftp://download.intel.com/design/IA-64/Downloads/24531702s.pdf Kevin