Date: Wed, 2 Apr 2003 13:07:14 -0800 From: Marcel Moolenaar <marcel@xcllnt.net> To: Bruce Evans <bde@zeta.org.au> Cc: Alexander Leidinger <Alexander@Leidinger.net> Subject: Re: cvs commit: src/sys/ia64/include float.h Message-ID: <20030402210714.GB65073@dhcp01.pn.xcllnt.net> In-Reply-To: <20030402203725.O26345@gamplex.bde.org> References: <200303272038.h2RKcM7L096560@repoman.freebsd.org> <20030327204935.GA18134@HAL9000.homeunix.com> <20030330175646.281097ad.Alexander@Leidinger.net> <20030331082023.GE11307@cirb503493.alcatel.com.au> <20030401172440.701aaafd.Alexander@Leidinger.net> <20030401200457.GA30284@cirb503493.alcatel.com.au> <20030402154250.X25489@gamplex.bde.org> <20030402075905.GA30835@cirb503493.alcatel.com.au> <20030402203725.O26345@gamplex.bde.org>
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On Wed, Apr 02, 2003 at 09:19:21PM +1000, Bruce Evans wrote: > On Wed, 2 Apr 2003, Peter Jeremy wrote: > > > On Wed, Apr 02, 2003 at 04:21:30PM +1000, Bruce Evans wrote: > > >On Wed, 2 Apr 2003, Peter Jeremy wrote: > > > > > >> On Tue, Apr 01, 2003 at 05:24:40PM +0200, Alexander Leidinger wrote: > > >> >We noticed that icc does use other values for LDBL_MIN than we do, and > > >> >instead of just thinking that Intel does it right I wanted to verify it. > > > > > >This might be caused by icc actually understanding the target's default > > >precision for long doubles (FreeBSD changes the hardware default of 64-bit > > >to 53-bit for technical reasons). > > > > Is this also true on ia64? > > Probably not. ia64's _fpmath.h says that there are 64 mantissa bits, > and we don't reduce the precision AFAIK. Correct. Note that the 64-bit significand includes an explicit integer bit. The binary point is assumed to be between bits 62 and 63. Note also that the 82-bit FP registers have a 17-bit exponent to aid in near-overflow and near-underflow computations in IEEE754 double- extended format. Of course an exception is still raised if the result does not fit the target if the target is in double-extended format. -- Marcel Moolenaar USPA: A-39004 marcel@xcllnt.net
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