From mboxrd@z Thu Jan  1 00:00:00 1970
From: craig@jcb-sc.com
To: ross.s@ihug.co.nz
Cc: craig@jcb-sc.com
Subject: Re: Rounding errors using doubles?
Date: Fri, 19 Mar 1999 06:36:00 -0000
Message-id: <19990319142042.16973.qmail@deer>
In-reply-to: < 002d01be71aa$30d420e0$a8a11dcb@animal.ihug.co.nz >(ross.s@ihug.co.nz)
References: <002d01be71aa$30d420e0$a8a11dcb@animal.ihug.co.nz> <002d01be71aa$30d420e0$a8a11dcb@animal.ihug.co.nz>
X-SW-Source: 1999-03/msg00649.html

>Both compilers have options to force pure 64-bit arithmetic (53-bit
>precision) throughout (at some cost in speed): -ffloat-store on EGCS,
>/Op on MSVC.

Take -ffloat-store off that list: it doesn't do the above.  It affects
only explicit *stores* to *variables*, not intermediate coputations.  egcs
provides no way to force 64-bit FP arithmetic.  In fact, I'd be surprised
if -ffloat-store "improved" the behavior of the (buggy) program originally
submitted in this thread.

Other than that, thanks for the decent explanation -- if this isn't
in the FAQ, it should be, and if it is, we should refrain from
repeating it, and point people there instead!

        tq vm, (burley)

From mboxrd@z Thu Jan  1 00:00:00 1970
From: craig@jcb-sc.com
To: ross.s@ihug.co.nz
Cc: craig@jcb-sc.com
Subject: Re: Rounding errors using doubles?
Date: Wed, 31 Mar 1999 23:46:00 -0000
Message-ID: <19990319142042.16973.qmail@deer>
References: <002d01be71aa$30d420e0$a8a11dcb@animal.ihug.co.nz>
X-SW-Source: 1999-03n/msg00654.html
Message-ID: <19990331234600._k-Wdztglk6BmaWYxLTi5cAjufH2IWinSMTL6urzI8Y@z>

>Both compilers have options to force pure 64-bit arithmetic (53-bit
>precision) throughout (at some cost in speed): -ffloat-store on EGCS,
>/Op on MSVC.

Take -ffloat-store off that list: it doesn't do the above.  It affects
only explicit *stores* to *variables*, not intermediate coputations.  egcs
provides no way to force 64-bit FP arithmetic.  In fact, I'd be surprised
if -ffloat-store "improved" the behavior of the (buggy) program originally
submitted in this thread.

Other than that, thanks for the decent explanation -- if this isn't
in the FAQ, it should be, and if it is, we should refrain from
repeating it, and point people there instead!

        tq vm, (burley)