Date: Thu, 31 Oct 2002 20:28:33 +1100 (EST) From: Bruce Evans <bde@zeta.org.au> To: "M. Warner Losh" <imp@bsdimp.com> Cc: tlambert2@mindspring.com, <rittle@labs.mot.com>, <rittle@latour.rsch.comm.mot.com>, <current@FreeBSD.ORG>, <dschultz@uclink.Berkeley.EDU> Subject: Re: Lack of real long double support Message-ID: <20021031202343.W8632-100000@gamplex.bde.org> In-Reply-To: <20021030.170154.35505346.imp@bsdimp.com>
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On Wed, 30 Oct 2002, M. Warner Losh wrote: > The one issue that I've seen is > > long double a = 1.0L; > long double b = 1.0L + LDBL_EPSION > if (a == b) abort(); > > which is what I'm trying to fix. (note, "1.0L" must be spelled > "oneld()" and long double oneld() { return (1.0L);}) to avoid the > optimizer getting it right. Example of how fixing this breaks a similar assertion for DBL_ESPILON: %%% $ cat z.c #include <float.h> #include <floatingpoint.h> long double oneld = 1.0L; double oned = 1.0; int main() { test(2); test(3); } int test(int prec) { long double la, lb; double a, b; fpsetprec(prec); la = oneld; lb = oneld + LDBL_EPSILON; if (la == lb) printf("LDBL_EPSILON failed test 1 with prec %d\n", prec); la = oneld; lb = oneld + LDBL_EPSILON / 2; if (la != lb) printf("LDBL_EPSILON failed test 2 with prec %d\n", prec); a = oned; b = oned + DBL_EPSILON; if (a == b) printf("DBL_EPSILON failed test 1 with prec %d\n", prec); a = oned; b = oned + DBL_EPSILON / 2; if (a != b) printf("DBL_EPSILON failed test 2 with prec %d\n", prec); } $ cc -o z z.c $ ./z LDBL_EPSILON failed test 1 with prec 2 $ cc -O -o z z.c. $ ./z LDBL_EPSILON failed test 1 with prec 2 DBL_EPSILON failed test 2 with prec 3 %%% The full brokenness only shows up with -O. Bruce To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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