Date: Fri, 21 Oct 2011 06:26:07 +0000 (UTC) From: David Schultz <das@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r226595 - head/lib/msun/src Message-ID: <201110210626.p9L6Q7oB009653@svn.freebsd.org>
next in thread | raw e-mail | index | archive | help
Author: das Date: Fri Oct 21 06:26:07 2011 New Revision: 226595 URL: http://svn.freebsd.org/changeset/base/226595 Log: Per IEEE754r, pow(1, y) is 1 even if y is NaN, and pow(-1, +-Inf) is 1. MFC after: 2 weeks Modified: head/lib/msun/src/e_pow.c head/lib/msun/src/e_powf.c Modified: head/lib/msun/src/e_pow.c ============================================================================== --- head/lib/msun/src/e_pow.c Fri Oct 21 06:25:31 2011 (r226594) +++ head/lib/msun/src/e_pow.c Fri Oct 21 06:26:07 2011 (r226595) @@ -109,6 +109,9 @@ __ieee754_pow(double x, double y) /* y==zero: x**0 = 1 */ if((iy|ly)==0) return one; + /* x==1: 1**y = 1, even if y is NaN */ + if (hx==0x3ff00000 && lx == 0) return one; + /* y!=zero: result is NaN if either arg is NaN */ if(ix > 0x7ff00000 || ((ix==0x7ff00000)&&(lx!=0)) || iy > 0x7ff00000 || ((iy==0x7ff00000)&&(ly!=0))) @@ -138,7 +141,7 @@ __ieee754_pow(double x, double y) if(ly==0) { if (iy==0x7ff00000) { /* y is +-inf */ if(((ix-0x3ff00000)|lx)==0) - return y - y; /* inf**+-1 is NaN */ + return one; /* (-1)**+-inf is NaN */ else if (ix >= 0x3ff00000)/* (|x|>1)**+-inf = inf,0 */ return (hy>=0)? y: zero; else /* (|x|<1)**-,+inf = inf,0 */ Modified: head/lib/msun/src/e_powf.c ============================================================================== --- head/lib/msun/src/e_powf.c Fri Oct 21 06:25:31 2011 (r226594) +++ head/lib/msun/src/e_powf.c Fri Oct 21 06:26:07 2011 (r226595) @@ -67,6 +67,9 @@ __ieee754_powf(float x, float y) /* y==zero: x**0 = 1 */ if(iy==0) return one; + /* x==1: 1**y = 1, even if y is NaN */ + if (hx==0x3f800000) return one; + /* y!=zero: result is NaN if either arg is NaN */ if(ix > 0x7f800000 || iy > 0x7f800000) @@ -90,7 +93,7 @@ __ieee754_powf(float x, float y) /* special value of y */ if (iy==0x7f800000) { /* y is +-inf */ if (ix==0x3f800000) - return y - y; /* inf**+-1 is NaN */ + return one; /* (-1)**+-inf is NaN */ else if (ix > 0x3f800000)/* (|x|>1)**+-inf = inf,0 */ return (hy>=0)? y: zero; else /* (|x|<1)**-,+inf = inf,0 */
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201110210626.p9L6Q7oB009653>