From 8b1fadd6a89f12cbc81c5d621a75b91dd9eedec2 Mon Sep 17 00:00:00 2001 From: Pixel Date: Sat, 5 Feb 2011 11:06:07 -0800 Subject: Adding Sun's fdlibm, and libnix's scanf, tweaked to become an xscanf. Adding a few more libc inlined also. --- libm/src/s_ilogb.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) create mode 100644 libm/src/s_ilogb.c (limited to 'libm/src/s_ilogb.c') diff --git a/libm/src/s_ilogb.c b/libm/src/s_ilogb.c new file mode 100644 index 0000000..ae9404e --- /dev/null +++ b/libm/src/s_ilogb.c @@ -0,0 +1,46 @@ + +/* @(#)s_ilogb.c 1.3 95/01/18 */ +/* + * ==================================================== + * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. + * + * Developed at SunSoft, a Sun Microsystems, Inc. business. + * Permission to use, copy, modify, and distribute this + * software is freely granted, provided that this notice + * is preserved. + * ==================================================== + */ + +/* ilogb(double x) + * return the binary exponent of non-zero x + * ilogb(0) = 0x80000001 + * ilogb(inf/NaN) = 0x7fffffff (no signal is raised) + */ + +#include "fdlibm.h" + +#ifdef __STDC__ + int ilogb(double x) +#else + int ilogb(x) + double x; +#endif +{ + int hx,lx,ix; + + hx = (__HI(x))&0x7fffffff; /* high word of x */ + if(hx<0x00100000) { + lx = __LO(x); + if((hx|lx)==0) + return 0x80000001; /* ilogb(0) = 0x80000001 */ + else /* subnormal x */ + if(hx==0) { + for (ix = -1043; lx>0; lx<<=1) ix -=1; + } else { + for (ix = -1022,hx<<=11; hx>0; hx<<=1) ix -=1; + } + return ix; + } + else if (hx<0x7ff00000) return (hx>>20)-1023; + else return 0x7fffffff; +} -- cgit v1.2.3