1 /* s_ilogbf.c -- float version of s_ilogb.c. 2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. 3 */ 4 5 /* 6 * ==================================================== 7 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 8 * 9 * Developed at SunPro, a Sun Microsystems, Inc. business. 10 * Permission to use, copy, modify, and distribute this 11 * software is freely granted, provided that this notice 12 * is preserved. 13 * ==================================================== 14 */ 15 16 #include "cdefs-compat.h" 17 //__FBSDID("$FreeBSD: src/lib/msun/src/s_ilogbf.c,v 1.8 2008/02/22 02:30:35 das Exp $"); 18 19 #include <limits.h> 20 21 #include "openlibm.h" 22 #include "math_private.h" 23 24 int ilogbf(float x) 25 { 26 int32_t hx,ix; 27 28 GET_FLOAT_WORD(hx,x); 29 hx &= 0x7fffffff; 30 if(hx<0x00800000) { 31 if(hx==0) 32 return FP_ILOGB0; 33 else /* subnormal x */ 34 for (ix = -126,hx<<=8; hx>0; hx<<=1) ix -=1; 35 return ix; 36 } 37 else if (hx<0x7f800000) return (hx>>23)-127; 38 else if (hx>0x7f800000) return FP_ILOGBNAN; 39 else return INT_MAX; 40 } 41