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 <sys/cdefs.h> 17 #include <limits.h> 18 19 #include "math.h" 20 #include "math_private.h" 21 22 int ilogbf(float x) 23 { 24 int32_t hx,ix; 25 26 GET_FLOAT_WORD(hx,x); 27 hx &= 0x7fffffff; 28 if(hx<0x00800000) { 29 if(hx==0) 30 return FP_ILOGB0; 31 else /* subnormal x */ 32 for (ix = -126,hx<<=8; hx>0; hx<<=1) ix -=1; 33 return ix; 34 } 35 else if (hx<0x7f800000) return (hx>>23)-127; 36 else if (hx>0x7f800000) return FP_ILOGBNAN; 37 else return INT_MAX; 38 } 39