1 /* s_logbf.c -- float version of s_logb.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 #ifndef lint 17 static char rcsid[] = "$FreeBSD$"; 18 #endif 19 20 #include "math.h" 21 #include "math_private.h" 22 23 float 24 logbf(float x) 25 { 26 int32_t ix; 27 GET_FLOAT_WORD(ix,x); 28 ix &= 0x7fffffff; /* high |x| */ 29 if(ix==0) return (float)-1.0/fabsf(x); 30 if(ix>=0x7f800000) return x*x; 31 if((ix>>=23)==0) /* IEEE 754 logb */ 32 return -126.0; 33 else 34 return (float) (ix-127); 35 } 36