13a8617a8SJordan K. Hubbard /* s_logbf.c -- float version of s_logb.c. 23a8617a8SJordan K. Hubbard * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. 33a8617a8SJordan K. Hubbard */ 43a8617a8SJordan K. Hubbard 53a8617a8SJordan K. Hubbard /* 63a8617a8SJordan K. Hubbard * ==================================================== 73a8617a8SJordan K. Hubbard * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 83a8617a8SJordan K. Hubbard * 93a8617a8SJordan K. Hubbard * Developed at SunPro, a Sun Microsystems, Inc. business. 103a8617a8SJordan K. Hubbard * Permission to use, copy, modify, and distribute this 113a8617a8SJordan K. Hubbard * software is freely granted, provided that this notice 123a8617a8SJordan K. Hubbard * is preserved. 133a8617a8SJordan K. Hubbard * ==================================================== 143a8617a8SJordan K. Hubbard */ 153a8617a8SJordan K. Hubbard 163a8617a8SJordan K. Hubbard #ifndef lint 177f3dea24SPeter Wemm static char rcsid[] = "$FreeBSD$"; 183a8617a8SJordan K. Hubbard #endif 193a8617a8SJordan K. Hubbard 203a8617a8SJordan K. Hubbard #include "math.h" 213a8617a8SJordan K. Hubbard #include "math_private.h" 223a8617a8SJordan K. Hubbard 2300b1756bSBruce Evans static const float 2400b1756bSBruce Evans two25 = 3.355443200e+07; /* 0x4c000000 */ 2500b1756bSBruce Evans 2659b19ff1SAlfred Perlstein float 2759b19ff1SAlfred Perlstein logbf(float x) 283a8617a8SJordan K. Hubbard { 293a8617a8SJordan K. Hubbard int32_t ix; 303a8617a8SJordan K. Hubbard GET_FLOAT_WORD(ix,x); 313a8617a8SJordan K. Hubbard ix &= 0x7fffffff; /* high |x| */ 323a8617a8SJordan K. Hubbard if(ix==0) return (float)-1.0/fabsf(x); 333a8617a8SJordan K. Hubbard if(ix>=0x7f800000) return x*x; 3400b1756bSBruce Evans if(ix<0x00800000) { 3500b1756bSBruce Evans x *= two25; /* convert subnormal x to normal */ 3600b1756bSBruce Evans GET_FLOAT_WORD(ix,x); 3700b1756bSBruce Evans ix &= 0x7fffffff; 3800b1756bSBruce Evans return (float) ((ix>>23)-127-25); 3900b1756bSBruce Evans } else 4000b1756bSBruce Evans return (float) ((ix>>23)-127); 413a8617a8SJordan K. Hubbard } 42