| /* e_log10f.c -- float version of e_log10.c. |
| * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. |
| */ |
| |
| /* |
| * ==================================================== |
| * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
| * |
| * Developed at SunPro, a Sun Microsystems, Inc. business. |
| * Permission to use, copy, modify, and distribute this |
| * software is freely granted, provided that this notice |
| * is preserved. |
| * ==================================================== |
| */ |
| |
| #include <math.h> |
| #include <math_private.h> |
| #include <fix-int-fp-convert-zero.h> |
| |
| static const float |
| two25 = 3.3554432000e+07, /* 0x4c000000 */ |
| ivln10 = 4.3429449201e-01, /* 0x3ede5bd9 */ |
| log10_2hi = 3.0102920532e-01, /* 0x3e9a2080 */ |
| log10_2lo = 7.9034151668e-07; /* 0x355427db */ |
| |
| float |
| __ieee754_log10f(float x) |
| { |
| float y,z; |
| int32_t i,k,hx; |
| |
| GET_FLOAT_WORD(hx,x); |
| |
| k=0; |
| if (hx < 0x00800000) { /* x < 2**-126 */ |
| if (__builtin_expect((hx&0x7fffffff)==0, 0)) |
| return -two25/fabsf (x); /* log(+-0)=-inf */ |
| if (__builtin_expect(hx<0, 0)) |
| return (x-x)/(x-x); /* log(-#) = NaN */ |
| k -= 25; x *= two25; /* subnormal number, scale up x */ |
| GET_FLOAT_WORD(hx,x); |
| } |
| if (__builtin_expect(hx >= 0x7f800000, 0)) return x+x; |
| k += (hx>>23)-127; |
| i = ((uint32_t)k&0x80000000)>>31; |
| hx = (hx&0x007fffff)|((0x7f-i)<<23); |
| y = (float)(k+i); |
| if (FIX_INT_FP_CONVERT_ZERO && y == 0.0f) |
| y = 0.0f; |
| SET_FLOAT_WORD(x,hx); |
| z = y*log10_2lo + ivln10*__ieee754_logf(x); |
| return z+y*log10_2hi; |
| } |
| strong_alias (__ieee754_log10f, __log10f_finite) |
