1/* e_log10f.c -- float version of e_log10.c. 2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. 3 */ 4
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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>
| 1/* 2 * ==================================================== 3 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 4 * 5 * Developed at SunPro, a Sun Microsystems, Inc. business. 6 * Permission to use, copy, modify, and distribute this 7 * software is freely granted, provided that this notice 8 * is preserved. 9 * ==================================================== 10 */ 11 12#include <sys/cdefs.h>
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17__FBSDID("$FreeBSD: head/lib/msun/src/e_log10f.c 176451 2008-02-22 02:30:36Z das $");
| 13__FBSDID("$FreeBSD: head/lib/msun/src/e_log2f.c 216211 2010-12-05 22:11:22Z das $");
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18 19#include "math.h" 20#include "math_private.h"
| 14 15#include "math.h" 16#include "math_private.h"
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| 17#include "k_logf.h"
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21 22static const float 23two25 = 3.3554432000e+07, /* 0x4c000000 */
| 18 19static const float 20two25 = 3.3554432000e+07, /* 0x4c000000 */
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24ivln10 = 4.3429449201e-01, /* 0x3ede5bd9 */ 25log10_2hi = 3.0102920532e-01, /* 0x3e9a2080 */ 26log10_2lo = 7.9034151668e-07; /* 0x355427db */
| 21ivln2hi = 0x1.716p+0f, 22ivln2lo = -0x1.7135a8fa03d11p-13;
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27 28static const float zero = 0.0; 29 30float
| 23 24static const float zero = 0.0; 25 26float
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31__ieee754_log10f(float x)
| 27__ieee754_log2f(float x)
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32{
| 28{
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33 float y,z;
| 29 float f,hi,lo;
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34 int32_t i,k,hx; 35 36 GET_FLOAT_WORD(hx,x); 37 38 k=0; 39 if (hx < 0x00800000) { /* x < 2**-126 */ 40 if ((hx&0x7fffffff)==0) 41 return -two25/zero; /* log(+-0)=-inf */ 42 if (hx<0) return (x-x)/zero; /* log(-#) = NaN */ 43 k -= 25; x *= two25; /* subnormal number, scale up x */ 44 GET_FLOAT_WORD(hx,x); 45 } 46 if (hx >= 0x7f800000) return x+x; 47 k += (hx>>23)-127;
| 30 int32_t i,k,hx; 31 32 GET_FLOAT_WORD(hx,x); 33 34 k=0; 35 if (hx < 0x00800000) { /* x < 2**-126 */ 36 if ((hx&0x7fffffff)==0) 37 return -two25/zero; /* log(+-0)=-inf */ 38 if (hx<0) return (x-x)/zero; /* log(-#) = NaN */ 39 k -= 25; x *= two25; /* subnormal number, scale up x */ 40 GET_FLOAT_WORD(hx,x); 41 } 42 if (hx >= 0x7f800000) return x+x; 43 k += (hx>>23)-127;
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48 i = ((u_int32_t)k&0x80000000)>>31; 49 hx = (hx&0x007fffff)|((0x7f-i)<<23); 50 y = (float)(k+i); 51 SET_FLOAT_WORD(x,hx); 52 z = y*log10_2lo + ivln10*__ieee754_logf(x); 53 return z+y*log10_2hi;
| 44 hx &= 0x007fffff; 45 i = (hx+(0x4afb0d))&0x800000; 46 SET_FLOAT_WORD(x,hx|(i^0x3f800000)); /* normalize x or x/2 */ 47 k += (i>>23); 48 f = __kernel_logf(x); 49 x = x - 1; 50 GET_FLOAT_WORD(hx,x); 51 SET_FLOAT_WORD(hi,hx&0xfffff000); 52 lo = x - hi; 53 return (x+f)*ivln2lo + (lo+f)*ivln2hi + hi*ivln2hi + k;
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54}
| 54}
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