fixed more binutils issues (newer gcc/libc)
[zpugcc/jano.git] / toolchain / gcc / newlib / libm / common / sf_log1p.c
blobe09170f3e6f274ec2f711b7fccaa6606fd5bf40e
1 /* sf_log1p.c -- float version of s_log1p.c.
2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3 */
5 /*
6 * ====================================================
7 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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 * ====================================================
16 #include "fdlibm.h"
18 #ifdef __STDC__
19 static const float
20 #else
21 static float
22 #endif
23 ln2_hi = 6.9313812256e-01, /* 0x3f317180 */
24 ln2_lo = 9.0580006145e-06, /* 0x3717f7d1 */
25 two25 = 3.355443200e+07, /* 0x4c000000 */
26 Lp1 = 6.6666668653e-01, /* 3F2AAAAB */
27 Lp2 = 4.0000000596e-01, /* 3ECCCCCD */
28 Lp3 = 2.8571429849e-01, /* 3E924925 */
29 Lp4 = 2.2222198546e-01, /* 3E638E29 */
30 Lp5 = 1.8183572590e-01, /* 3E3A3325 */
31 Lp6 = 1.5313838422e-01, /* 3E1CD04F */
32 Lp7 = 1.4798198640e-01; /* 3E178897 */
34 #ifdef __STDC__
35 static const float zero = 0.0;
36 #else
37 static float zero = 0.0;
38 #endif
40 #ifdef __STDC__
41 float log1pf(float x)
42 #else
43 float log1pf(x)
44 float x;
45 #endif
47 float hfsq,f,c,s,z,R,u;
48 __int32_t k,hx,hu,ax;
50 GET_FLOAT_WORD(hx,x);
51 ax = hx&0x7fffffff;
53 k = 1;
54 if (!FLT_UWORD_IS_FINITE(hx)) return x+x;
55 if (hx < 0x3ed413d7) { /* x < 0.41422 */
56 if(ax>=0x3f800000) { /* x <= -1.0 */
57 if(x==(float)-1.0) return -two25/zero; /* log1p(-1)=+inf */
58 else return (x-x)/(x-x); /* log1p(x<-1)=NaN */
60 if(ax<0x31000000) { /* |x| < 2**-29 */
61 if(two25+x>zero /* raise inexact */
62 &&ax<0x24800000) /* |x| < 2**-54 */
63 return x;
64 else
65 return x - x*x*(float)0.5;
67 if(hx>0||hx<=((__int32_t)0xbe95f61f)) {
68 k=0;f=x;hu=1;} /* -0.2929<x<0.41422 */
70 if(k!=0) {
71 if(hx<0x5a000000) {
72 u = (float)1.0+x;
73 GET_FLOAT_WORD(hu,u);
74 k = (hu>>23)-127;
75 /* correction term */
76 c = (k>0)? (float)1.0-(u-x):x-(u-(float)1.0);
77 c /= u;
78 } else {
79 u = x;
80 GET_FLOAT_WORD(hu,u);
81 k = (hu>>23)-127;
82 c = 0;
84 hu &= 0x007fffff;
85 if(hu<0x3504f7) {
86 SET_FLOAT_WORD(u,hu|0x3f800000);/* normalize u */
87 } else {
88 k += 1;
89 SET_FLOAT_WORD(u,hu|0x3f000000); /* normalize u/2 */
90 hu = (0x00800000-hu)>>2;
92 f = u-(float)1.0;
94 hfsq=(float)0.5*f*f;
95 if(hu==0) { /* |f| < 2**-20 */
96 if(f==zero) { if(k==0) return zero;
97 else {c += k*ln2_lo; return k*ln2_hi+c;}}
98 R = hfsq*((float)1.0-(float)0.66666666666666666*f);
99 if(k==0) return f-R; else
100 return k*ln2_hi-((R-(k*ln2_lo+c))-f);
102 s = f/((float)2.0+f);
103 z = s*s;
104 R = z*(Lp1+z*(Lp2+z*(Lp3+z*(Lp4+z*(Lp5+z*(Lp6+z*Lp7))))));
105 if(k==0) return f-(hfsq-s*(hfsq+R)); else
106 return k*ln2_hi-((hfsq-(s*(hfsq+R)+(k*ln2_lo+c)))-f);
109 #ifdef _DOUBLE_IS_32BITS
111 #ifdef __STDC__
112 double log1p(double x)
113 #else
114 double log1p(x)
115 double x;
116 #endif
118 return (double) log1pf((float) x);
121 #endif /* defined(_DOUBLE_IS_32BITS) */