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s_expm1f.c (176082) s_expm1f.c (176132)
1/* s_expm1f.c -- float version of s_expm1.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#include <sys/cdefs.h>
1/* s_expm1f.c -- float version of s_expm1.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#include <sys/cdefs.h>
17__FBSDID("$FreeBSD: head/lib/msun/src/s_expm1f.c 176082 2008-02-07 09:42:19Z bde $");
17__FBSDID("$FreeBSD: head/lib/msun/src/s_expm1f.c 176132 2008-02-09 12:53:15Z bde $");
18
19#include "math.h"
20#include "math_private.h"
21
22static const float
23one = 1.0,
24huge = 1.0e+30,
25tiny = 1.0e-30,
26o_threshold = 8.8721679688e+01,/* 0x42b17180 */
27ln2_hi = 6.9313812256e-01,/* 0x3f317180 */
28ln2_lo = 9.0580006145e-06,/* 0x3717f7d1 */
29invln2 = 1.4426950216e+00,/* 0x3fb8aa3b */
18
19#include "math.h"
20#include "math_private.h"
21
22static const float
23one = 1.0,
24huge = 1.0e+30,
25tiny = 1.0e-30,
26o_threshold = 8.8721679688e+01,/* 0x42b17180 */
27ln2_hi = 6.9313812256e-01,/* 0x3f317180 */
28ln2_lo = 9.0580006145e-06,/* 0x3717f7d1 */
29invln2 = 1.4426950216e+00,/* 0x3fb8aa3b */
30 /* scaled coefficients related to expm1 */
31Q1 = -3.3333335072e-02, /* 0xbd088889 */
32Q2 = 1.5873016091e-03, /* 0x3ad00d01 */
33Q3 = -7.9365076090e-05, /* 0xb8a670cd */
34Q4 = 4.0082177293e-06, /* 0x36867e54 */
35Q5 = -2.0109921195e-07; /* 0xb457edbb */
30/*
31 * Domain [-0.34568, 0.34568], range ~[-6.694e-10, 6.696e-10]:
32 * |6 / x * (1 + 2 * (1 / (exp(x) - 1) - 1 / x)) - q(x)| < 2**-30.04
33 * Scaled coefficients: Qn_here = 2**n * Qn_for_q (see s_expm1.c):
34 */
35Q1 = -3.3333212137e-2, /* -0x888868.0p-28 */
36Q2 = 1.5807170421e-3; /* 0xcf3010.0p-33 */
36
37float
38expm1f(float x)
39{
40 float y,hi,lo,c,t,e,hxs,hfx,r1,twopk;
41 int32_t k,xsb;
42 u_int32_t hx;
43

--- 37 unchanged lines hidden (view full) ---

81 t = huge+x; /* return x with inexact flags when x!=0 */
82 return x - (t-(huge+x));
83 }
84 else k = 0;
85
86 /* x is now in primary range */
87 hfx = (float)0.5*x;
88 hxs = x*hfx;
37
38float
39expm1f(float x)
40{
41 float y,hi,lo,c,t,e,hxs,hfx,r1,twopk;
42 int32_t k,xsb;
43 u_int32_t hx;
44

--- 37 unchanged lines hidden (view full) ---

82 t = huge+x; /* return x with inexact flags when x!=0 */
83 return x - (t-(huge+x));
84 }
85 else k = 0;
86
87 /* x is now in primary range */
88 hfx = (float)0.5*x;
89 hxs = x*hfx;
89 r1 = one+hxs*(Q1+hxs*(Q2+hxs*(Q3+hxs*(Q4+hxs*Q5))));
90 r1 = one+hxs*(Q1+hxs*Q2);
90 t = (float)3.0-r1*hfx;
91 e = hxs*((r1-t)/((float)6.0 - x*t));
92 if(k==0) return x - (x*e-hxs); /* c is 0 */
93 else {
94 SET_FLOAT_WORD(twopk,0x3f800000+(k<<23)); /* 2^k */
95 e = (x*(e-c)-c);
96 e -= hxs;
97 if(k== -1) return (float)0.5*(x-e)-(float)0.5;

--- 23 unchanged lines hidden --- 		91 t = (float)3.0-r1*hfx;
92 e = hxs*((r1-t)/((float)6.0 - x*t));
93 if(k==0) return x - (x*e-hxs); /* c is 0 */
94 else {
95 SET_FLOAT_WORD(twopk,0x3f800000+(k<<23)); /* 2^k */
96 e = (x*(e-c)-c);
97 e -= hxs;
98 if(k== -1) return (float)0.5*(x-e)-(float)0.5;

--- 23 unchanged lines hidden ---