date and time created 88/08/31 23:01:12 by bostic
[unix-history] / usr / src / lib / libm / common / trig.h
CommitLineData
9b525f39 1/*
38cc45a4 2 * Copyright (c) 1987 Regents of the University of California.
9b525f39
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3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms are permitted
a399f6c8
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6 * provided that the above copyright notice and this paragraph are
7 * duplicated in all such forms and that any documentation,
8 * advertising materials, and other materials related to such
9 * distribution and use acknowledge that the software was developed
10 * by the University of California, Berkeley. The name of the
11 * University may not be used to endorse or promote products derived
12 * from this software without specific prior written permission.
13 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
15 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
9b525f39
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16 *
17 * All recipients should regard themselves as participants in an ongoing
18 * research project and hence should feel obligated to report their
19 * experiences (good or bad) with these elementary function codes, using
20 * the sendbug(8) program, to the authors.
21 *
a399f6c8 22 * @(#)trig.h 5.3 (Berkeley) %G%
38cc45a4 23 */
9b525f39 24
38cc45a4
ZAL
25#if defined(vax)||defined(tahoe)
26#ifdef vax
27#define _0x(A,B) 0x/**/A/**/B
28#else /* vax */
29#define _0x(A,B) 0x/**/B/**/A
30#endif /* vax */
31/*thresh = 2.6117239648121182150E-1 , Hex 2^ -1 * .85B8636B026EA0 */
32/*PIo4 = 7.8539816339744830676E-1 , Hex 2^ 0 * .C90FDAA22168C2 */
33/*PIo2 = 1.5707963267948966135E0 , Hex 2^ 1 * .C90FDAA22168C2 */
34/*PI3o4 = 2.3561944901923449203E0 , Hex 2^ 2 * .96CBE3F9990E92 */
35/*PI = 3.1415926535897932270E0 , Hex 2^ 2 * .C90FDAA22168C2 */
36/*PI2 = 6.2831853071795864540E0 ; Hex 2^ 3 * .C90FDAA22168C2 */
37static long threshx[] = { _0x(b863,3f85), _0x(6ea0,6b02)};
38static long PIo4x[] = { _0x(0fda,4049), _0x(68c2,a221)};
39static long PIo2x[] = { _0x(0fda,40c9), _0x(68c2,a221)};
40static long PI3o4x[] = { _0x(cbe3,4116), _0x(0e92,f999)};
41static long PIx[] = { _0x(0fda,4149), _0x(68c2,a221)};
42static long PI2x[] = { _0x(0fda,41c9), _0x(68c2,a221)};
43#define thresh (*(double*)threshx)
44#define PIo4 (*(double*)PIo4x)
45#define PIo2 (*(double*)PIo2x)
46#define PI3o4 (*(double*)PI3o4x)
47#define PI (*(double*)PIx)
48#define PI2 (*(double*)PI2x)
49#else /* defined(vax)||defined(tahoe) */
50static double
51thresh = 2.6117239648121182150E-1 , /*Hex 2^ -2 * 1.0B70C6D604DD4 */
52PIo4 = 7.8539816339744827900E-1 , /*Hex 2^ -1 * 1.921FB54442D18 */
53PIo2 = 1.5707963267948965580E0 , /*Hex 2^ 0 * 1.921FB54442D18 */
54PI3o4 = 2.3561944901923448370E0 , /*Hex 2^ 1 * 1.2D97C7F3321D2 */
55PI = 3.1415926535897931160E0 , /*Hex 2^ 1 * 1.921FB54442D18 */
56PI2 = 6.2831853071795862320E0 ; /*Hex 2^ 2 * 1.921FB54442D18 */
57#ifdef national
58static long fmaxx[] = { 0xffffffff, 0x7fefffff};
59#define fmax (*(double*)fmaxx)
60#endif /* national */
61#endif /* defined(vax)||defined(tahoe) */
62static double
63 zero = 0,
64 one = 1,
65 negone = -1,
66 half = 1.0/2.0,
67 small = 1E-10, /* 1+small**2 == 1; better values for small:
68 * small = 1.5E-9 for VAX D
69 * = 1.2E-8 for IEEE Double
70 * = 2.8E-10 for IEEE Extended
71 */
72 big = 1E20; /* big := 1/(small**2) */
73
74/* sin__S(x*x) ... re-implemented as a macro
75 * DOUBLE PRECISION (VAX D format 56 bits, IEEE DOUBLE 53 BITS)
76 * STATIC KERNEL FUNCTION OF SIN(X), COS(X), AND TAN(X)
77 * CODED IN C BY K.C. NG, 1/21/85;
78 * REVISED BY K.C. NG on 8/13/85.
79 *
80 * sin(x*k) - x
81 * RETURN --------------- on [-PI/4,PI/4] , where k=pi/PI, PI is the rounded
82 * x
83 * value of pi in machine precision:
84 *
85 * Decimal:
86 * pi = 3.141592653589793 23846264338327 .....
87 * 53 bits PI = 3.141592653589793 115997963 ..... ,
88 * 56 bits PI = 3.141592653589793 227020265 ..... ,
89 *
90 * Hexadecimal:
91 * pi = 3.243F6A8885A308D313198A2E....
92 * 53 bits PI = 3.243F6A8885A30 = 2 * 1.921FB54442D18
93 * 56 bits PI = 3.243F6A8885A308 = 4 * .C90FDAA22168C2
94 *
95 * Method:
96 * 1. Let z=x*x. Create a polynomial approximation to
97 * (sin(k*x)-x)/x = z*(S0 + S1*z^1 + ... + S5*z^5).
98 * Then
99 * sin__S(x*x) = z*(S0 + S1*z^1 + ... + S5*z^5)
100 *
101 * The coefficient S's are obtained by a special Remez algorithm.
102 *
103 * Accuracy:
104 * In the absence of rounding error, the approximation has absolute error
105 * less than 2**(-61.11) for VAX D FORMAT, 2**(-57.45) for IEEE DOUBLE.
106 *
107 * Constants:
108 * The hexadecimal values are the intended ones for the following constants.
109 * The decimal values may be used, provided that the compiler will convert
110 * from decimal to binary accurately enough to produce the hexadecimal values
111 * shown.
112 *
113 */
114
115#if defined(vax)||defined(tahoe)
116/*S0 = -1.6666666666666646660E-1 , Hex 2^ -2 * -.AAAAAAAAAAAA71 */
117/*S1 = 8.3333333333297230413E-3 , Hex 2^ -6 * .8888888888477F */
118/*S2 = -1.9841269838362403710E-4 , Hex 2^-12 * -.D00D00CF8A1057 */
119/*S3 = 2.7557318019967078930E-6 , Hex 2^-18 * .B8EF1CA326BEDC */
120/*S4 = -2.5051841873876551398E-8 , Hex 2^-25 * -.D73195374CE1D3 */
121/*S5 = 1.6028995389845827653E-10 , Hex 2^-32 * .B03D9C6D26CCCC */
122/*S6 = -6.2723499671769283121E-13 ; Hex 2^-40 * -.B08D0B7561EA82 */
123static long S0x[] = { _0x(aaaa,bf2a), _0x(aa71,aaaa)};
124static long S1x[] = { _0x(8888,3d08), _0x(477f,8888)};
125static long S2x[] = { _0x(0d00,ba50), _0x(1057,cf8a)};
126static long S3x[] = { _0x(ef1c,3738), _0x(bedc,a326)};
127static long S4x[] = { _0x(3195,b3d7), _0x(e1d3,374c)};
128static long S5x[] = { _0x(3d9c,3030), _0x(cccc,6d26)};
129static long S6x[] = { _0x(8d0b,ac30), _0x(ea82,7561)};
130#define S0 (*(double*)S0x)
131#define S1 (*(double*)S1x)
132#define S2 (*(double*)S2x)
133#define S3 (*(double*)S3x)
134#define S4 (*(double*)S4x)
135#define S5 (*(double*)S5x)
136#define S6 (*(double*)S6x)
137#else /* IEEE double */
138static double
139S0 = -1.6666666666666463126E-1 , /*Hex 2^ -3 * -1.555555555550C */
140S1 = 8.3333333332992771264E-3 , /*Hex 2^ -7 * 1.111111110C461 */
141S2 = -1.9841269816180999116E-4 , /*Hex 2^-13 * -1.A01A019746345 */
142S3 = 2.7557309793219876880E-6 , /*Hex 2^-19 * 1.71DE3209CDCD9 */
143S4 = -2.5050225177523807003E-8 , /*Hex 2^-26 * -1.AE5C0E319A4EF */
144S5 = 1.5868926979889205164E-10 ; /*Hex 2^-33 * 1.5CF61DF672B13 */
145#endif
146
147#if defined(vax)||defined(tahoe)
148#define sin__S(z) (z*(S0+z*(S1+z*(S2+z*(S3+z*(S4+z*(S5+z*S6)))))))
149#else /* defined(vax)||defined(tahoe) */
150#define sin__S(z) (z*(S0+z*(S1+z*(S2+z*(S3+z*(S4+z*S5))))))
151#endif /* defined(vax)||defined(tahoe) */
152
153/* cos__C(x*x) ... re-implemented as a macro
154 * DOUBLE PRECISION (VAX D FORMAT 56 BITS, IEEE DOUBLE 53 BITS)
155 * STATIC KERNEL FUNCTION OF SIN(X), COS(X), AND TAN(X)
156 * CODED IN C BY K.C. NG, 1/21/85;
157 * REVISED BY K.C. NG on 8/13/85.
158 *
159 * x*x
160 * RETURN cos(k*x) - 1 + ----- on [-PI/4,PI/4], where k = pi/PI,
161 * 2
162 * PI is the rounded value of pi in machine precision :
163 *
164 * Decimal:
165 * pi = 3.141592653589793 23846264338327 .....
166 * 53 bits PI = 3.141592653589793 115997963 ..... ,
167 * 56 bits PI = 3.141592653589793 227020265 ..... ,
168 *
169 * Hexadecimal:
170 * pi = 3.243F6A8885A308D313198A2E....
171 * 53 bits PI = 3.243F6A8885A30 = 2 * 1.921FB54442D18
172 * 56 bits PI = 3.243F6A8885A308 = 4 * .C90FDAA22168C2
173 *
174 *
175 * Method:
176 * 1. Let z=x*x. Create a polynomial approximation to
177 * cos(k*x)-1+z/2 = z*z*(C0 + C1*z^1 + ... + C5*z^5)
178 * then
179 * cos__C(z) = z*z*(C0 + C1*z^1 + ... + C5*z^5)
180 *
181 * The coefficient C's are obtained by a special Remez algorithm.
182 *
183 * Accuracy:
184 * In the absence of rounding error, the approximation has absolute error
185 * less than 2**(-64) for VAX D FORMAT, 2**(-58.3) for IEEE DOUBLE.
186 *
187 *
188 * Constants:
189 * The hexadecimal values are the intended ones for the following constants.
190 * The decimal values may be used, provided that the compiler will convert
191 * from decimal to binary accurately enough to produce the hexadecimal values
192 * shown.
193 *
194 */
195
196#if defined(vax)||defined(tahoe)
197/*C0 = 4.1666666666666504759E-2 , Hex 2^ -4 * .AAAAAAAAAAA9F0 */
198/*C1 = -1.3888888888865302059E-3 , Hex 2^ -9 * -.B60B60B60A0CCA */
199/*C2 = 2.4801587285601038265E-5 , Hex 2^-15 * .D00D00CDCD098F */
200/*C3 = -2.7557313470902390219E-7 , Hex 2^-21 * -.93F27BB593E805 */
201/*C4 = 2.0875623401082232009E-9 , Hex 2^-28 * .8F74C8FA1E3FF0 */
202/*C5 = -1.1355178117642986178E-11 ; Hex 2^-36 * -.C7C32D0A5C5A63 */
203static long C0x[] = { _0x(aaaa,3e2a), _0x(a9f0,aaaa)};
204static long C1x[] = { _0x(0b60,bbb6), _0x(0cca,b60a)};
205static long C2x[] = { _0x(0d00,38d0), _0x(098f,cdcd)};
206static long C3x[] = { _0x(f27b,b593), _0x(e805,b593)};
207static long C4x[] = { _0x(74c8,320f), _0x(3ff0,fa1e)};
208static long C5x[] = { _0x(c32d,ae47), _0x(5a63,0a5c)};
209#define C0 (*(double*)C0x)
210#define C1 (*(double*)C1x)
211#define C2 (*(double*)C2x)
212#define C3 (*(double*)C3x)
213#define C4 (*(double*)C4x)
214#define C5 (*(double*)C5x)
215#else /* defined(vax)||defined(tahoe) */
216static double
217C0 = 4.1666666666666504759E-2 , /*Hex 2^ -5 * 1.555555555553E */
218C1 = -1.3888888888865301516E-3 , /*Hex 2^-10 * -1.6C16C16C14199 */
219C2 = 2.4801587269650015769E-5 , /*Hex 2^-16 * 1.A01A01971CAEB */
220C3 = -2.7557304623183959811E-7 , /*Hex 2^-22 * -1.27E4F1314AD1A */
221C4 = 2.0873958177697780076E-9 , /*Hex 2^-29 * 1.1EE3B60DDDC8C */
222C5 = -1.1250289076471311557E-11 ; /*Hex 2^-37 * -1.8BD5986B2A52E */
223#endif /* defined(vax)||defined(tahoe) */
224
225#define cos__C(z) (z*z*(C0+z*(C1+z*(C2+z*(C3+z*(C4+z*C5))))))
226
227extern int finite();
228extern double copysign(),drem();