Annotation of 43BSDReno/lib/libm/common/trig.h, revision 1.1.1.1

1.1       root        1: /*
                      2:  * Copyright (c) 1987 Regents of the University of California.
                      3:  * All rights reserved.
                      4:  *
                      5:  * Redistribution and use in source and binary forms are permitted
                      6:  * provided that: (1) source distributions retain this entire copyright
                      7:  * notice and comment, and (2) distributions including binaries display
                      8:  * the following acknowledgement:  ``This product includes software
                      9:  * developed by the University of California, Berkeley and its contributors''
                     10:  * in the documentation or other materials provided with the distribution
                     11:  * and in all advertising materials mentioning features or use of this
                     12:  * software. Neither the name of the University nor the names of its
                     13:  * contributors may be used to endorse or promote products derived
                     14:  * from this software without specific prior written permission.
                     15:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
                     16:  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
                     17:  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
                     18:  *
                     19:  * All recipients should regard themselves as participants in an ongoing
                     20:  * research project and hence should feel obligated to report their
                     21:  * experiences (good or bad) with these elementary function codes, using
                     22:  * the sendbug(8) program, to the authors.
                     23:  *
                     24:  *     @(#)trig.h      5.5 (Berkeley) 6/1/90
                     25:  */
                     26: 
                     27: #include "mathimpl.h"
                     28: 
                     29: vc(thresh, 2.6117239648121182150E-1 ,b863,3f85,6ea0,6b02, -1, .85B8636B026EA0)
                     30: vc(PIo4,   7.8539816339744830676E-1 ,0fda,4049,68c2,a221,  0, .C90FDAA22168C2)
                     31: vc(PIo2,   1.5707963267948966135E0  ,0fda,40c9,68c2,a221,  1, .C90FDAA22168C2)
                     32: vc(PI3o4,  2.3561944901923449203E0  ,cbe3,4116,0e92,f999,  2, .96CBE3F9990E92)
                     33: vc(PI,     3.1415926535897932270E0  ,0fda,4149,68c2,a221,  2, .C90FDAA22168C2)
                     34: vc(PI2,    6.2831853071795864540E0  ,0fda,41c9,68c2,a221,  3, .C90FDAA22168C2)
                     35: 
                     36: ic(thresh, 2.6117239648121182150E-1 , -2, 1.0B70C6D604DD4)
                     37: ic(PIo4,   7.8539816339744827900E-1 , -1, 1.921FB54442D18)
                     38: ic(PIo2,   1.5707963267948965580E0  ,  0, 1.921FB54442D18)
                     39: ic(PI3o4,  2.3561944901923448370E0  ,  1, 1.2D97C7F3321D2)
                     40: ic(PI,     3.1415926535897931160E0  ,  1, 1.921FB54442D18)
                     41: ic(PI2,    6.2831853071795862320E0  ,  2, 1.921FB54442D18)
                     42: 
                     43: #ifdef vccast
                     44: #define        thresh  vccast(thresh)
                     45: #define        PIo4    vccast(PIo4)
                     46: #define        PIo2    vccast(PIo2)
                     47: #define        PI3o4   vccast(PI3o4)
                     48: #define        PI      vccast(PI)
                     49: #define        PI2     vccast(PI2)
                     50: #endif
                     51: 
                     52: #ifdef national
                     53: static long fmaxx[]    = { 0xffffffff, 0x7fefffff};
                     54: #define   fmax    (*(double*)fmaxx)
                     55: #endif /* national */
                     56: 
                     57: static const double
                     58:        zero = 0,
                     59:        one = 1,
                     60:        negone = -1,
                     61:        half = 1.0/2.0, 
                     62:        small = 1E-10,  /* 1+small**2 == 1; better values for small:
                     63:                         *              small   = 1.5E-9 for VAX D
                     64:                         *                      = 1.2E-8 for IEEE Double
                     65:                         *                      = 2.8E-10 for IEEE Extended
                     66:                         */
                     67:        big = 1E20;     /* big := 1/(small**2) */
                     68: 
                     69: /* sin__S(x*x) ... re-implemented as a macro
                     70:  * DOUBLE PRECISION (VAX D format 56 bits, IEEE DOUBLE 53 BITS)
                     71:  * STATIC KERNEL FUNCTION OF SIN(X), COS(X), AND TAN(X) 
                     72:  * CODED IN C BY K.C. NG, 1/21/85; 
                     73:  * REVISED BY K.C. NG on 8/13/85.
                     74:  *
                     75:  *         sin(x*k) - x
                     76:  * RETURN  --------------- on [-PI/4,PI/4] , where k=pi/PI, PI is the rounded
                     77:  *                 x   
                     78:  * value of pi in machine precision:
                     79:  *
                     80:  *     Decimal:
                     81:  *             pi = 3.141592653589793 23846264338327 ..... 
                     82:  *    53 bits   PI = 3.141592653589793 115997963 ..... ,
                     83:  *    56 bits   PI = 3.141592653589793 227020265 ..... ,  
                     84:  *
                     85:  *     Hexadecimal:
                     86:  *             pi = 3.243F6A8885A308D313198A2E....
                     87:  *    53 bits   PI = 3.243F6A8885A30  =  2 * 1.921FB54442D18
                     88:  *    56 bits   PI = 3.243F6A8885A308 =  4 * .C90FDAA22168C2    
                     89:  *
                     90:  * Method:
                     91:  *     1. Let z=x*x. Create a polynomial approximation to 
                     92:  *         (sin(k*x)-x)/x  =  z*(S0 + S1*z^1 + ... + S5*z^5).
                     93:  *     Then
                     94:  *      sin__S(x*x) = z*(S0 + S1*z^1 + ... + S5*z^5)
                     95:  *
                     96:  *     The coefficient S's are obtained by a special Remez algorithm.
                     97:  *
                     98:  * Accuracy:
                     99:  *     In the absence of rounding error, the approximation has absolute error 
                    100:  *     less than 2**(-61.11) for VAX D FORMAT, 2**(-57.45) for IEEE DOUBLE. 
                    101:  *
                    102:  * Constants:
                    103:  * The hexadecimal values are the intended ones for the following constants.
                    104:  * The decimal values may be used, provided that the compiler will convert
                    105:  * from decimal to binary accurately enough to produce the hexadecimal values
                    106:  * shown.
                    107:  *
                    108:  */
                    109: 
                    110: vc(S0, -1.6666666666666646660E-1  ,aaaa,bf2a,aa71,aaaa,  -2, -.AAAAAAAAAAAA71)
                    111: vc(S1,  8.3333333333297230413E-3  ,8888,3d08,477f,8888,  -6,  .8888888888477F)
                    112: vc(S2, -1.9841269838362403710E-4  ,0d00,ba50,1057,cf8a, -12, -.D00D00CF8A1057)
                    113: vc(S3,  2.7557318019967078930E-6  ,ef1c,3738,bedc,a326, -18,  .B8EF1CA326BEDC)
                    114: vc(S4, -2.5051841873876551398E-8  ,3195,b3d7,e1d3,374c, -25, -.D73195374CE1D3)
                    115: vc(S5,  1.6028995389845827653E-10 ,3d9c,3030,cccc,6d26, -32,  .B03D9C6D26CCCC)
                    116: vc(S6, -6.2723499671769283121E-13 ,8d0b,ac30,ea82,7561, -40, -.B08D0B7561EA82)
                    117: 
                    118: ic(S0, -1.6666666666666463126E-1  ,  -3, -1.555555555550C)
                    119: ic(S1,  8.3333333332992771264E-3  ,  -7,  1.111111110C461)
                    120: ic(S2, -1.9841269816180999116E-4  , -13, -1.A01A019746345)
                    121: ic(S3,  2.7557309793219876880E-6  , -19,  1.71DE3209CDCD9)
                    122: ic(S4, -2.5050225177523807003E-8  , -26, -1.AE5C0E319A4EF)
                    123: ic(S5,  1.5868926979889205164E-10 , -33,  1.5CF61DF672B13)
                    124: 
                    125: #ifdef vccast
                    126: #define        S0      vccast(S0)
                    127: #define        S1      vccast(S1)
                    128: #define        S2      vccast(S2)
                    129: #define        S3      vccast(S3)
                    130: #define        S4      vccast(S4)
                    131: #define        S5      vccast(S5)
                    132: #define        S6      vccast(S6)
                    133: #endif
                    134: 
                    135: #if defined(vax)||defined(tahoe)
                    136: #  define      sin__S(z)       (z*(S0+z*(S1+z*(S2+z*(S3+z*(S4+z*(S5+z*S6)))))))
                    137: #else  /* defined(vax)||defined(tahoe) */
                    138: #  define      sin__S(z)       (z*(S0+z*(S1+z*(S2+z*(S3+z*(S4+z*S5))))))
                    139: #endif         /* defined(vax)||defined(tahoe) */
                    140: 
                    141: /* cos__C(x*x) ... re-implemented as a macro
                    142:  * DOUBLE PRECISION (VAX D FORMAT 56 BITS, IEEE DOUBLE 53 BITS)
                    143:  * STATIC KERNEL FUNCTION OF SIN(X), COS(X), AND TAN(X) 
                    144:  * CODED IN C BY K.C. NG, 1/21/85; 
                    145:  * REVISED BY K.C. NG on 8/13/85.
                    146:  *
                    147:  *                         x*x 
                    148:  * RETURN   cos(k*x) - 1 + ----- on [-PI/4,PI/4],  where k = pi/PI,
                    149:  *                          2  
                    150:  * PI is the rounded value of pi in machine precision :
                    151:  *
                    152:  *     Decimal:
                    153:  *             pi = 3.141592653589793 23846264338327 ..... 
                    154:  *    53 bits   PI = 3.141592653589793 115997963 ..... ,
                    155:  *    56 bits   PI = 3.141592653589793 227020265 ..... ,  
                    156:  *
                    157:  *     Hexadecimal:
                    158:  *             pi = 3.243F6A8885A308D313198A2E....
                    159:  *    53 bits   PI = 3.243F6A8885A30  =  2 * 1.921FB54442D18
                    160:  *    56 bits   PI = 3.243F6A8885A308 =  4 * .C90FDAA22168C2    
                    161:  *
                    162:  *
                    163:  * Method:
                    164:  *     1. Let z=x*x. Create a polynomial approximation to 
                    165:  *         cos(k*x)-1+z/2  =  z*z*(C0 + C1*z^1 + ... + C5*z^5)
                    166:  *     then
                    167:  *      cos__C(z) =  z*z*(C0 + C1*z^1 + ... + C5*z^5)
                    168:  *
                    169:  *     The coefficient C's are obtained by a special Remez algorithm.
                    170:  *
                    171:  * Accuracy:
                    172:  *     In the absence of rounding error, the approximation has absolute error 
                    173:  *     less than 2**(-64) for VAX D FORMAT, 2**(-58.3) for IEEE DOUBLE. 
                    174:  *     
                    175:  *
                    176:  * Constants:
                    177:  * The hexadecimal values are the intended ones for the following constants.
                    178:  * The decimal values may be used, provided that the compiler will convert
                    179:  * from decimal to binary accurately enough to produce the hexadecimal values
                    180:  * shown.
                    181:  */
                    182: 
                    183: vc(C0,  4.1666666666666504759E-2  ,aaaa,3e2a,a9f0,aaaa,  -4,  .AAAAAAAAAAA9F0)
                    184: vc(C1, -1.3888888888865302059E-3  ,0b60,bbb6,0cca,b60a,  -9, -.B60B60B60A0CCA)
                    185: vc(C2,  2.4801587285601038265E-5  ,0d00,38d0,098f,cdcd, -15,  .D00D00CDCD098F)
                    186: vc(C3, -2.7557313470902390219E-7  ,f27b,b593,e805,b593, -21, -.93F27BB593E805)
                    187: vc(C4,  2.0875623401082232009E-9  ,74c8,320f,3ff0,fa1e, -28,  .8F74C8FA1E3FF0)
                    188: vc(C5, -1.1355178117642986178E-11 ,c32d,ae47,5a63,0a5c, -36, -.C7C32D0A5C5A63)
                    189: 
                    190: ic(C0,  4.1666666666666504759E-2  ,  -5,  1.555555555553E)
                    191: ic(C1, -1.3888888888865301516E-3  , -10, -1.6C16C16C14199)
                    192: ic(C2,  2.4801587269650015769E-5  , -16,  1.A01A01971CAEB)
                    193: ic(C3, -2.7557304623183959811E-7  , -22, -1.27E4F1314AD1A)
                    194: ic(C4,  2.0873958177697780076E-9  , -29,  1.1EE3B60DDDC8C)
                    195: ic(C5, -1.1250289076471311557E-11 , -37, -1.8BD5986B2A52E)
                    196: 
                    197: #ifdef vccast
                    198: #define        C0      vccast(C0)
                    199: #define        C1      vccast(C1)
                    200: #define        C2      vccast(C2)
                    201: #define        C3      vccast(C3)
                    202: #define        C4      vccast(C4)
                    203: #define        C5      vccast(C5)
                    204: #endif
                    205: 
                    206: #define cos__C(z)      (z*z*(C0+z*(C1+z*(C2+z*(C3+z*(C4+z*C5))))))

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