Return to sincos.c CVS log

Up to [CSRG BSD Unix] / 43BSDTahoe / usr.lib / libm / common

Annotation of 43BSDTahoe/usr.lib/libm/common/sincos.c, 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 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.
                     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:  */
                     22: 
                     23: #ifndef lint
                     24: static char sccsid[] = "@(#)sincos.c   5.3 (Berkeley) 6/30/88";
                     25: #endif /* not lint */
                     26: 
                     27: #include "trig.h"
                     28: double
                     29: sin(x)
                     30: double x;
                     31: {
                     32:        double a,c,z;
                     33: 
                     34:         if(!finite(x))         /* sin(NaN) and sin(INF) must be NaN */
                     35:                return x-x;
                     36:        x=drem(x,PI2);          /* reduce x into [-PI,PI] */
                     37:        a=copysign(x,one);
                     38:        if (a >= PIo4) {
                     39:                if(a >= PI3o4)          /* ... in [3PI/4,PI] */
                     40:                        x = copysign((a = PI-a),x);
                     41:                else {                  /* ... in [PI/4,3PI/4]  */
                     42:                        a = PIo2-a;             /* rtn. sign(x)*C(PI/2-|x|) */
                     43:                        z = a*a;
                     44:                        c = cos__C(z);
                     45:                        z *= half;
                     46:                        a = (z >= thresh ? half-((z-half)-c) : one-(z-c));
                     47:                        return copysign(a,x);
                     48:                }
                     49:        }
                     50: 
                     51:        if (a < small) {                /* rtn. S(x) */
                     52:                big+a;
                     53:                return x;
                     54:        }
                     55:        return x+x*sin__S(x*x);
                     56: }
                     57: 
                     58: double
                     59: cos(x) 
                     60: double x;
                     61: {
                     62:        double a,c,z,s = 1.0;
                     63: 
                     64:        if(!finite(x))          /* cos(NaN) and cos(INF) must be NaN */
                     65:                return x-x;
                     66:        x=drem(x,PI2);          /* reduce x into [-PI,PI] */
                     67:        a=copysign(x,one);
                     68:        if (a >= PIo4) {
                     69:                if (a >= PI3o4) {       /* ... in [3PI/4,PI] */
                     70:                        a = PI-a;
                     71:                        s = negone;
                     72:                }
                     73:                else {                  /* ... in [PI/4,3PI/4] */
                     74:                        a = PIo2-a;
                     75:                        return a+a*sin__S(a*a); /* rtn. S(PI/2-|x|) */ 
                     76:                }
                     77:        }
                     78:        if (a < small) {
                     79:                big+a;
                     80:                return s;               /* rtn. s*C(a) */
                     81:        }
                     82:        z = a*a;
                     83:        c = cos__C(z);
                     84:        z *= half;
                     85:        a = (z >= thresh ? half-((z-half)-c) : one-(z-c));
                     86:        return copysign(a,s);
                     87: }

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.