Return to asin.c CVS log

Up to [Research Unix] / researchv9 / libc / math

Annotation of researchv9/libc/math/asin.c, revision 1.1.1.1

1.1       root        1: /*
                      2:        asin(arg) and acos(arg) return the arcsin, arccos,
                      3:        respectively of their arguments.
                      4: 
                      5:        Arctan is called after appropriate range reduction.
                      6: */
                      7: 
                      8: #include       <errno.h>
                      9: int errno;
                     10: double atan();
                     11: double sqrt();
                     12: static double pio2     = 1.570796326794896619;
                     13: 
                     14: double
                     15: asin(arg) double arg; {
                     16: 
                     17:        double sign, temp;
                     18: 
                     19:        sign = 1.;
                     20:        if(arg <0){
                     21:                arg = -arg;
                     22:                sign = -1.;
                     23:        }
                     24: 
                     25:        if(arg > 1.){
                     26:                errno = EDOM;
                     27:                return(0.);
                     28:        }
                     29: 
                     30:        temp = sqrt(1. - arg*arg);
                     31:        if(arg > 0.7)
                     32:                temp = pio2 - atan(temp/arg);
                     33:        else
                     34:                temp = atan(arg/temp);
                     35: 
                     36:        return(sign*temp);
                     37: }
                     38: 
                     39: double
                     40: acos(arg) double arg; {
                     41: 
                     42:        if((arg > 1.) || (arg < -1.)){
                     43:                errno = EDOM;
                     44:                return(0.);
                     45:        }
                     46: 
                     47:        return(pio2 - asin(arg));
                     48: }

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