Return to pow_zi.c CVS log

Up to [CSRG BSD Unix] / 42BSD / usr.lib / libF77

Annotation of 42BSD/usr.lib/libF77/pow_zi.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  *     "@(#)pow_zi.c   1.1"
                      3:  */
                      4: 
                      5: #include "complex"
                      6: 
                      7: pow_zi(p, a, b)        /* p = a**b  */
                      8: dcomplex *p, *a;
                      9: long int *b;
                     10: {
                     11: long int n;
                     12: double t;
                     13: dcomplex x;
                     14: 
                     15: n = *b;
                     16: p->dreal = 1;
                     17: p->dimag = 0;
                     18: 
                     19: if(n == 0)
                     20:        return;
                     21: if(n < 0)
                     22:        {
                     23:        n = -n;
                     24:        z_div(&x, p, a);
                     25:        }
                     26: else
                     27:        {
                     28:        x.dreal = a->dreal;
                     29:        x.dimag = a->dimag;
                     30:        }
                     31: 
                     32: for( ; ; )
                     33:        {
                     34:        if(n & 01)
                     35:                {
                     36:                t = p->dreal * x.dreal - p->dimag * x.dimag;
                     37:                p->dimag = p->dreal * x.dimag + p->dimag * x.dreal;
                     38:                p->dreal = t;
                     39:                }
                     40:        if(n >>= 1)
                     41:                {
                     42:                t = x.dreal * x.dreal - x.dimag * x.dimag;
                     43:                x.dimag = 2 * x.dreal * x.dimag;
                     44:                x.dreal = t;
                     45:                }
                     46:        else
                     47:                break;
                     48:        }
                     49: }

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