updated files; from Zhishun Alex Liu

[unix-history] / usr / src / usr.bin / f77 / libF77 / pow_ci.c

/*
* Copyright (c) 1980 Regents of the University of California.
* All rights reserved.  The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*
*      @(#)pow_ci.c    5.3     %G%
*/

#include "complex"

#ifdef tahoe

#define C_MULEQ(A,B)    \
       t = (A).real * (B).real - (A).imag * (B).imag,\
       (A).imag = (A).real * (B).imag + (A).imag * (B).real,\
       (A).real = t    /* A *= B */

void
pow_ci(p, a, b)         /* p = a**b  */
       complex *p, *a;
       long *b;
{
       register long n = *b;
       register float t;
       complex x;

       x = *a;
       p->real = (float)1, p->imag = (float)0;
       if (!n)
               return;
       if (n < 0) {
               c_div(&x, p, a);
               n = -n;
       }
       while (!(n&1)) {
               C_MULEQ(x, x);
               n >>= 1;
       }
       for (*p = x; --n > 0; C_MULEQ(*p, x))
               while (!(n&1)) {
                       C_MULEQ(x, x);
                       n >>= 1;
               }
}

#else /* !tahoe */

extern void pow_zi();

void
pow_ci(p, a, b)         /* p = a**b  */
       complex *p, *a;
       long *b;
{
       dcomplex p1, a1;

       a1.dreal = a->real;
       a1.dimag = a->imag;

       pow_zi(&p1, &a1, b);

       p->real = p1.dreal;
       p->imag = p1.dimag;
}

#endif /* tahoe */