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Annotation of cci/usr/src/usr.lib/libF77/z_sqrt.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  *     "@(#)z_sqrt.c   1.1"
                      3:  */
                      4: 
                      5: #include "complex"
                      6: 
                      7: /* THIS IS BASED ON THE TAHOE FP REPRESENTATION */
                      8: #include <FP.h>
                      9: 
                     10: z_sqrt(r, z)
                     11: dcomplex *r, *z;
                     12: {
                     13: double mag, sqrt(), zabs();
                     14: 
                     15: if( (mag = zabs(z->dreal, z->dimag)) == 0.)
                     16:        r->dreal = r->dimag = 0.;
                     17: else if(z->dreal > 0)
                     18:        {
                     19:        r->dreal = sqrt(0.5 * (mag + z->dreal) );
                     20:        r->dimag = z->dimag / r->dreal / 2;
                     21:        }
                     22: else
                     23:        {
                     24:        r->dimag = sqrt(0.5 * (mag - z->dreal) );
                     25:        if(z->dimag < 0)
                     26:                *((long int *)&r->dimag) ^= SIGN_BIT;
                     27:        r->dreal = z->dimag / r->dimag / 2;
                     28:        }
                     29: }

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