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Annotation of 43BSDTahoe/usr.lib/libF77/c_sqrt.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  * Copyright (c) 1980 Regents of the University of California.
                      3:  * All rights reserved.  The Berkeley software License Agreement
                      4:  * specifies the terms and conditions for redistribution.
                      5:  *
                      6:  *     @(#)c_sqrt.c    5.2     11/3/86
                      7:  */
                      8: 
                      9: #include "complex"
                     10: #ifdef tahoe
                     11: #include <tahoemath/FP.h>
                     12: #endif tahoe
                     13: 
                     14: c_sqrt(r, z)
                     15: complex *r, *z;
                     16: {
                     17: double mag, sqrt(), cabs();
                     18: 
                     19: if( (mag = cabs(z->real, z->imag)) == 0.)
                     20:        r->real = r->imag = 0.;
                     21: else if(z->real > 0)
                     22:        {
                     23:        r->real = sqrt(0.5 * (mag + z->real) );
                     24:        r->imag = z->imag / r->real / 2;
                     25:        }
                     26: else
                     27:        {
                     28:        r->imag = sqrt(0.5 * (mag - z->real) );
                     29:        if(z->imag < 0)
                     30: #ifndef tahoe
                     31:                r->imag = - r->imag;
                     32: #else tahoe
                     33:                *(unsigned long*)&(r->imag) ^= SIGN_BIT;
                     34: #endif tahoe
                     35:        r->real = z->imag / r->imag /2;
                     36:        }
                     37: }

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