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Annotation of 43BSDTahoe/usr.lib/libF77/z_div.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:  *     @(#)z_div.c     5.2     11/3/86
                      7:  */
                      8: 
                      9: #include "complex"
                     10: #include <stdio.h>
                     11: #include <errno.h>
                     12: #ifdef tahoe
                     13: #include <tahoemath/FP.h>
                     14: #endif tahoe
                     15: 
                     16: z_div(c, a, b)
                     17: dcomplex *a, *b, *c;
                     18: {
                     19: double ratio, den;
                     20: double abr, abi;
                     21: 
                     22: #ifndef tahoe
                     23: if( (abr = b->dreal) < 0.)
                     24:        abr = - abr;
                     25: if( (abi = b->dimag) < 0.)
                     26:        abi = - abi;
                     27: #else tahoe
                     28: if( (abr = b->dreal) < 0.)
                     29:        *((long int *)&abr) ^= SIGN_BIT;
                     30: if( (abi = b->dimag) < 0.)
                     31:        *((long int *)&abi) ^= SIGN_BIT;
                     32: #endif tahoe
                     33: if( abr <= abi )
                     34:        {
                     35:        if(abi == 0) {
                     36:                fprintf( stderr, "Double complex division by zero\n" );
                     37:                f77_abort(EDOM);
                     38:        }
                     39:        ratio = b->dreal / b->dimag ;
                     40:        den = b->dimag * (1 + ratio*ratio);
                     41:        c->dreal = (a->dreal*ratio + a->dimag) / den;
                     42:        c->dimag = (a->dimag*ratio - a->dreal) / den;
                     43:        }
                     44: 
                     45: else
                     46:        {
                     47:        ratio = b->dimag / b->dreal ;
                     48:        den = b->dreal * (1 + ratio*ratio);
                     49:        c->dreal = (a->dreal + a->dimag*ratio) / den;
                     50:        c->dimag = (a->dimag - a->dreal*ratio) / den;
                     51:        }
                     52: 
                     53: }

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