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