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Annotation of cci/usr/src/usr.lib/libF77/z_div.c, revision 1.1

1.1     ! root        1: /*
        !             2:  *     @(#)z_div.c     2.1     6/7/85
        !             3:  */
        !             4: 
        !             5: #include "complex"
        !             6: #include <stdio.h>
        !             7: #include <errno.h>
        !             8: 
        !             9: /* THIS IS BASED ON TAHOE FP REPRESENTATION! */
        !            10: #include <FP.h>
        !            11: 
        !            12: z_div(c, a, b)
        !            13: dcomplex *a, *b, *c;
        !            14: {
        !            15: double ratio, den;
        !            16: double abr, abi;
        !            17: 
        !            18: if( (abr = b->dreal) < 0.)
        !            19:        *((long int *)&abr) ^= SIGN_BIT;
        !            20: if( (abi = b->dimag) < 0.)
        !            21:        *((long int *)&abi) ^= SIGN_BIT;
        !            22: if( abr <= abi )
        !            23:        {
        !            24:        if(abi == 0) {
        !            25:                fprintf( stderr, "Double complex division by zero\n" );
        !            26:                /* f77_abort(EDOM); */
        !            27:        }
        !            28:        ratio = b->dreal / b->dimag ;
        !            29:        den = b->dimag * (1 + ratio*ratio);
        !            30:        c->dreal = (a->dreal*ratio + a->dimag) / den;
        !            31:        c->dimag = (a->dimag*ratio - a->dreal) / den;
        !            32:        }
        !            33: 
        !            34: else
        !            35:        {
        !            36:        ratio = b->dimag / b->dreal ;
        !            37:        den = b->dreal * (1 + ratio*ratio);
        !            38:        c->dreal = (a->dreal + a->dimag*ratio) / den;
        !            39:        c->dimag = (a->dimag - a->dreal*ratio) / den;
        !            40:        }
        !            41: 
        !            42: }

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