source: trunk/minix/lib/ack/fphook/fif8.fc@ 10

/*
  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
  See the copyright notice in the ACK home directory, in the file "Copyright".
*/

/* $Header: /cvsup/minix/src/lib/ack/fphook/fif8.fc,v 1.1 2005/10/10 15:27:44 beng Exp $ */

/*
        MULTIPLY AND DISMEMBER PARTS (FIF 8)
*/

#include "FP_types.h"
#include "FP_shift.h"

void
fif8(p,x,y)
DOUBLE  x,y;
struct fif8_returns *p;
{

        EXTEND  e1,e2;

        extend(&y.d[0],&e1,sizeof(DOUBLE));
        extend(&x.d[0],&e2,sizeof(DOUBLE));
                /* do a multiply */
        mul_ext(&e1,&e2);
        e2 = e1;
        compact(&e2, &y.d[0], sizeof(DOUBLE));
        if (e1.exp < 0) {
                p->ipart.d[0] = 0;
                p->ipart.d[1] = 0;
                p->fpart = y;
                return;
        }
        if (e1.exp > 62 - DBL_M1LEFT) {
                p->ipart = y;
                p->fpart.d[0] = 0;
                p->fpart.d[1] = 0;
                return;
        }
        b64_sft(&e1.mantissa, 63 - e1.exp);
        b64_sft(&e1.mantissa, e1.exp - 63);     /* "loose" low order bits */
        compact(&e1, &(p->ipart.d[0]), sizeof(DOUBLE));
        extend(&(p->ipart.d[0]), &e2, sizeof(DOUBLE));
        extend(&y.d[0], &e1, sizeof(DOUBLE));
        sub_ext(&e1, &e2);
        compact(&e1, &(p->fpart.d[0]), sizeof(DOUBLE));
}