source: trunk/minix/lib/ack/fphook/cfu.fc@ 12

/*
  (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/cfu.fc,v 1.1 2005/10/10 15:27:43 beng Exp $ */

/*
                CONVERT FLOAT TO UNSIGNED (CFU m n)

                N.B. The caller must know what it is getting.
                     A LONG is always returned. If it is an
                     integer the high byte is cleared first.
*/

#include "FP_trap.h"
#include "FP_types.h"

long
cfu(ds,ss,src)
int     ds;     /* destination size (2 or 4) */
int     ss;     /* source size      (4 or 8) */
DOUBLE  src;    /* assume worst case */
{
        EXTEND  buf;
        long    new;
        short   newint, max_exp;

        extend(&src.d[0],&buf,ss);      /* get extended format  */
        if (buf.exp < 0) {      /* no conversion needed */
                src.d[ss == 8] = 0L;
                return(0L);
        }
        max_exp = (ds << 3) - 1;
        if (buf.exp > max_exp) {
                trap(EIOVFL);   /* integer overflow     */
                buf.exp %= max_exp;
        }
        new = buf.m1 >> (31-buf.exp);
done:
        src.d[ss == 8] = new;
        return(new);
}