source: trunk/minix/lib/ack/float/cif4.fc@ 20

/*
  (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/float/cif4.fc,v 1.1 2005/10/10 15:27:42 beng Exp $ */

/*
        CONVERT INTEGER TO SINGLE (CIF n 4)

        THIS ROUTINE WORKS BY FILLING AN EXTENDED
        WITH THE INTEGER VALUE IN EXTENDED FORMAT
        AND USES COMPACT() TO PUT IT INTO THE PROPER
        FLOATING POINT PRECISION.
*/

#include "FP_types.h"

void
cif4(ss,src)
int     ss;     /* source size */
long    src;    /* largest possible integer to convert */
{
        EXTEND  buf;
        short   *ipt;
        long    i_src;
        SINGLE  *result;

        zrf_ext(&buf);
        if (ss == sizeof(long)) {
                buf.exp = 31;
                i_src = src;
                result = (SINGLE *) &src;
        }
        else    {
                ipt = (short *) &src;
                i_src = (long) *ipt;
                buf.exp = 15;
                result = (SINGLE *) &ss;
        }
        if (i_src == 0) {
                *result = (SINGLE) 0L;
                return;
        }
                        /* ESTABLISHED THAT src != 0    */
                        /* adjust exponent field        */
        buf.sign = (i_src < 0) ? 0x8000 : 0;
                        /* clear sign bit of integer    */
                        /* move to mantissa field       */
        buf.m1 = (i_src < 0) ? -i_src : i_src;
                        /* adjust mantissa field        */
        if (ss != sizeof(long))
                buf.m1 <<= 16;
        nrm_ext(&buf);          /* adjust mantissa field        */
        compact(&buf, result,sizeof(SINGLE));   /* put on stack */
}