/* DEC	*MultiplyDecimalAndTruncate(pDst,pSrc1,pSrc2,nid);
 *
 * ARGUMENT
 *	DEC	*pDst;
 *	DEC	*pSrc1,pSrc2;
 *	int	nid;
 *
 * DESCRIPTION
 *	Multiplies pSrc1 by pSrc2, storing the result in pDst.	The product is
 *  calculated to nid decimal places.
 *
 * SIDE	EFFECTS
 *	*pDst is indeterminate on overflow, underflow.
 *
 * RETURNS
 *	Returns	pointer	to pDst	if successful, otherwise a GM_NULL. The
 *   type error	(GM_OVERFLOW, GM_UNDERFLOW, GM_NOMEMORY) is in wGMError
 *   if	wGMError doesn't contain a previous error.
 *
 * POSSIBLE ERROR CODES
 *
 *	GM_NULLPOINTER
 *	GM_NOMEMORY
 *	GM_INVALIDID
 *	GM_OVERFLOW
 *	GM_UNDERFLOW
 *
 * AUTHOR
 *  Jared Levy	 05-JAN-1987  17:30
 *   Copyright (C) 1987-1990 Greenleaf Software	Inc.  All rights reserved.
 *
 * MODIFICATIONS
 *
 */

#include <stdio.h>
#include "gm.h"
#include "gmsystem.h"

DEC	*MultiplyDecimalAndTruncate(pDst,pSrc1,pSrc2,nid)
DEC	*pDst;
DEC	*pSrc1,*pSrc2;
int	nid;
{
	register int	i;

	_MacStart(GM_DMULT);

	if ((nid<GM_MINID)||(nid>GM_MAXID))  {
		_MacErr(GM_INVALIDID);
		_MacRet(GM_NULL);
	}

	if (!MultiplyDecimal(pDst, pSrc1, pSrc2))
		_MacRet(GM_NULL);

	if (_MacIsDecZ(pDst))  {
		pDst->dc.id = nid;
		_MacRet(pDst);
	}

	i = _TruncateDec80Bit(pDst, pDst, nid);

/*  check if number can	fit into 64 bits (no shifting allowed) */
	if (!((pDst->dc.msd == 0)  && (pDst->dc.sl[3] <	 32768L)))
	      i	= GM_OVERFLOW;

	if (i != GM_SUCCESS)  {
		_MacErr(i);
		_MacRet(GM_NULL);
		}

	if (_MacIsDecZ(pDst))
		_MacErr(GM_UNDERFLOW);

	_MacRet(pDst);

}