/*	$OpenBSD: fcnvff.c,v 1.7 2003/04/10 17:27:58 mickey Exp $	*/
/*
  (c) Copyright 1986 HEWLETT-PACKARD COMPANY
  To anyone who acknowledges that this file is provided "AS IS"
  without any express or implied warranty:
      permission to use, copy, modify, and distribute this file
  for any purpose is hereby granted without fee, provided that
  the above copyright notice and this notice appears in all
  copies, and that the name of Hewlett-Packard Company not be
  used in advertising or publicity pertaining to distribution
  of the software without specific, written prior permission.
  Hewlett-Packard Company makes no representations about the
  suitability of this software for any purpose.
*/
/* @(#)fcnvff.c: Revision: 2.8.88.1 Date: 93/12/07 15:06:09 */

#include "float.h"
#include "sgl_float.h"
#include "dbl_float.h"
#include "cnv_float.h"

/*
 *  Single Floating-point to Double Floating-point
 */
/*ARGSUSED*/
int
sgl_to_dbl_fcnvff(srcptr, null, dstptr, status)
	sgl_floating_point *srcptr, *null;
	dbl_floating_point *dstptr;
	unsigned int *status;
{
	register unsigned int src, resultp1, resultp2;
	register int src_exponent;

	src = *srcptr;
	src_exponent = Sgl_exponent(src);
	Dbl_allp1(resultp1) = Sgl_all(src);  /* set sign of result */
	/*
	 * Test for NaN or infinity
	 */
	if (src_exponent == SGL_INFINITY_EXPONENT) {
		/*
		 * determine if NaN or infinity
		 */
		if (Sgl_iszero_mantissa(src)) {
			/*
			 * is infinity; want to return double infinity
			 */
			Dbl_setinfinity_exponentmantissa(resultp1,resultp2);
			Dbl_copytoptr(resultp1,resultp2,dstptr);
			return(NOEXCEPTION);
		}
		else {
			/*
			 * is NaN; signaling or quiet?
			 */
			if (Sgl_isone_signaling(src)) {
				/* trap if INVALIDTRAP enabled */
				if (Is_invalidtrap_enabled())
					return(INVALIDEXCEPTION);
				/* make NaN quiet */
				else {
					Set_invalidflag();
					Sgl_set_quiet(src);
				}
			}
			/*
			 * NaN is quiet, return as double NaN
			 */
			Dbl_setinfinity_exponent(resultp1);
			Sgl_to_dbl_mantissa(src,resultp1,resultp2);
			Dbl_copytoptr(resultp1,resultp2,dstptr);
			return(NOEXCEPTION);
		}
	}
	/*
	 * Test for zero or denormalized
	 */
	if (src_exponent == 0) {
		/*
		 * determine if zero or denormalized
		 */
		if (Sgl_isnotzero_mantissa(src)) {
			/*
			 * is denormalized; want to normalize
			 */
			Sgl_clear_signexponent(src);
			Sgl_leftshiftby1(src);
			Sgl_normalize(src,src_exponent);
			Sgl_to_dbl_exponent(src_exponent,resultp1);
			Sgl_to_dbl_mantissa(src,resultp1,resultp2);
		}
		else {
			Dbl_setzero_exponentmantissa(resultp1,resultp2);
		}
		Dbl_copytoptr(resultp1,resultp2,dstptr);
		return(NOEXCEPTION);
	}
	/*
	 * No special cases, just complete the conversion
	 */
	Sgl_to_dbl_exponent(src_exponent, resultp1);
	Sgl_to_dbl_mantissa(Sgl_mantissa(src), resultp1,resultp2);
	Dbl_copytoptr(resultp1,resultp2,dstptr);
	return(NOEXCEPTION);
}

/*
 *  Double Floating-point to Single Floating-point
 */
/*ARGSUSED*/
int
dbl_to_sgl_fcnvff(srcptr, null, dstptr, status)
	dbl_floating_point *srcptr, *null;
	sgl_floating_point *dstptr;
	unsigned int *status;
{
	register unsigned int srcp1, srcp2, result;
	register int src_exponent, dest_exponent, dest_mantissa;
	register int inexact = FALSE, guardbit = FALSE, stickybit = FALSE;
	register int lsb_odd = FALSE;
	int is_tiny;

	Dbl_copyfromptr(srcptr,srcp1,srcp2);
	src_exponent = Dbl_exponent(srcp1);
	Sgl_all(result) = Dbl_allp1(srcp1);  /* set sign of result */
	/*
	 * Test for NaN or infinity
	 */
	if (src_exponent == DBL_INFINITY_EXPONENT) {
		/*
		 * determine if NaN or infinity
		 */
		if (Dbl_iszero_mantissa(srcp1,srcp2)) {
			/*
			 * is infinity; want to return single infinity
			 */
			Sgl_setinfinity_exponentmantissa(result);
			*dstptr = result;
			return(NOEXCEPTION);
		}
		/*
		 * is NaN; signaling or quiet?
		 */
		if (Dbl_isone_signaling(srcp1)) {
			/* trap if INVALIDTRAP enabled */
			if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
			else {
				Set_invalidflag();
				/* make NaN quiet */
				Dbl_set_quiet(srcp1);
			}
		}
		/*
		 * NaN is quiet, return as single NaN
		 */
		Sgl_setinfinity_exponent(result);
		Sgl_set_mantissa(result,Dallp1(srcp1)<<3 | Dallp2(srcp2)>>29);
		if (Sgl_iszero_mantissa(result)) Sgl_set_quiet(result);
		*dstptr = result;
		return(NOEXCEPTION);
	}
	/*
	 * Generate result
	 */
	Dbl_to_sgl_exponent(src_exponent,dest_exponent);
	if (dest_exponent > 0) {
		Dbl_to_sgl_mantissa(srcp1,srcp2,dest_mantissa,inexact,guardbit,
		stickybit,lsb_odd);
	}
	else {
		if (Dbl_iszero_exponentmantissa(srcp1,srcp2)){
			Sgl_setzero_exponentmantissa(result);
			*dstptr = result;
			return(NOEXCEPTION);
		}
		if (Is_underflowtrap_enabled()) {
			Dbl_to_sgl_mantissa(srcp1,srcp2,dest_mantissa,inexact,
			guardbit,stickybit,lsb_odd);
		}
		else {
			/* compute result, determine inexact info,
			 * and set Underflowflag if appropriate
			 */
			Dbl_to_sgl_denormalized(srcp1,srcp2,dest_exponent,
			dest_mantissa,inexact,guardbit,stickybit,lsb_odd,
			is_tiny);
		}
	}
	/*
	 * Now round result if not exact
	 */
	if (inexact) {
		switch (Rounding_mode()) {
			case ROUNDPLUS:
				if (Sgl_iszero_sign(result)) dest_mantissa++;
				break;
			case ROUNDMINUS:
				if (Sgl_isone_sign(result)) dest_mantissa++;
				break;
			case ROUNDNEAREST:
				if (guardbit) {
				   if (stickybit || lsb_odd) dest_mantissa++;
				   }
		}
	}
	Sgl_set_exponentmantissa(result,dest_mantissa);

	/*
	 * check for mantissa overflow after rounding
	 */
	if ((dest_exponent>0 || Is_underflowtrap_enabled()) &&
	    Sgl_isone_hidden(result)) dest_exponent++;

	/*
	 * Test for overflow
	 */
	if (dest_exponent >= SGL_INFINITY_EXPONENT) {
		/* trap if OVERFLOWTRAP enabled */
		if (Is_overflowtrap_enabled()) {
			/*
			 * Check for gross overflow
			 */
			if (dest_exponent >= SGL_INFINITY_EXPONENT+SGL_WRAP)
				return(UNIMPLEMENTEDEXCEPTION);

			/*
			 * Adjust bias of result
			 */
			Sgl_setwrapped_exponent(result,dest_exponent,ovfl);
			*dstptr = result;
			if (inexact) {
			    if (Is_inexacttrap_enabled())
				return(OVERFLOWEXCEPTION|INEXACTEXCEPTION);
			    else
				Set_inexactflag();
			}
			return(OVERFLOWEXCEPTION);
		}
		Set_overflowflag();
		inexact = TRUE;
		/* set result to infinity or largest number */
		Sgl_setoverflow(result);
	}
	/*
	 * Test for underflow
	 */
	else if (dest_exponent <= 0) {
		/* trap if UNDERFLOWTRAP enabled */
		if (Is_underflowtrap_enabled()) {
			/*
			 * Check for gross underflow
			 */
			if (dest_exponent <= -(SGL_WRAP))
				return(UNIMPLEMENTEDEXCEPTION);
			/*
			 * Adjust bias of result
			 */
			Sgl_setwrapped_exponent(result,dest_exponent,unfl);
			*dstptr = result;
			if (inexact) {
			    if (Is_inexacttrap_enabled())
				return(UNDERFLOWEXCEPTION|INEXACTEXCEPTION);
			    else
				Set_inexactflag();
			}
			return(UNDERFLOWEXCEPTION);
		}
		 /*
		  * result is denormalized or signed zero
		  */
	       if (inexact && is_tiny) Set_underflowflag();

	}
	else Sgl_set_exponent(result,dest_exponent);
	*dstptr = result;
	/*
	 * Trap if inexact trap is enabled
	 */
	if (inexact) {
		if (Is_inexacttrap_enabled())
			return(INEXACTEXCEPTION);
		else
			Set_inexactflag();
	}
	return(NOEXCEPTION);
}