- 根目录:
- arch
- parisc
- math-emu
- fcnvfu.c
/*
* Linux/PA-RISC Project (http://www.parisc-linux.org/)
*
* Floating-point emulation code
* Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
* BEGIN_DESC
*
* File:
* @(#) pa/spmath/fcnvfu.c $Revision: 1.1 $
*
* Purpose:
* Floating-point to Unsigned Fixed-point Converts
*
* External Interfaces:
* dbl_to_dbl_fcnvfu(srcptr,nullptr,dstptr,status)
* dbl_to_sgl_fcnvfu(srcptr,nullptr,dstptr,status)
* sgl_to_dbl_fcnvfu(srcptr,nullptr,dstptr,status)
* sgl_to_sgl_fcnvfu(srcptr,nullptr,dstptr,status)
*
* Internal Interfaces:
*
* Theory:
* <<please update with a overview of the operation of this file>>
*
* END_DESC
*/
#include "float.h"
#include "sgl_float.h"
#include "dbl_float.h"
#include "cnv_float.h"
/************************************************************************
* Floating-point to Unsigned Fixed-point Converts *
************************************************************************/
/*
* Single Floating-point to Single Unsigned Fixed
*/
/*ARGSUSED*/
int
sgl_to_sgl_fcnvfu(
sgl_floating_point *srcptr,
unsigned int *nullptr,
unsigned int *dstptr,
unsigned int *status)
{
register unsigned int src, result;
register int src_exponent;
register boolean inexact = FALSE;
src = *srcptr;
src_exponent = Sgl_exponent(src) - SGL_BIAS;
/*
* Test for overflow
*/
if (src_exponent > SGL_FX_MAX_EXP + 1) {
if (Sgl_isone_sign(src)) {
result = 0;
} else {
result = 0xffffffff;
}
if (Is_invalidtrap_enabled()) {
return(INVALIDEXCEPTION);
}
Set_invalidflag();
*dstptr = result;
return(NOEXCEPTION);
}
/*
* Generate result
*/
if (src_exponent >= 0) {
/*
* Check sign.
* If negative, trap unimplemented.
*/
if (Sgl_isone_sign(src)) {
result = 0;
if (Is_invalidtrap_enabled()) {
return(INVALIDEXCEPTION);
}
Set_invalidflag();
*dstptr = result;
return(NOEXCEPTION);
}
Sgl_clear_signexponent_set_hidden(src);
Suint_from_sgl_mantissa(src,src_exponent,result);
/* check for inexact */
if (Sgl_isinexact_to_unsigned(src,src_exponent)) {
inexact = TRUE;
/* round result */
switch (Rounding_mode()) {
case ROUNDPLUS:
result++;
break;
case ROUNDMINUS: /* never negative */
break;
case ROUNDNEAREST:
if (Sgl_isone_roundbit(src,src_exponent) &&
(Sgl_isone_stickybit(src,src_exponent) ||
(result & 1))) {
result++;
}
break;
}
}
} else {
result = 0;
/* check for inexact */
if (Sgl_isnotzero_exponentmantissa(src)) {
inexact = TRUE;
/* round result */
switch (Rounding_mode()) {
case ROUNDPLUS:
if (Sgl_iszero_sign(src)) {
result++;
}
break;
case ROUNDMINUS:
if (Sgl_isone_sign(src)) {
result = 0;
if (Is_invalidtrap_enabled()) {
return(INVALIDEXCEPTION);
}
Set_invalidflag();
inexact = FALSE;
}
break;
case ROUNDNEAREST:
if (src_exponent == -1 &&
Sgl_isnotzero_mantissa(src)) {
if (Sgl_isone_sign(src)) {
result = 0;
if (Is_invalidtrap_enabled()) {
return(INVALIDEXCEPTION);
}
Set_invalidflag();
inexact = FALSE;
}
else result++;
}
break;
}
}
}
*dstptr = result;
if (inexact) {
if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
else Set_inexactflag();
}
return(NOEXCEPTION);
}
/*
* Single Floating-point to Double Unsigned Fixed
*/
/*ARGSUSED*/
int
sgl_to_dbl_fcnvfu(
sgl_floating_point *srcptr,
unsigned int *nullptr,
dbl_unsigned *dstptr,
unsigned int *status)
{
register int src_exponent;
register unsigned int src, resultp1, resultp2;
register boolean inexact = FALSE;
src = *srcptr;
src_exponent = Sgl_exponent(src) - SGL_BIAS;
/*
* Test for overflow
*/
if (src_exponent > DBL_FX_MAX_EXP + 1) {
if (Sgl_isone_sign(src)) {
resultp1 = resultp2 = 0;
} else {
resultp1 = resultp2 = 0xffffffff;
}
if (Is_invalidtrap_enabled()) {
return(INVALIDEXCEPTION);
}
Set_invalidflag();
Duint_copytoptr(resultp1,resultp2,dstptr);
return(NOEXCEPTION);
}
/*
* Generate result
*/
if (src_exponent >= 0) {
/*
* Check sign.
* If negative, trap unimplemented.
*/
if (Sgl_isone_sign(src)) {
resultp1 = resultp2 = 0;
if (Is_invalidtrap_enabled()) {
return(INVALIDEXCEPTION);
}
Set_invalidflag();
Duint_copytoptr(resultp1,resultp2,dstptr);
return(NOEXCEPTION);
}
Sgl_clear_signexponent_set_hidden(src);
Duint_from_sgl_mantissa(src,src_exponent,resultp1,resultp2);
/* check for inexact */
if (Sgl_isinexact_to_unsigned(src,src_exponent)) {
inexact = TRUE;
/* round result */
switch (Rounding_mode()) {
case ROUNDPLUS:
Duint_increment(resultp1,resultp2);
break;
case ROUNDMINUS: /* never negative */
break;
case ROUNDNEAREST:
if (Sgl_isone_roundbit(src,src_exponent) &&
(Sgl_isone_stickybit(src,src_exponent) ||
Duint_isone_lowp2(resultp2))) {
Duint_increment(resultp1,resultp2);
}
break;
}
}
} else {
Duint_setzero(resultp1,resultp2);
/* check for inexact */
if (Sgl_isnotzero_exponentmantissa(src)) {
inexact = TRUE;
/* round result */
switch (Rounding_mode()) {
case ROUNDPLUS:
if (Sgl_iszero_sign(src)) {
Duint_increment(resultp1,resultp2);
}
break;
case ROUNDMINUS:
if (Sgl_isone_sign(src)) {
resultp1 = resultp2 = 0;
if (Is_invalidtrap_enabled()) {
return(INVALIDEXCEPTION);
}
Set_invalidflag();
inexact = FALSE;
}
break;
case ROUNDNEAREST:
if (src_exponent == -1 &&
Sgl_isnotzero_mantissa(src)) {
if (Sgl_isone_sign(src)) {
resultp1 = 0;
resultp2 = 0;
if (Is_invalidtrap_enabled()) {
return(INVALIDEXCEPTION);
}
Set_invalidflag();
inexact = FALSE;
}
else Duint_increment(resultp1,resultp2);
}
}
}
}
Duint_copytoptr(resultp1,resultp2,dstptr);
if (inexact) {
if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
else Set_inexactflag();
}
return(NOEXCEPTION);
}
/*
* Double Floating-point to Single Unsigned Fixed
*/
/*ARGSUSED*/
int
dbl_to_sgl_fcnvfu (dbl_floating_point * srcptr, unsigned int *nullptr,
unsigned int *dstptr, unsigned int *status)
{
register unsigned int srcp1, srcp2, result;
register int src_exponent;
register boolean inexact = FALSE;
Dbl_copyfromptr(srcptr,srcp1,srcp2);
src_exponent = Dbl_exponent(srcp1) - DBL_BIAS;
/*
* Test for overflow
*/
if (src_exponent > SGL_FX_MAX_EXP + 1) {
if (Dbl_isone_sign(srcp1)) {
result = 0;
} else {
result = 0xffffffff;
}
if (Is_invalidtrap_enabled()) {
return(INVALIDEXCEPTION);
}
Set_invalidflag();
*dstptr = result;
return(NOEXCEPTION);
}
/*
* Generate result
*/
if (src_exponent >= 0) {
/*
* Check sign.
* If negative, trap unimplemented.
*/
if (Dbl_isone_sign(srcp1)) {
result = 0;
if (Is_invalidtrap_enabled()) {
return(INVALIDEXCEPTION);
}
Set_invalidflag();
*dstptr = result;
return(NOEXCEPTION);
}
Dbl_clear_signexponent_set_hidden(srcp1);
Suint_from_dbl_mantissa(srcp1,srcp2,src_exponent,result);
/* check for inexact */
if (Dbl_isinexact_to_unsigned(srcp1,srcp2,src_exponent)) {
inexact = TRUE;
/* round result */
switch (Rounding_mode()) {
case ROUNDPLUS:
result++;
break;
case ROUNDMINUS: /* never negative */
break;
case ROUNDNEAREST:
if(Dbl_isone_roundbit(srcp1,srcp2,src_exponent) &&
(Dbl_isone_stickybit(srcp1,srcp2,src_exponent)||
result&1))
result++;
break;
}
/* check for overflow */
if (result == 0) {
result = 0xffffffff;
if (Is_invalidtrap_enabled()) {
return(INVALIDEXCEPTION);
}
Set_invalidflag();
*dstptr = result;
return(NOEXCEPTION);
}
}
} else {
result = 0;
/* check for inexact */
if (Dbl_isnotzero_exponentmantissa(srcp1,srcp2)) {
inexact = TRUE;
/* round result */
switch (Rounding_mode()) {
case ROUNDPLUS:
if (Dbl_iszero_sign(srcp1)) result++;
break;
case ROUNDMINUS:
if (Dbl_isone_sign(srcp1)) {
result = 0;
if (Is_invalidtrap_enabled()) {
return(INVALIDEXCEPTION);
}
Set_invalidflag();
inexact = FALSE;
}
break;
case ROUNDNEAREST:
if (src_exponent == -1 &&
Dbl_isnotzero_mantissa(srcp1,srcp2))
if (Dbl_isone_sign(srcp1)) {
result = 0;
if (Is_invalidtrap_enabled()) {
return(INVALIDEXCEPTION);
}
Set_invalidflag();
inexact = FALSE;
}
else result++;
}
}
}
*dstptr = result;
if (inexact) {
if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
else Set_inexactflag();
}
return(NOEXCEPTION);
}
/*
* Double Floating-point to Double Unsigned Fixed
*/
/*ARGSUSED*/
int
dbl_to_dbl_fcnvfu (dbl_floating_point * srcptr, unsigned int *nullptr,
dbl_unsigned * dstptr, unsigned int *status)
{
register int src_exponent;
register unsigned int srcp1, srcp2, resultp1, resultp2;
register boolean inexact = FALSE;
Dbl_copyfromptr(srcptr,srcp1,srcp2);
src_exponent = Dbl_exponent(srcp1) - DBL_BIAS;
/*
* Test for overflow
*/
if (src_exponent > DBL_FX_MAX_EXP + 1) {
if (Dbl_isone_sign(srcp1)) {
resultp1 = resultp2 = 0;
} else {
resultp1 = resultp2 = 0xffffffff;
}
if (Is_invalidtrap_enabled()) {
return(INVALIDEXCEPTION);
}
Set_invalidflag();
Duint_copytoptr(resultp1,resultp2,dstptr);
return(NOEXCEPTION);
}
/*
* Generate result
*/
if (src_exponent >= 0) {
/*
* Check sign.
* If negative, trap unimplemented.
*/
if (Dbl_isone_sign(srcp1)) {
resultp1 = resultp2 = 0;
if (Is_invalidtrap_enabled()) {
return(INVALIDEXCEPTION);
}
Set_invalidflag();
Duint_copytoptr(resultp1,resultp2,dstptr);
return(NOEXCEPTION);
}
Dbl_clear_signexponent_set_hidden(srcp1);
Duint_from_dbl_mantissa(srcp1,srcp2,src_exponent,resultp1,
resultp2);
/* check for inexact */
if (Dbl_isinexact_to_unsigned(srcp1,srcp2,src_exponent)) {
inexact = TRUE;
/* round result */
switch (Rounding_mode()) {
case ROUNDPLUS:
Duint_increment(resultp1,resultp2);
break;
case ROUNDMINUS: /* never negative */
break;
case ROUNDNEAREST:
if(Dbl_isone_roundbit(srcp1,srcp2,src_exponent))
if(Dbl_isone_stickybit(srcp1,srcp2,src_exponent) ||
Duint_isone_lowp2(resultp2))
Duint_increment(resultp1,resultp2);
}
}
} else {
Duint_setzero(resultp1,resultp2);
/* check for inexact */
if (Dbl_isnotzero_exponentmantissa(srcp1,srcp2)) {
inexact = TRUE;
/* round result */
switch (Rounding_mode()) {
case ROUNDPLUS:
if (Dbl_iszero_sign(srcp1)) {
Duint_increment(resultp1,resultp2);
}
break;
case ROUNDMINUS:
if (Dbl_isone_sign(srcp1)) {
resultp1 = resultp2 = 0;
if (Is_invalidtrap_enabled()) {
return(INVALIDEXCEPTION);
}
Set_invalidflag();
inexact = FALSE;
}
break;
case ROUNDNEAREST:
if (src_exponent == -1 &&
Dbl_isnotzero_mantissa(srcp1,srcp2))
if (Dbl_iszero_sign(srcp1)) {
Duint_increment(resultp1,resultp2);
} else {
resultp1 = 0;
resultp2 = 0;
if (Is_invalidtrap_enabled()) {
return(INVALIDEXCEPTION);
}
Set_invalidflag();
inexact = FALSE;
}
}
}
}
Duint_copytoptr(resultp1,resultp2,dstptr);
if (inexact) {
if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
else Set_inexactflag();
}
return(NOEXCEPTION);
}