- 根目录:
- arch
- parisc
- math-emu
- fcnvuf.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/fcnvuf.c $Revision: 1.1 $
*
* Purpose:
* Fixed point to Floating-point Converts
*
* External Interfaces:
* dbl_to_dbl_fcnvuf(srcptr,nullptr,dstptr,status)
* dbl_to_sgl_fcnvuf(srcptr,nullptr,dstptr,status)
* sgl_to_dbl_fcnvuf(srcptr,nullptr,dstptr,status)
* sgl_to_sgl_fcnvuf(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"
/************************************************************************
* Fixed point to Floating-point Converts *
************************************************************************/
/*
* Convert Single Unsigned Fixed to Single Floating-point format
*/
int
sgl_to_sgl_fcnvuf(
unsigned int *srcptr,
unsigned int *nullptr,
sgl_floating_point *dstptr,
unsigned int *status)
{
register unsigned int src, result = 0;
register int dst_exponent;
src = *srcptr;
/* Check for zero */
if (src == 0) {
Sgl_setzero(result);
*dstptr = result;
return(NOEXCEPTION);
}
/*
* Generate exponent and normalized mantissa
*/
dst_exponent = 16; /* initialize for normalization */
/*
* Check word for most significant bit set. Returns
* a value in dst_exponent indicating the bit position,
* between -1 and 30.
*/
Find_ms_one_bit(src,dst_exponent);
/* left justify source, with msb at bit position 0 */
src <<= dst_exponent+1;
Sgl_set_mantissa(result, src >> SGL_EXP_LENGTH);
Sgl_set_exponent(result, 30+SGL_BIAS - dst_exponent);
/* check for inexact */
if (Suint_isinexact_to_sgl(src)) {
switch (Rounding_mode()) {
case ROUNDPLUS:
Sgl_increment(result);
break;
case ROUNDMINUS: /* never negative */
break;
case ROUNDNEAREST:
Sgl_roundnearest_from_suint(src,result);
break;
}
if (Is_inexacttrap_enabled()) {
*dstptr = result;
return(INEXACTEXCEPTION);
}
else Set_inexactflag();
}
*dstptr = result;
return(NOEXCEPTION);
}
/*
* Single Unsigned Fixed to Double Floating-point
*/
int
sgl_to_dbl_fcnvuf(
unsigned int *srcptr,
unsigned int *nullptr,
dbl_floating_point *dstptr,
unsigned int *status)
{
register int dst_exponent;
register unsigned int src, resultp1 = 0, resultp2 = 0;
src = *srcptr;
/* Check for zero */
if (src == 0) {
Dbl_setzero(resultp1,resultp2);
Dbl_copytoptr(resultp1,resultp2,dstptr);
return(NOEXCEPTION);
}
/*
* Generate exponent and normalized mantissa
*/
dst_exponent = 16; /* initialize for normalization */
/*
* Check word for most significant bit set. Returns
* a value in dst_exponent indicating the bit position,
* between -1 and 30.
*/
Find_ms_one_bit(src,dst_exponent);
/* left justify source, with msb at bit position 0 */
src <<= dst_exponent+1;
Dbl_set_mantissap1(resultp1, src >> DBL_EXP_LENGTH);
Dbl_set_mantissap2(resultp2, src << (32-DBL_EXP_LENGTH));
Dbl_set_exponent(resultp1, (30+DBL_BIAS) - dst_exponent);
Dbl_copytoptr(resultp1,resultp2,dstptr);
return(NOEXCEPTION);
}
/*
* Double Unsigned Fixed to Single Floating-point
*/
int
dbl_to_sgl_fcnvuf(
dbl_unsigned *srcptr,
unsigned int *nullptr,
sgl_floating_point *dstptr,
unsigned int *status)
{
int dst_exponent;
unsigned int srcp1, srcp2, result = 0;
Duint_copyfromptr(srcptr,srcp1,srcp2);
/* Check for zero */
if (srcp1 == 0 && srcp2 == 0) {
Sgl_setzero(result);
*dstptr = result;
return(NOEXCEPTION);
}
/*
* Generate exponent and normalized mantissa
*/
dst_exponent = 16; /* initialize for normalization */
if (srcp1 == 0) {
/*
* Check word for most significant bit set. Returns
* a value in dst_exponent indicating the bit position,
* between -1 and 30.
*/
Find_ms_one_bit(srcp2,dst_exponent);
/* left justify source, with msb at bit position 0 */
srcp1 = srcp2 << dst_exponent+1;
srcp2 = 0;
/*
* since msb set is in second word, need to
* adjust bit position count
*/
dst_exponent += 32;
}
else {
/*
* Check word for most significant bit set. Returns
* a value in dst_exponent indicating the bit position,
* between -1 and 30.
*
*/
Find_ms_one_bit(srcp1,dst_exponent);
/* left justify source, with msb at bit position 0 */
if (dst_exponent >= 0) {
Variable_shift_double(srcp1,srcp2,(31-dst_exponent),
srcp1);
srcp2 <<= dst_exponent+1;
}
}
Sgl_set_mantissa(result, srcp1 >> SGL_EXP_LENGTH);
Sgl_set_exponent(result, (62+SGL_BIAS) - dst_exponent);
/* check for inexact */
if (Duint_isinexact_to_sgl(srcp1,srcp2)) {
switch (Rounding_mode()) {
case ROUNDPLUS:
Sgl_increment(result);
break;
case ROUNDMINUS: /* never negative */
break;
case ROUNDNEAREST:
Sgl_roundnearest_from_duint(srcp1,srcp2,result);
break;
}
if (Is_inexacttrap_enabled()) {
*dstptr = result;
return(INEXACTEXCEPTION);
}
else Set_inexactflag();
}
*dstptr = result;
return(NOEXCEPTION);
}
/*
* Double Unsigned Fixed to Double Floating-point
*/
int
dbl_to_dbl_fcnvuf(
dbl_unsigned *srcptr,
unsigned int *nullptr,
dbl_floating_point *dstptr,
unsigned int *status)
{
register int dst_exponent;
register unsigned int srcp1, srcp2, resultp1 = 0, resultp2 = 0;
Duint_copyfromptr(srcptr,srcp1,srcp2);
/* Check for zero */
if (srcp1 == 0 && srcp2 ==0) {
Dbl_setzero(resultp1,resultp2);
Dbl_copytoptr(resultp1,resultp2,dstptr);
return(NOEXCEPTION);
}
/*
* Generate exponent and normalized mantissa
*/
dst_exponent = 16; /* initialize for normalization */
if (srcp1 == 0) {
/*
* Check word for most significant bit set. Returns
* a value in dst_exponent indicating the bit position,
* between -1 and 30.
*/
Find_ms_one_bit(srcp2,dst_exponent);
/* left justify source, with msb at bit position 0 */
srcp1 = srcp2 << dst_exponent+1;
srcp2 = 0;
/*
* since msb set is in second word, need to
* adjust bit position count
*/
dst_exponent += 32;
}
else {
/*
* Check word for most significant bit set. Returns
* a value in dst_exponent indicating the bit position,
* between -1 and 30.
*/
Find_ms_one_bit(srcp1,dst_exponent);
/* left justify source, with msb at bit position 0 */
if (dst_exponent >= 0) {
Variable_shift_double(srcp1,srcp2,(31-dst_exponent),
srcp1);
srcp2 <<= dst_exponent+1;
}
}
Dbl_set_mantissap1(resultp1, srcp1 >> DBL_EXP_LENGTH);
Shiftdouble(srcp1,srcp2,DBL_EXP_LENGTH,resultp2);
Dbl_set_exponent(resultp1, (62+DBL_BIAS) - dst_exponent);
/* check for inexact */
if (Duint_isinexact_to_dbl(srcp2)) {
switch (Rounding_mode()) {
case ROUNDPLUS:
Dbl_increment(resultp1,resultp2);
break;
case ROUNDMINUS: /* never negative */
break;
case ROUNDNEAREST:
Dbl_roundnearest_from_duint(srcp2,resultp1,
resultp2);
break;
}
if (Is_inexacttrap_enabled()) {
Dbl_copytoptr(resultp1,resultp2,dstptr);
return(INEXACTEXCEPTION);
}
else Set_inexactflag();
}
Dbl_copytoptr(resultp1,resultp2,dstptr);
return(NOEXCEPTION);
}