mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-18 09:44:18 +08:00
1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
401 lines
12 KiB
C
401 lines
12 KiB
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/dfdiv.c $Revision: 1.1 $
|
|
*
|
|
* Purpose:
|
|
* Double Precision Floating-point Divide
|
|
*
|
|
* External Interfaces:
|
|
* dbl_fdiv(srcptr1,srcptr2,dstptr,status)
|
|
*
|
|
* Internal Interfaces:
|
|
*
|
|
* Theory:
|
|
* <<please update with a overview of the operation of this file>>
|
|
*
|
|
* END_DESC
|
|
*/
|
|
|
|
|
|
#include "float.h"
|
|
#include "dbl_float.h"
|
|
|
|
/*
|
|
* Double Precision Floating-point Divide
|
|
*/
|
|
|
|
int
|
|
dbl_fdiv (dbl_floating_point * srcptr1, dbl_floating_point * srcptr2,
|
|
dbl_floating_point * dstptr, unsigned int *status)
|
|
{
|
|
register unsigned int opnd1p1, opnd1p2, opnd2p1, opnd2p2;
|
|
register unsigned int opnd3p1, opnd3p2, resultp1, resultp2;
|
|
register int dest_exponent, count;
|
|
register boolean inexact = FALSE, guardbit = FALSE, stickybit = FALSE;
|
|
boolean is_tiny;
|
|
|
|
Dbl_copyfromptr(srcptr1,opnd1p1,opnd1p2);
|
|
Dbl_copyfromptr(srcptr2,opnd2p1,opnd2p2);
|
|
/*
|
|
* set sign bit of result
|
|
*/
|
|
if (Dbl_sign(opnd1p1) ^ Dbl_sign(opnd2p1))
|
|
Dbl_setnegativezerop1(resultp1);
|
|
else Dbl_setzerop1(resultp1);
|
|
/*
|
|
* check first operand for NaN's or infinity
|
|
*/
|
|
if (Dbl_isinfinity_exponent(opnd1p1)) {
|
|
if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) {
|
|
if (Dbl_isnotnan(opnd2p1,opnd2p2)) {
|
|
if (Dbl_isinfinity(opnd2p1,opnd2p2)) {
|
|
/*
|
|
* invalid since both operands
|
|
* are infinity
|
|
*/
|
|
if (Is_invalidtrap_enabled())
|
|
return(INVALIDEXCEPTION);
|
|
Set_invalidflag();
|
|
Dbl_makequietnan(resultp1,resultp2);
|
|
Dbl_copytoptr(resultp1,resultp2,dstptr);
|
|
return(NOEXCEPTION);
|
|
}
|
|
/*
|
|
* return infinity
|
|
*/
|
|
Dbl_setinfinity_exponentmantissa(resultp1,resultp2);
|
|
Dbl_copytoptr(resultp1,resultp2,dstptr);
|
|
return(NOEXCEPTION);
|
|
}
|
|
}
|
|
else {
|
|
/*
|
|
* is NaN; signaling or quiet?
|
|
*/
|
|
if (Dbl_isone_signaling(opnd1p1)) {
|
|
/* trap if INVALIDTRAP enabled */
|
|
if (Is_invalidtrap_enabled())
|
|
return(INVALIDEXCEPTION);
|
|
/* make NaN quiet */
|
|
Set_invalidflag();
|
|
Dbl_set_quiet(opnd1p1);
|
|
}
|
|
/*
|
|
* is second operand a signaling NaN?
|
|
*/
|
|
else if (Dbl_is_signalingnan(opnd2p1)) {
|
|
/* trap if INVALIDTRAP enabled */
|
|
if (Is_invalidtrap_enabled())
|
|
return(INVALIDEXCEPTION);
|
|
/* make NaN quiet */
|
|
Set_invalidflag();
|
|
Dbl_set_quiet(opnd2p1);
|
|
Dbl_copytoptr(opnd2p1,opnd2p2,dstptr);
|
|
return(NOEXCEPTION);
|
|
}
|
|
/*
|
|
* return quiet NaN
|
|
*/
|
|
Dbl_copytoptr(opnd1p1,opnd1p2,dstptr);
|
|
return(NOEXCEPTION);
|
|
}
|
|
}
|
|
/*
|
|
* check second operand for NaN's or infinity
|
|
*/
|
|
if (Dbl_isinfinity_exponent(opnd2p1)) {
|
|
if (Dbl_iszero_mantissa(opnd2p1,opnd2p2)) {
|
|
/*
|
|
* return zero
|
|
*/
|
|
Dbl_setzero_exponentmantissa(resultp1,resultp2);
|
|
Dbl_copytoptr(resultp1,resultp2,dstptr);
|
|
return(NOEXCEPTION);
|
|
}
|
|
/*
|
|
* is NaN; signaling or quiet?
|
|
*/
|
|
if (Dbl_isone_signaling(opnd2p1)) {
|
|
/* trap if INVALIDTRAP enabled */
|
|
if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
|
|
/* make NaN quiet */
|
|
Set_invalidflag();
|
|
Dbl_set_quiet(opnd2p1);
|
|
}
|
|
/*
|
|
* return quiet NaN
|
|
*/
|
|
Dbl_copytoptr(opnd2p1,opnd2p2,dstptr);
|
|
return(NOEXCEPTION);
|
|
}
|
|
/*
|
|
* check for division by zero
|
|
*/
|
|
if (Dbl_iszero_exponentmantissa(opnd2p1,opnd2p2)) {
|
|
if (Dbl_iszero_exponentmantissa(opnd1p1,opnd1p2)) {
|
|
/* invalid since both operands are zero */
|
|
if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
|
|
Set_invalidflag();
|
|
Dbl_makequietnan(resultp1,resultp2);
|
|
Dbl_copytoptr(resultp1,resultp2,dstptr);
|
|
return(NOEXCEPTION);
|
|
}
|
|
if (Is_divisionbyzerotrap_enabled())
|
|
return(DIVISIONBYZEROEXCEPTION);
|
|
Set_divisionbyzeroflag();
|
|
Dbl_setinfinity_exponentmantissa(resultp1,resultp2);
|
|
Dbl_copytoptr(resultp1,resultp2,dstptr);
|
|
return(NOEXCEPTION);
|
|
}
|
|
/*
|
|
* Generate exponent
|
|
*/
|
|
dest_exponent = Dbl_exponent(opnd1p1) - Dbl_exponent(opnd2p1) + DBL_BIAS;
|
|
|
|
/*
|
|
* Generate mantissa
|
|
*/
|
|
if (Dbl_isnotzero_exponent(opnd1p1)) {
|
|
/* set hidden bit */
|
|
Dbl_clear_signexponent_set_hidden(opnd1p1);
|
|
}
|
|
else {
|
|
/* check for zero */
|
|
if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) {
|
|
Dbl_setzero_exponentmantissa(resultp1,resultp2);
|
|
Dbl_copytoptr(resultp1,resultp2,dstptr);
|
|
return(NOEXCEPTION);
|
|
}
|
|
/* is denormalized, want to normalize */
|
|
Dbl_clear_signexponent(opnd1p1);
|
|
Dbl_leftshiftby1(opnd1p1,opnd1p2);
|
|
Dbl_normalize(opnd1p1,opnd1p2,dest_exponent);
|
|
}
|
|
/* opnd2 needs to have hidden bit set with msb in hidden bit */
|
|
if (Dbl_isnotzero_exponent(opnd2p1)) {
|
|
Dbl_clear_signexponent_set_hidden(opnd2p1);
|
|
}
|
|
else {
|
|
/* is denormalized; want to normalize */
|
|
Dbl_clear_signexponent(opnd2p1);
|
|
Dbl_leftshiftby1(opnd2p1,opnd2p2);
|
|
while (Dbl_iszero_hiddenhigh7mantissa(opnd2p1)) {
|
|
dest_exponent+=8;
|
|
Dbl_leftshiftby8(opnd2p1,opnd2p2);
|
|
}
|
|
if (Dbl_iszero_hiddenhigh3mantissa(opnd2p1)) {
|
|
dest_exponent+=4;
|
|
Dbl_leftshiftby4(opnd2p1,opnd2p2);
|
|
}
|
|
while (Dbl_iszero_hidden(opnd2p1)) {
|
|
dest_exponent++;
|
|
Dbl_leftshiftby1(opnd2p1,opnd2p2);
|
|
}
|
|
}
|
|
|
|
/* Divide the source mantissas */
|
|
|
|
/*
|
|
* A non-restoring divide algorithm is used.
|
|
*/
|
|
Twoword_subtract(opnd1p1,opnd1p2,opnd2p1,opnd2p2);
|
|
Dbl_setzero(opnd3p1,opnd3p2);
|
|
for (count=1; count <= DBL_P && (opnd1p1 || opnd1p2); count++) {
|
|
Dbl_leftshiftby1(opnd1p1,opnd1p2);
|
|
Dbl_leftshiftby1(opnd3p1,opnd3p2);
|
|
if (Dbl_iszero_sign(opnd1p1)) {
|
|
Dbl_setone_lowmantissap2(opnd3p2);
|
|
Twoword_subtract(opnd1p1,opnd1p2,opnd2p1,opnd2p2);
|
|
}
|
|
else {
|
|
Twoword_add(opnd1p1, opnd1p2, opnd2p1, opnd2p2);
|
|
}
|
|
}
|
|
if (count <= DBL_P) {
|
|
Dbl_leftshiftby1(opnd3p1,opnd3p2);
|
|
Dbl_setone_lowmantissap2(opnd3p2);
|
|
Dbl_leftshift(opnd3p1,opnd3p2,(DBL_P-count));
|
|
if (Dbl_iszero_hidden(opnd3p1)) {
|
|
Dbl_leftshiftby1(opnd3p1,opnd3p2);
|
|
dest_exponent--;
|
|
}
|
|
}
|
|
else {
|
|
if (Dbl_iszero_hidden(opnd3p1)) {
|
|
/* need to get one more bit of result */
|
|
Dbl_leftshiftby1(opnd1p1,opnd1p2);
|
|
Dbl_leftshiftby1(opnd3p1,opnd3p2);
|
|
if (Dbl_iszero_sign(opnd1p1)) {
|
|
Dbl_setone_lowmantissap2(opnd3p2);
|
|
Twoword_subtract(opnd1p1,opnd1p2,opnd2p1,opnd2p2);
|
|
}
|
|
else {
|
|
Twoword_add(opnd1p1,opnd1p2,opnd2p1,opnd2p2);
|
|
}
|
|
dest_exponent--;
|
|
}
|
|
if (Dbl_iszero_sign(opnd1p1)) guardbit = TRUE;
|
|
stickybit = Dbl_allp1(opnd1p1) || Dbl_allp2(opnd1p2);
|
|
}
|
|
inexact = guardbit | stickybit;
|
|
|
|
/*
|
|
* round result
|
|
*/
|
|
if (inexact && (dest_exponent > 0 || Is_underflowtrap_enabled())) {
|
|
Dbl_clear_signexponent(opnd3p1);
|
|
switch (Rounding_mode()) {
|
|
case ROUNDPLUS:
|
|
if (Dbl_iszero_sign(resultp1))
|
|
Dbl_increment(opnd3p1,opnd3p2);
|
|
break;
|
|
case ROUNDMINUS:
|
|
if (Dbl_isone_sign(resultp1))
|
|
Dbl_increment(opnd3p1,opnd3p2);
|
|
break;
|
|
case ROUNDNEAREST:
|
|
if (guardbit && (stickybit ||
|
|
Dbl_isone_lowmantissap2(opnd3p2))) {
|
|
Dbl_increment(opnd3p1,opnd3p2);
|
|
}
|
|
}
|
|
if (Dbl_isone_hidden(opnd3p1)) dest_exponent++;
|
|
}
|
|
Dbl_set_mantissa(resultp1,resultp2,opnd3p1,opnd3p2);
|
|
|
|
/*
|
|
* Test for overflow
|
|
*/
|
|
if (dest_exponent >= DBL_INFINITY_EXPONENT) {
|
|
/* trap if OVERFLOWTRAP enabled */
|
|
if (Is_overflowtrap_enabled()) {
|
|
/*
|
|
* Adjust bias of result
|
|
*/
|
|
Dbl_setwrapped_exponent(resultp1,dest_exponent,ovfl);
|
|
Dbl_copytoptr(resultp1,resultp2,dstptr);
|
|
if (inexact)
|
|
if (Is_inexacttrap_enabled())
|
|
return(OVERFLOWEXCEPTION | INEXACTEXCEPTION);
|
|
else Set_inexactflag();
|
|
return(OVERFLOWEXCEPTION);
|
|
}
|
|
Set_overflowflag();
|
|
/* set result to infinity or largest number */
|
|
Dbl_setoverflow(resultp1,resultp2);
|
|
inexact = TRUE;
|
|
}
|
|
/*
|
|
* Test for underflow
|
|
*/
|
|
else if (dest_exponent <= 0) {
|
|
/* trap if UNDERFLOWTRAP enabled */
|
|
if (Is_underflowtrap_enabled()) {
|
|
/*
|
|
* Adjust bias of result
|
|
*/
|
|
Dbl_setwrapped_exponent(resultp1,dest_exponent,unfl);
|
|
Dbl_copytoptr(resultp1,resultp2,dstptr);
|
|
if (inexact)
|
|
if (Is_inexacttrap_enabled())
|
|
return(UNDERFLOWEXCEPTION | INEXACTEXCEPTION);
|
|
else Set_inexactflag();
|
|
return(UNDERFLOWEXCEPTION);
|
|
}
|
|
|
|
/* Determine if should set underflow flag */
|
|
is_tiny = TRUE;
|
|
if (dest_exponent == 0 && inexact) {
|
|
switch (Rounding_mode()) {
|
|
case ROUNDPLUS:
|
|
if (Dbl_iszero_sign(resultp1)) {
|
|
Dbl_increment(opnd3p1,opnd3p2);
|
|
if (Dbl_isone_hiddenoverflow(opnd3p1))
|
|
is_tiny = FALSE;
|
|
Dbl_decrement(opnd3p1,opnd3p2);
|
|
}
|
|
break;
|
|
case ROUNDMINUS:
|
|
if (Dbl_isone_sign(resultp1)) {
|
|
Dbl_increment(opnd3p1,opnd3p2);
|
|
if (Dbl_isone_hiddenoverflow(opnd3p1))
|
|
is_tiny = FALSE;
|
|
Dbl_decrement(opnd3p1,opnd3p2);
|
|
}
|
|
break;
|
|
case ROUNDNEAREST:
|
|
if (guardbit && (stickybit ||
|
|
Dbl_isone_lowmantissap2(opnd3p2))) {
|
|
Dbl_increment(opnd3p1,opnd3p2);
|
|
if (Dbl_isone_hiddenoverflow(opnd3p1))
|
|
is_tiny = FALSE;
|
|
Dbl_decrement(opnd3p1,opnd3p2);
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* denormalize result or set to signed zero
|
|
*/
|
|
stickybit = inexact;
|
|
Dbl_denormalize(opnd3p1,opnd3p2,dest_exponent,guardbit,
|
|
stickybit,inexact);
|
|
|
|
/* return rounded number */
|
|
if (inexact) {
|
|
switch (Rounding_mode()) {
|
|
case ROUNDPLUS:
|
|
if (Dbl_iszero_sign(resultp1)) {
|
|
Dbl_increment(opnd3p1,opnd3p2);
|
|
}
|
|
break;
|
|
case ROUNDMINUS:
|
|
if (Dbl_isone_sign(resultp1)) {
|
|
Dbl_increment(opnd3p1,opnd3p2);
|
|
}
|
|
break;
|
|
case ROUNDNEAREST:
|
|
if (guardbit && (stickybit ||
|
|
Dbl_isone_lowmantissap2(opnd3p2))) {
|
|
Dbl_increment(opnd3p1,opnd3p2);
|
|
}
|
|
break;
|
|
}
|
|
if (is_tiny) Set_underflowflag();
|
|
}
|
|
Dbl_set_exponentmantissa(resultp1,resultp2,opnd3p1,opnd3p2);
|
|
}
|
|
else Dbl_set_exponent(resultp1,dest_exponent);
|
|
Dbl_copytoptr(resultp1,resultp2,dstptr);
|
|
|
|
/* check for inexact */
|
|
if (inexact) {
|
|
if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
|
|
else Set_inexactflag();
|
|
}
|
|
return(NOEXCEPTION);
|
|
}
|