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linux/arch/parisc/math-emu/sfdiv.c

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treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 150 Based on 1 normalized pattern(s): 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 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 42 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Richard Fontana <rfontana@redhat.com> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190524100845.259718220@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-24 12:04:10 +02:00
// SPDX-License-Identifier: GPL-2.0-or-later
Linux-2.6.12-rc2 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!
2005-04-16 15:20:36 -07:00
/*
* Linux/PA-RISC Project (http://www.parisc-linux.org/)
*
* Floating-point emulation code
* Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org>
*/
/*
* BEGIN_DESC
*
* File:
* @(#) pa/spmath/sfdiv.c $Revision: 1.1 $
*
* Purpose:
* Single Precision Floating-point Divide
*
* External Interfaces:
* sgl_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 "sgl_float.h"
/*
* Single Precision Floating-point Divide
*/
int
sgl_fdiv (sgl_floating_point * srcptr1, sgl_floating_point * srcptr2,
sgl_floating_point * dstptr, unsigned int *status)
{
register unsigned int opnd1, opnd2, opnd3, result;
register int dest_exponent, count;
register boolean inexact = FALSE, guardbit = FALSE, stickybit = FALSE;
boolean is_tiny;
opnd1 = *srcptr1;
opnd2 = *srcptr2;
/*
* set sign bit of result
*/
if (Sgl_sign(opnd1) ^ Sgl_sign(opnd2)) Sgl_setnegativezero(result);
else Sgl_setzero(result);
/*
* check first operand for NaN's or infinity
*/
if (Sgl_isinfinity_exponent(opnd1)) {
if (Sgl_iszero_mantissa(opnd1)) {
if (Sgl_isnotnan(opnd2)) {
if (Sgl_isinfinity(opnd2)) {
/*
* invalid since both operands
* are infinity
*/
if (Is_invalidtrap_enabled())
return(INVALIDEXCEPTION);
Set_invalidflag();
Sgl_makequietnan(result);
*dstptr = result;
return(NOEXCEPTION);
}
/*
* return infinity
*/
Sgl_setinfinity_exponentmantissa(result);
*dstptr = result;
return(NOEXCEPTION);
}
}
else {
/*
* is NaN; signaling or quiet?
*/
if (Sgl_isone_signaling(opnd1)) {
/* trap if INVALIDTRAP enabled */
if (Is_invalidtrap_enabled())
return(INVALIDEXCEPTION);
/* make NaN quiet */
Set_invalidflag();
Sgl_set_quiet(opnd1);
}
/*
* is second operand a signaling NaN?
*/
else if (Sgl_is_signalingnan(opnd2)) {
/* trap if INVALIDTRAP enabled */
if (Is_invalidtrap_enabled())
return(INVALIDEXCEPTION);
/* make NaN quiet */
Set_invalidflag();
Sgl_set_quiet(opnd2);
*dstptr = opnd2;
return(NOEXCEPTION);
}
/*
* return quiet NaN
*/
*dstptr = opnd1;
return(NOEXCEPTION);
}
}
/*
* check second operand for NaN's or infinity
*/
if (Sgl_isinfinity_exponent(opnd2)) {
if (Sgl_iszero_mantissa(opnd2)) {
/*
* return zero
*/
Sgl_setzero_exponentmantissa(result);
*dstptr = result;
return(NOEXCEPTION);
}
/*
* is NaN; signaling or quiet?
*/
if (Sgl_isone_signaling(opnd2)) {
/* trap if INVALIDTRAP enabled */
if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
/* make NaN quiet */
Set_invalidflag();
Sgl_set_quiet(opnd2);
}
/*
* return quiet NaN
*/
*dstptr = opnd2;
return(NOEXCEPTION);
}
/*
* check for division by zero
*/
if (Sgl_iszero_exponentmantissa(opnd2)) {
if (Sgl_iszero_exponentmantissa(opnd1)) {
/* invalid since both operands are zero */
if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
Set_invalidflag();
Sgl_makequietnan(result);
*dstptr = result;
return(NOEXCEPTION);
}
if (Is_divisionbyzerotrap_enabled())
return(DIVISIONBYZEROEXCEPTION);
Set_divisionbyzeroflag();
Sgl_setinfinity_exponentmantissa(result);
*dstptr = result;
return(NOEXCEPTION);
}
/*
* Generate exponent
*/
dest_exponent = Sgl_exponent(opnd1) - Sgl_exponent(opnd2) + SGL_BIAS;
/*
* Generate mantissa
*/
if (Sgl_isnotzero_exponent(opnd1)) {
/* set hidden bit */
Sgl_clear_signexponent_set_hidden(opnd1);
}
else {
/* check for zero */
if (Sgl_iszero_mantissa(opnd1)) {
Sgl_setzero_exponentmantissa(result);
*dstptr = result;
return(NOEXCEPTION);
}
/* is denormalized; want to normalize */
Sgl_clear_signexponent(opnd1);
Sgl_leftshiftby1(opnd1);
Sgl_normalize(opnd1,dest_exponent);
}
/* opnd2 needs to have hidden bit set with msb in hidden bit */
if (Sgl_isnotzero_exponent(opnd2)) {
Sgl_clear_signexponent_set_hidden(opnd2);
}
else {
/* is denormalized; want to normalize */
Sgl_clear_signexponent(opnd2);
Sgl_leftshiftby1(opnd2);
while(Sgl_iszero_hiddenhigh7mantissa(opnd2)) {
Sgl_leftshiftby8(opnd2);
dest_exponent += 8;
}
if(Sgl_iszero_hiddenhigh3mantissa(opnd2)) {
Sgl_leftshiftby4(opnd2);
dest_exponent += 4;
}
while(Sgl_iszero_hidden(opnd2)) {
Sgl_leftshiftby1(opnd2);
dest_exponent += 1;
}
}
/* Divide the source mantissas */
/*
* A non_restoring divide algorithm is used.
*/
Sgl_subtract(opnd1,opnd2,opnd1);
Sgl_setzero(opnd3);
for (count=1;count<=SGL_P && Sgl_all(opnd1);count++) {
Sgl_leftshiftby1(opnd1);
Sgl_leftshiftby1(opnd3);
if (Sgl_iszero_sign(opnd1)) {
Sgl_setone_lowmantissa(opnd3);
Sgl_subtract(opnd1,opnd2,opnd1);
}
else Sgl_addition(opnd1,opnd2,opnd1);
}
if (count <= SGL_P) {
Sgl_leftshiftby1(opnd3);
Sgl_setone_lowmantissa(opnd3);
Sgl_leftshift(opnd3,SGL_P-count);
if (Sgl_iszero_hidden(opnd3)) {
Sgl_leftshiftby1(opnd3);
dest_exponent--;
}
}
else {
if (Sgl_iszero_hidden(opnd3)) {
/* need to get one more bit of result */
Sgl_leftshiftby1(opnd1);
Sgl_leftshiftby1(opnd3);
if (Sgl_iszero_sign(opnd1)) {
Sgl_setone_lowmantissa(opnd3);
Sgl_subtract(opnd1,opnd2,opnd1);
}
else Sgl_addition(opnd1,opnd2,opnd1);
dest_exponent--;
}
if (Sgl_iszero_sign(opnd1)) guardbit = TRUE;
stickybit = Sgl_all(opnd1);
}
inexact = guardbit | stickybit;
/*
* round result
*/
if (inexact && (dest_exponent > 0 || Is_underflowtrap_enabled())) {
Sgl_clear_signexponent(opnd3);
switch (Rounding_mode()) {
case ROUNDPLUS:
if (Sgl_iszero_sign(result))
Sgl_increment_mantissa(opnd3);
break;
case ROUNDMINUS:
if (Sgl_isone_sign(result))
Sgl_increment_mantissa(opnd3);
break;
case ROUNDNEAREST:
if (guardbit) {
if (stickybit || Sgl_isone_lowmantissa(opnd3))
Sgl_increment_mantissa(opnd3);
}
}
if (Sgl_isone_hidden(opnd3)) dest_exponent++;
}
Sgl_set_mantissa(result,opnd3);
/*
* Test for overflow
*/
if (dest_exponent >= SGL_INFINITY_EXPONENT) {
/* trap if OVERFLOWTRAP enabled */
if (Is_overflowtrap_enabled()) {
/*
* 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();
/* set result to infinity or largest number */
Sgl_setoverflow(result);
inexact = TRUE;
}
/*
* Test for underflow
*/
else if (dest_exponent <= 0) {
/* trap if UNDERFLOWTRAP enabled */
if (Is_underflowtrap_enabled()) {
/*
* 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);
}
/* Determine if should set underflow flag */
is_tiny = TRUE;
if (dest_exponent == 0 && inexact) {
switch (Rounding_mode()) {
case ROUNDPLUS:
if (Sgl_iszero_sign(result)) {
Sgl_increment(opnd3);
if (Sgl_isone_hiddenoverflow(opnd3))
is_tiny = FALSE;
Sgl_decrement(opnd3);
}
break;
case ROUNDMINUS:
if (Sgl_isone_sign(result)) {
Sgl_increment(opnd3);
if (Sgl_isone_hiddenoverflow(opnd3))
is_tiny = FALSE;
Sgl_decrement(opnd3);
}
break;
case ROUNDNEAREST:
if (guardbit && (stickybit ||
Sgl_isone_lowmantissa(opnd3))) {
Sgl_increment(opnd3);
if (Sgl_isone_hiddenoverflow(opnd3))
is_tiny = FALSE;
Sgl_decrement(opnd3);
}
break;
}
}
/*
* denormalize result or set to signed zero
*/
stickybit = inexact;
Sgl_denormalize(opnd3,dest_exponent,guardbit,stickybit,inexact);
/* return rounded number */
if (inexact) {
switch (Rounding_mode()) {
case ROUNDPLUS:
if (Sgl_iszero_sign(result)) {
Sgl_increment(opnd3);
}
break;
case ROUNDMINUS:
if (Sgl_isone_sign(result)) {
Sgl_increment(opnd3);
}
break;
case ROUNDNEAREST:
if (guardbit && (stickybit ||
Sgl_isone_lowmantissa(opnd3))) {
Sgl_increment(opnd3);
}
break;
}
if (is_tiny) Set_underflowflag();
}
Sgl_set_exponentmantissa(result,opnd3);
}
else Sgl_set_exponent(result,dest_exponent);
*dstptr = result;
/* check for inexact */
if (inexact) {
if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
else Set_inexactflag();
}
return(NOEXCEPTION);
}
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