383 lines
9.6 KiB
C
383 lines
9.6 KiB
C
/* $NetBSD: sfmpy.c,v 1.2 2003/07/15 02:29:43 lukem Exp $ */
|
|
|
|
/* $OpenBSD: sfmpy.c,v 1.4 2001/03/29 03:58:19 mickey Exp $ */
|
|
|
|
/*
|
|
* Copyright 1996 1995 by Open Software Foundation, Inc.
|
|
* All Rights Reserved
|
|
*
|
|
* Permission to use, copy, modify, and distribute this software and
|
|
* its documentation for any purpose and without fee is hereby granted,
|
|
* provided that the above copyright notice appears in all copies and
|
|
* that both the copyright notice and this permission notice appear in
|
|
* supporting documentation.
|
|
*
|
|
* OSF DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE
|
|
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
|
|
* FOR A PARTICULAR PURPOSE.
|
|
*
|
|
* IN NO EVENT SHALL OSF BE LIABLE FOR ANY SPECIAL, INDIRECT, OR
|
|
* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
|
|
* LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT,
|
|
* NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
|
|
* WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
|
|
*
|
|
*/
|
|
/*
|
|
* pmk1.1
|
|
*/
|
|
/*
|
|
* (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.
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
__KERNEL_RCSID(0, "$NetBSD: sfmpy.c,v 1.2 2003/07/15 02:29:43 lukem Exp $");
|
|
|
|
#include "../spmath/float.h"
|
|
#include "../spmath/sgl_float.h"
|
|
|
|
/*
|
|
* Single Precision Floating-point Multiply
|
|
*/
|
|
int
|
|
sgl_fmpy(srcptr1,srcptr2,dstptr,status)
|
|
|
|
sgl_floating_point *srcptr1, *srcptr2, *dstptr;
|
|
unsigned int *status;
|
|
{
|
|
register unsigned int opnd1, opnd2, opnd3, result;
|
|
register int dest_exponent, count;
|
|
register int inexact = FALSE, guardbit = FALSE, stickybit = FALSE;
|
|
int 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_iszero_exponentmantissa(opnd2)) {
|
|
/*
|
|
* invalid since operands are infinity
|
|
* and zero
|
|
*/
|
|
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)) {
|
|
if (Sgl_iszero_exponentmantissa(opnd1)) {
|
|
/* invalid since operands are zero & infinity */
|
|
if (Is_invalidtrap_enabled())
|
|
return(INVALIDEXCEPTION);
|
|
Set_invalidflag();
|
|
Sgl_makequietnan(opnd2);
|
|
*dstptr = opnd2;
|
|
return(NOEXCEPTION);
|
|
}
|
|
/*
|
|
* return infinity
|
|
*/
|
|
Sgl_setinfinity_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);
|
|
}
|
|
/*
|
|
* 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, adjust exponent */
|
|
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 {
|
|
/* check for zero */
|
|
if (Sgl_iszero_mantissa(opnd2)) {
|
|
Sgl_setzero_exponentmantissa(result);
|
|
*dstptr = result;
|
|
return(NOEXCEPTION);
|
|
}
|
|
/* is denormalized; want to normalize */
|
|
Sgl_clear_signexponent(opnd2);
|
|
Sgl_leftshiftby1(opnd2);
|
|
Sgl_normalize(opnd2,dest_exponent);
|
|
}
|
|
|
|
/* Multiply two source mantissas together */
|
|
|
|
Sgl_leftshiftby4(opnd2); /* make room for guard bits */
|
|
Sgl_setzero(opnd3);
|
|
/*
|
|
* Four bits at a time are inspected in each loop, and a
|
|
* simple shift and add multiply algorithm is used.
|
|
*/
|
|
for (count=1;count<SGL_P;count+=4) {
|
|
stickybit |= Slow4(opnd3);
|
|
Sgl_rightshiftby4(opnd3);
|
|
if (Sbit28(opnd1)) Sall(opnd3) += (Sall(opnd2) << 3);
|
|
if (Sbit29(opnd1)) Sall(opnd3) += (Sall(opnd2) << 2);
|
|
if (Sbit30(opnd1)) Sall(opnd3) += (Sall(opnd2) << 1);
|
|
if (Sbit31(opnd1)) Sall(opnd3) += Sall(opnd2);
|
|
Sgl_rightshiftby4(opnd1);
|
|
}
|
|
/* make sure result is left-justified */
|
|
if (Sgl_iszero_sign(opnd3)) {
|
|
Sgl_leftshiftby1(opnd3);
|
|
}
|
|
else {
|
|
/* result mantissa >= 2. */
|
|
dest_exponent++;
|
|
}
|
|
/* check for denormalized result */
|
|
while (Sgl_iszero_sign(opnd3)) {
|
|
Sgl_leftshiftby1(opnd3);
|
|
dest_exponent--;
|
|
}
|
|
/*
|
|
* check for guard, sticky and inexact bits
|
|
*/
|
|
stickybit |= Sgl_all(opnd3) << (SGL_BITLENGTH - SGL_EXP_LENGTH + 1);
|
|
guardbit = Sbit24(opnd3);
|
|
inexact = guardbit | stickybit;
|
|
|
|
/* re-align mantissa */
|
|
Sgl_rightshiftby8(opnd3);
|
|
|
|
/*
|
|
* 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(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 (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);
|
|
}
|
|
inexact = TRUE;
|
|
Set_overflowflag();
|
|
/* 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()) {
|
|
/*
|
|
* 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 zero or smallest 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);
|
|
}
|