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linux/arch/parisc/math-emu/fmpyfadd.c
Thomas Gleixner 660662f857 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>
2019-05-30 11:25:19 -07:00

2643 lines
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* 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/fmpyfadd.c $Revision: 1.1 $
*
* Purpose:
* Double Floating-point Multiply Fused Add
* Double Floating-point Multiply Negate Fused Add
* Single Floating-point Multiply Fused Add
* Single Floating-point Multiply Negate Fused Add
*
* External Interfaces:
* dbl_fmpyfadd(src1ptr,src2ptr,src3ptr,status,dstptr)
* dbl_fmpynfadd(src1ptr,src2ptr,src3ptr,status,dstptr)
* sgl_fmpyfadd(src1ptr,src2ptr,src3ptr,status,dstptr)
* sgl_fmpynfadd(src1ptr,src2ptr,src3ptr,status,dstptr)
*
* 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"
/*
* Double Floating-point Multiply Fused Add
*/
int
dbl_fmpyfadd(
dbl_floating_point *src1ptr,
dbl_floating_point *src2ptr,
dbl_floating_point *src3ptr,
unsigned int *status,
dbl_floating_point *dstptr)
{
unsigned int opnd1p1, opnd1p2, opnd2p1, opnd2p2, opnd3p1, opnd3p2;
register unsigned int tmpresp1, tmpresp2, tmpresp3, tmpresp4;
unsigned int rightp1, rightp2, rightp3, rightp4;
unsigned int resultp1, resultp2 = 0, resultp3 = 0, resultp4 = 0;
register int mpy_exponent, add_exponent, count;
boolean inexact = FALSE, is_tiny = FALSE;
unsigned int signlessleft1, signlessright1, save;
register int result_exponent, diff_exponent;
int sign_save, jumpsize;
Dbl_copyfromptr(src1ptr,opnd1p1,opnd1p2);
Dbl_copyfromptr(src2ptr,opnd2p1,opnd2p2);
Dbl_copyfromptr(src3ptr,opnd3p1,opnd3p2);
/*
* set sign bit of result of multiply
*/
if (Dbl_sign(opnd1p1) ^ Dbl_sign(opnd2p1))
Dbl_setnegativezerop1(resultp1);
else Dbl_setzerop1(resultp1);
/*
* Generate multiply exponent
*/
mpy_exponent = Dbl_exponent(opnd1p1) + Dbl_exponent(opnd2p1) - DBL_BIAS;
/*
* check first operand for NaN's or infinity
*/
if (Dbl_isinfinity_exponent(opnd1p1)) {
if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) {
if (Dbl_isnotnan(opnd2p1,opnd2p2) &&
Dbl_isnotnan(opnd3p1,opnd3p2)) {
if (Dbl_iszero_exponentmantissa(opnd2p1,opnd2p2)) {
/*
* invalid since operands are infinity
* and zero
*/
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
Set_invalidflag();
Dbl_makequietnan(resultp1,resultp2);
Dbl_copytoptr(resultp1,resultp2,dstptr);
return(NOEXCEPTION);
}
/*
* Check third operand for infinity with a
* sign opposite of the multiply result
*/
if (Dbl_isinfinity(opnd3p1,opnd3p2) &&
(Dbl_sign(resultp1) ^ Dbl_sign(opnd3p1))) {
/*
* invalid since attempting a magnitude
* subtraction of infinities
*/
if (Is_invalidtrap_enabled())
return(OPC_2E_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(OPC_2E_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(OPC_2E_INVALIDEXCEPTION);
/* make NaN quiet */
Set_invalidflag();
Dbl_set_quiet(opnd2p1);
Dbl_copytoptr(opnd2p1,opnd2p2,dstptr);
return(NOEXCEPTION);
}
/*
* is third operand a signaling NaN?
*/
else if (Dbl_is_signalingnan(opnd3p1)) {
/* trap if INVALIDTRAP enabled */
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
/* make NaN quiet */
Set_invalidflag();
Dbl_set_quiet(opnd3p1);
Dbl_copytoptr(opnd3p1,opnd3p2,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)) {
if (Dbl_isnotnan(opnd3p1,opnd3p2)) {
if (Dbl_iszero_exponentmantissa(opnd1p1,opnd1p2)) {
/*
* invalid since multiply operands are
* zero & infinity
*/
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
Set_invalidflag();
Dbl_makequietnan(opnd2p1,opnd2p2);
Dbl_copytoptr(opnd2p1,opnd2p2,dstptr);
return(NOEXCEPTION);
}
/*
* Check third operand for infinity with a
* sign opposite of the multiply result
*/
if (Dbl_isinfinity(opnd3p1,opnd3p2) &&
(Dbl_sign(resultp1) ^ Dbl_sign(opnd3p1))) {
/*
* invalid since attempting a magnitude
* subtraction of infinities
*/
if (Is_invalidtrap_enabled())
return(OPC_2E_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(opnd2p1)) {
/* trap if INVALIDTRAP enabled */
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
/* make NaN quiet */
Set_invalidflag();
Dbl_set_quiet(opnd2p1);
}
/*
* is third operand a signaling NaN?
*/
else if (Dbl_is_signalingnan(opnd3p1)) {
/* trap if INVALIDTRAP enabled */
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
/* make NaN quiet */
Set_invalidflag();
Dbl_set_quiet(opnd3p1);
Dbl_copytoptr(opnd3p1,opnd3p2,dstptr);
return(NOEXCEPTION);
}
/*
* return quiet NaN
*/
Dbl_copytoptr(opnd2p1,opnd2p2,dstptr);
return(NOEXCEPTION);
}
}
/*
* check third operand for NaN's or infinity
*/
if (Dbl_isinfinity_exponent(opnd3p1)) {
if (Dbl_iszero_mantissa(opnd3p1,opnd3p2)) {
/* return infinity */
Dbl_copytoptr(opnd3p1,opnd3p2,dstptr);
return(NOEXCEPTION);
} else {
/*
* is NaN; signaling or quiet?
*/
if (Dbl_isone_signaling(opnd3p1)) {
/* trap if INVALIDTRAP enabled */
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
/* make NaN quiet */
Set_invalidflag();
Dbl_set_quiet(opnd3p1);
}
/*
* return quiet NaN
*/
Dbl_copytoptr(opnd3p1,opnd3p2,dstptr);
return(NOEXCEPTION);
}
}
/*
* Generate multiply 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)) {
/*
* Perform the add opnd3 with zero here.
*/
if (Dbl_iszero_exponentmantissa(opnd3p1,opnd3p2)) {
if (Is_rounding_mode(ROUNDMINUS)) {
Dbl_or_signs(opnd3p1,resultp1);
} else {
Dbl_and_signs(opnd3p1,resultp1);
}
}
/*
* Now let's check for trapped underflow case.
*/
else if (Dbl_iszero_exponent(opnd3p1) &&
Is_underflowtrap_enabled()) {
/* need to normalize results mantissa */
sign_save = Dbl_signextendedsign(opnd3p1);
result_exponent = 0;
Dbl_leftshiftby1(opnd3p1,opnd3p2);
Dbl_normalize(opnd3p1,opnd3p2,result_exponent);
Dbl_set_sign(opnd3p1,/*using*/sign_save);
Dbl_setwrapped_exponent(opnd3p1,result_exponent,
unfl);
Dbl_copytoptr(opnd3p1,opnd3p2,dstptr);
/* inexact = FALSE */
return(OPC_2E_UNDERFLOWEXCEPTION);
}
Dbl_copytoptr(opnd3p1,opnd3p2,dstptr);
return(NOEXCEPTION);
}
/* is denormalized, adjust exponent */
Dbl_clear_signexponent(opnd1p1);
Dbl_leftshiftby1(opnd1p1,opnd1p2);
Dbl_normalize(opnd1p1,opnd1p2,mpy_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 {
/* check for zero */
if (Dbl_iszero_mantissa(opnd2p1,opnd2p2)) {
/*
* Perform the add opnd3 with zero here.
*/
if (Dbl_iszero_exponentmantissa(opnd3p1,opnd3p2)) {
if (Is_rounding_mode(ROUNDMINUS)) {
Dbl_or_signs(opnd3p1,resultp1);
} else {
Dbl_and_signs(opnd3p1,resultp1);
}
}
/*
* Now let's check for trapped underflow case.
*/
else if (Dbl_iszero_exponent(opnd3p1) &&
Is_underflowtrap_enabled()) {
/* need to normalize results mantissa */
sign_save = Dbl_signextendedsign(opnd3p1);
result_exponent = 0;
Dbl_leftshiftby1(opnd3p1,opnd3p2);
Dbl_normalize(opnd3p1,opnd3p2,result_exponent);
Dbl_set_sign(opnd3p1,/*using*/sign_save);
Dbl_setwrapped_exponent(opnd3p1,result_exponent,
unfl);
Dbl_copytoptr(opnd3p1,opnd3p2,dstptr);
/* inexact = FALSE */
return(OPC_2E_UNDERFLOWEXCEPTION);
}
Dbl_copytoptr(opnd3p1,opnd3p2,dstptr);
return(NOEXCEPTION);
}
/* is denormalized; want to normalize */
Dbl_clear_signexponent(opnd2p1);
Dbl_leftshiftby1(opnd2p1,opnd2p2);
Dbl_normalize(opnd2p1,opnd2p2,mpy_exponent);
}
/* Multiply the first two source mantissas together */
/*
* The intermediate result will be kept in tmpres,
* which needs enough room for 106 bits of mantissa,
* so lets call it a Double extended.
*/
Dblext_setzero(tmpresp1,tmpresp2,tmpresp3,tmpresp4);
/*
* Four bits at a time are inspected in each loop, and a
* simple shift and add multiply algorithm is used.
*/
for (count = DBL_P-1; count >= 0; count -= 4) {
Dblext_rightshiftby4(tmpresp1,tmpresp2,tmpresp3,tmpresp4);
if (Dbit28p2(opnd1p2)) {
/* Fourword_add should be an ADD followed by 3 ADDC's */
Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4,
opnd2p1<<3 | opnd2p2>>29, opnd2p2<<3, 0, 0);
}
if (Dbit29p2(opnd1p2)) {
Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4,
opnd2p1<<2 | opnd2p2>>30, opnd2p2<<2, 0, 0);
}
if (Dbit30p2(opnd1p2)) {
Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4,
opnd2p1<<1 | opnd2p2>>31, opnd2p2<<1, 0, 0);
}
if (Dbit31p2(opnd1p2)) {
Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4,
opnd2p1, opnd2p2, 0, 0);
}
Dbl_rightshiftby4(opnd1p1,opnd1p2);
}
if (Is_dexthiddenoverflow(tmpresp1)) {
/* result mantissa >= 2 (mantissa overflow) */
mpy_exponent++;
Dblext_rightshiftby1(tmpresp1,tmpresp2,tmpresp3,tmpresp4);
}
/*
* Restore the sign of the mpy result which was saved in resultp1.
* The exponent will continue to be kept in mpy_exponent.
*/
Dblext_set_sign(tmpresp1,Dbl_sign(resultp1));
/*
* No rounding is required, since the result of the multiply
* is exact in the extended format.
*/
/*
* Now we are ready to perform the add portion of the operation.
*
* The exponents need to be kept as integers for now, since the
* multiply result might not fit into the exponent field. We
* can't overflow or underflow because of this yet, since the
* add could bring the final result back into range.
*/
add_exponent = Dbl_exponent(opnd3p1);
/*
* Check for denormalized or zero add operand.
*/
if (add_exponent == 0) {
/* check for zero */
if (Dbl_iszero_mantissa(opnd3p1,opnd3p2)) {
/* right is zero */
/* Left can't be zero and must be result.
*
* The final result is now in tmpres and mpy_exponent,
* and needs to be rounded and squeezed back into
* double precision format from double extended.
*/
result_exponent = mpy_exponent;
Dblext_copy(tmpresp1,tmpresp2,tmpresp3,tmpresp4,
resultp1,resultp2,resultp3,resultp4);
sign_save = Dbl_signextendedsign(resultp1);/*save sign*/
goto round;
}
/*
* Neither are zeroes.
* Adjust exponent and normalize add operand.
*/
sign_save = Dbl_signextendedsign(opnd3p1); /* save sign */
Dbl_clear_signexponent(opnd3p1);
Dbl_leftshiftby1(opnd3p1,opnd3p2);
Dbl_normalize(opnd3p1,opnd3p2,add_exponent);
Dbl_set_sign(opnd3p1,sign_save); /* restore sign */
} else {
Dbl_clear_exponent_set_hidden(opnd3p1);
}
/*
* Copy opnd3 to the double extended variable called right.
*/
Dbl_copyto_dblext(opnd3p1,opnd3p2,rightp1,rightp2,rightp3,rightp4);
/*
* A zero "save" helps discover equal operands (for later),
* and is used in swapping operands (if needed).
*/
Dblext_xortointp1(tmpresp1,rightp1,/*to*/save);
/*
* Compare magnitude of operands.
*/
Dblext_copytoint_exponentmantissap1(tmpresp1,signlessleft1);
Dblext_copytoint_exponentmantissap1(rightp1,signlessright1);
if (mpy_exponent < add_exponent || mpy_exponent == add_exponent &&
Dblext_ismagnitudeless(tmpresp2,rightp2,signlessleft1,signlessright1)){
/*
* Set the left operand to the larger one by XOR swap.
* First finish the first word "save".
*/
Dblext_xorfromintp1(save,rightp1,/*to*/rightp1);
Dblext_xorfromintp1(save,tmpresp1,/*to*/tmpresp1);
Dblext_swap_lower(tmpresp2,tmpresp3,tmpresp4,
rightp2,rightp3,rightp4);
/* also setup exponents used in rest of routine */
diff_exponent = add_exponent - mpy_exponent;
result_exponent = add_exponent;
} else {
/* also setup exponents used in rest of routine */
diff_exponent = mpy_exponent - add_exponent;
result_exponent = mpy_exponent;
}
/* Invariant: left is not smaller than right. */
/*
* Special case alignment of operands that would force alignment
* beyond the extent of the extension. A further optimization
* could special case this but only reduces the path length for
* this infrequent case.
*/
if (diff_exponent > DBLEXT_THRESHOLD) {
diff_exponent = DBLEXT_THRESHOLD;
}
/* Align right operand by shifting it to the right */
Dblext_clear_sign(rightp1);
Dblext_right_align(rightp1,rightp2,rightp3,rightp4,
/*shifted by*/diff_exponent);
/* Treat sum and difference of the operands separately. */
if ((int)save < 0) {
/*
* Difference of the two operands. Overflow can occur if the
* multiply overflowed. A borrow can occur out of the hidden
* bit and force a post normalization phase.
*/
Dblext_subtract(tmpresp1,tmpresp2,tmpresp3,tmpresp4,
rightp1,rightp2,rightp3,rightp4,
resultp1,resultp2,resultp3,resultp4);
sign_save = Dbl_signextendedsign(resultp1);
if (Dbl_iszero_hidden(resultp1)) {
/* Handle normalization */
/* A straightforward algorithm would now shift the
* result and extension left until the hidden bit
* becomes one. Not all of the extension bits need
* participate in the shift. Only the two most
* significant bits (round and guard) are needed.
* If only a single shift is needed then the guard
* bit becomes a significant low order bit and the
* extension must participate in the rounding.
* If more than a single shift is needed, then all
* bits to the right of the guard bit are zeros,
* and the guard bit may or may not be zero. */
Dblext_leftshiftby1(resultp1,resultp2,resultp3,
resultp4);
/* Need to check for a zero result. The sign and
* exponent fields have already been zeroed. The more
* efficient test of the full object can be used.
*/
if(Dblext_iszero(resultp1,resultp2,resultp3,resultp4)){
/* Must have been "x-x" or "x+(-x)". */
if (Is_rounding_mode(ROUNDMINUS))
Dbl_setone_sign(resultp1);
Dbl_copytoptr(resultp1,resultp2,dstptr);
return(NOEXCEPTION);
}
result_exponent--;
/* Look to see if normalization is finished. */
if (Dbl_isone_hidden(resultp1)) {
/* No further normalization is needed */
goto round;
}
/* Discover first one bit to determine shift amount.
* Use a modified binary search. We have already
* shifted the result one position right and still
* not found a one so the remainder of the extension
* must be zero and simplifies rounding. */
/* Scan bytes */
while (Dbl_iszero_hiddenhigh7mantissa(resultp1)) {
Dblext_leftshiftby8(resultp1,resultp2,resultp3,resultp4);
result_exponent -= 8;
}
/* Now narrow it down to the nibble */
if (Dbl_iszero_hiddenhigh3mantissa(resultp1)) {
/* The lower nibble contains the
* normalizing one */
Dblext_leftshiftby4(resultp1,resultp2,resultp3,resultp4);
result_exponent -= 4;
}
/* Select case where first bit is set (already
* normalized) otherwise select the proper shift. */
jumpsize = Dbl_hiddenhigh3mantissa(resultp1);
if (jumpsize <= 7) switch(jumpsize) {
case 1:
Dblext_leftshiftby3(resultp1,resultp2,resultp3,
resultp4);
result_exponent -= 3;
break;
case 2:
case 3:
Dblext_leftshiftby2(resultp1,resultp2,resultp3,
resultp4);
result_exponent -= 2;
break;
case 4:
case 5:
case 6:
case 7:
Dblext_leftshiftby1(resultp1,resultp2,resultp3,
resultp4);
result_exponent -= 1;
break;
}
} /* end if (hidden...)... */
/* Fall through and round */
} /* end if (save < 0)... */
else {
/* Add magnitudes */
Dblext_addition(tmpresp1,tmpresp2,tmpresp3,tmpresp4,
rightp1,rightp2,rightp3,rightp4,
/*to*/resultp1,resultp2,resultp3,resultp4);
sign_save = Dbl_signextendedsign(resultp1);
if (Dbl_isone_hiddenoverflow(resultp1)) {
/* Prenormalization required. */
Dblext_arithrightshiftby1(resultp1,resultp2,resultp3,
resultp4);
result_exponent++;
} /* end if hiddenoverflow... */
} /* end else ...add magnitudes... */
/* Round the result. If the extension and lower two words are
* all zeros, then the result is exact. Otherwise round in the
* correct direction. Underflow is possible. If a postnormalization
* is necessary, then the mantissa is all zeros so no shift is needed.
*/
round:
if (result_exponent <= 0 && !Is_underflowtrap_enabled()) {
Dblext_denormalize(resultp1,resultp2,resultp3,resultp4,
result_exponent,is_tiny);
}
Dbl_set_sign(resultp1,/*using*/sign_save);
if (Dblext_isnotzero_mantissap3(resultp3) ||
Dblext_isnotzero_mantissap4(resultp4)) {
inexact = TRUE;
switch(Rounding_mode()) {
case ROUNDNEAREST: /* The default. */
if (Dblext_isone_highp3(resultp3)) {
/* at least 1/2 ulp */
if (Dblext_isnotzero_low31p3(resultp3) ||
Dblext_isnotzero_mantissap4(resultp4) ||
Dblext_isone_lowp2(resultp2)) {
/* either exactly half way and odd or
* more than 1/2ulp */
Dbl_increment(resultp1,resultp2);
}
}
break;
case ROUNDPLUS:
if (Dbl_iszero_sign(resultp1)) {
/* Round up positive results */
Dbl_increment(resultp1,resultp2);
}
break;
case ROUNDMINUS:
if (Dbl_isone_sign(resultp1)) {
/* Round down negative results */
Dbl_increment(resultp1,resultp2);
}
case ROUNDZERO:;
/* truncate is simple */
} /* end switch... */
if (Dbl_isone_hiddenoverflow(resultp1)) result_exponent++;
}
if (result_exponent >= DBL_INFINITY_EXPONENT) {
/* trap if OVERFLOWTRAP enabled */
if (Is_overflowtrap_enabled()) {
/*
* Adjust bias of result
*/
Dbl_setwrapped_exponent(resultp1,result_exponent,ovfl);
Dbl_copytoptr(resultp1,resultp2,dstptr);
if (inexact)
if (Is_inexacttrap_enabled())
return (OPC_2E_OVERFLOWEXCEPTION |
OPC_2E_INEXACTEXCEPTION);
else Set_inexactflag();
return (OPC_2E_OVERFLOWEXCEPTION);
}
inexact = TRUE;
Set_overflowflag();
/* set result to infinity or largest number */
Dbl_setoverflow(resultp1,resultp2);
} else if (result_exponent <= 0) { /* underflow case */
if (Is_underflowtrap_enabled()) {
/*
* Adjust bias of result
*/
Dbl_setwrapped_exponent(resultp1,result_exponent,unfl);
Dbl_copytoptr(resultp1,resultp2,dstptr);
if (inexact)
if (Is_inexacttrap_enabled())
return (OPC_2E_UNDERFLOWEXCEPTION |
OPC_2E_INEXACTEXCEPTION);
else Set_inexactflag();
return(OPC_2E_UNDERFLOWEXCEPTION);
}
else if (inexact && is_tiny) Set_underflowflag();
}
else Dbl_set_exponent(resultp1,result_exponent);
Dbl_copytoptr(resultp1,resultp2,dstptr);
if (inexact)
if (Is_inexacttrap_enabled()) return(OPC_2E_INEXACTEXCEPTION);
else Set_inexactflag();
return(NOEXCEPTION);
}
/*
* Double Floating-point Multiply Negate Fused Add
*/
dbl_fmpynfadd(src1ptr,src2ptr,src3ptr,status,dstptr)
dbl_floating_point *src1ptr, *src2ptr, *src3ptr, *dstptr;
unsigned int *status;
{
unsigned int opnd1p1, opnd1p2, opnd2p1, opnd2p2, opnd3p1, opnd3p2;
register unsigned int tmpresp1, tmpresp2, tmpresp3, tmpresp4;
unsigned int rightp1, rightp2, rightp3, rightp4;
unsigned int resultp1, resultp2 = 0, resultp3 = 0, resultp4 = 0;
register int mpy_exponent, add_exponent, count;
boolean inexact = FALSE, is_tiny = FALSE;
unsigned int signlessleft1, signlessright1, save;
register int result_exponent, diff_exponent;
int sign_save, jumpsize;
Dbl_copyfromptr(src1ptr,opnd1p1,opnd1p2);
Dbl_copyfromptr(src2ptr,opnd2p1,opnd2p2);
Dbl_copyfromptr(src3ptr,opnd3p1,opnd3p2);
/*
* set sign bit of result of multiply
*/
if (Dbl_sign(opnd1p1) ^ Dbl_sign(opnd2p1))
Dbl_setzerop1(resultp1);
else
Dbl_setnegativezerop1(resultp1);
/*
* Generate multiply exponent
*/
mpy_exponent = Dbl_exponent(opnd1p1) + Dbl_exponent(opnd2p1) - DBL_BIAS;
/*
* check first operand for NaN's or infinity
*/
if (Dbl_isinfinity_exponent(opnd1p1)) {
if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) {
if (Dbl_isnotnan(opnd2p1,opnd2p2) &&
Dbl_isnotnan(opnd3p1,opnd3p2)) {
if (Dbl_iszero_exponentmantissa(opnd2p1,opnd2p2)) {
/*
* invalid since operands are infinity
* and zero
*/
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
Set_invalidflag();
Dbl_makequietnan(resultp1,resultp2);
Dbl_copytoptr(resultp1,resultp2,dstptr);
return(NOEXCEPTION);
}
/*
* Check third operand for infinity with a
* sign opposite of the multiply result
*/
if (Dbl_isinfinity(opnd3p1,opnd3p2) &&
(Dbl_sign(resultp1) ^ Dbl_sign(opnd3p1))) {
/*
* invalid since attempting a magnitude
* subtraction of infinities
*/
if (Is_invalidtrap_enabled())
return(OPC_2E_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(OPC_2E_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(OPC_2E_INVALIDEXCEPTION);
/* make NaN quiet */
Set_invalidflag();
Dbl_set_quiet(opnd2p1);
Dbl_copytoptr(opnd2p1,opnd2p2,dstptr);
return(NOEXCEPTION);
}
/*
* is third operand a signaling NaN?
*/
else if (Dbl_is_signalingnan(opnd3p1)) {
/* trap if INVALIDTRAP enabled */
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
/* make NaN quiet */
Set_invalidflag();
Dbl_set_quiet(opnd3p1);
Dbl_copytoptr(opnd3p1,opnd3p2,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)) {
if (Dbl_isnotnan(opnd3p1,opnd3p2)) {
if (Dbl_iszero_exponentmantissa(opnd1p1,opnd1p2)) {
/*
* invalid since multiply operands are
* zero & infinity
*/
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
Set_invalidflag();
Dbl_makequietnan(opnd2p1,opnd2p2);
Dbl_copytoptr(opnd2p1,opnd2p2,dstptr);
return(NOEXCEPTION);
}
/*
* Check third operand for infinity with a
* sign opposite of the multiply result
*/
if (Dbl_isinfinity(opnd3p1,opnd3p2) &&
(Dbl_sign(resultp1) ^ Dbl_sign(opnd3p1))) {
/*
* invalid since attempting a magnitude
* subtraction of infinities
*/
if (Is_invalidtrap_enabled())
return(OPC_2E_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(opnd2p1)) {
/* trap if INVALIDTRAP enabled */
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
/* make NaN quiet */
Set_invalidflag();
Dbl_set_quiet(opnd2p1);
}
/*
* is third operand a signaling NaN?
*/
else if (Dbl_is_signalingnan(opnd3p1)) {
/* trap if INVALIDTRAP enabled */
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
/* make NaN quiet */
Set_invalidflag();
Dbl_set_quiet(opnd3p1);
Dbl_copytoptr(opnd3p1,opnd3p2,dstptr);
return(NOEXCEPTION);
}
/*
* return quiet NaN
*/
Dbl_copytoptr(opnd2p1,opnd2p2,dstptr);
return(NOEXCEPTION);
}
}
/*
* check third operand for NaN's or infinity
*/
if (Dbl_isinfinity_exponent(opnd3p1)) {
if (Dbl_iszero_mantissa(opnd3p1,opnd3p2)) {
/* return infinity */
Dbl_copytoptr(opnd3p1,opnd3p2,dstptr);
return(NOEXCEPTION);
} else {
/*
* is NaN; signaling or quiet?
*/
if (Dbl_isone_signaling(opnd3p1)) {
/* trap if INVALIDTRAP enabled */
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
/* make NaN quiet */
Set_invalidflag();
Dbl_set_quiet(opnd3p1);
}
/*
* return quiet NaN
*/
Dbl_copytoptr(opnd3p1,opnd3p2,dstptr);
return(NOEXCEPTION);
}
}
/*
* Generate multiply 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)) {
/*
* Perform the add opnd3 with zero here.
*/
if (Dbl_iszero_exponentmantissa(opnd3p1,opnd3p2)) {
if (Is_rounding_mode(ROUNDMINUS)) {
Dbl_or_signs(opnd3p1,resultp1);
} else {
Dbl_and_signs(opnd3p1,resultp1);
}
}
/*
* Now let's check for trapped underflow case.
*/
else if (Dbl_iszero_exponent(opnd3p1) &&
Is_underflowtrap_enabled()) {
/* need to normalize results mantissa */
sign_save = Dbl_signextendedsign(opnd3p1);
result_exponent = 0;
Dbl_leftshiftby1(opnd3p1,opnd3p2);
Dbl_normalize(opnd3p1,opnd3p2,result_exponent);
Dbl_set_sign(opnd3p1,/*using*/sign_save);
Dbl_setwrapped_exponent(opnd3p1,result_exponent,
unfl);
Dbl_copytoptr(opnd3p1,opnd3p2,dstptr);
/* inexact = FALSE */
return(OPC_2E_UNDERFLOWEXCEPTION);
}
Dbl_copytoptr(opnd3p1,opnd3p2,dstptr);
return(NOEXCEPTION);
}
/* is denormalized, adjust exponent */
Dbl_clear_signexponent(opnd1p1);
Dbl_leftshiftby1(opnd1p1,opnd1p2);
Dbl_normalize(opnd1p1,opnd1p2,mpy_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 {
/* check for zero */
if (Dbl_iszero_mantissa(opnd2p1,opnd2p2)) {
/*
* Perform the add opnd3 with zero here.
*/
if (Dbl_iszero_exponentmantissa(opnd3p1,opnd3p2)) {
if (Is_rounding_mode(ROUNDMINUS)) {
Dbl_or_signs(opnd3p1,resultp1);
} else {
Dbl_and_signs(opnd3p1,resultp1);
}
}
/*
* Now let's check for trapped underflow case.
*/
else if (Dbl_iszero_exponent(opnd3p1) &&
Is_underflowtrap_enabled()) {
/* need to normalize results mantissa */
sign_save = Dbl_signextendedsign(opnd3p1);
result_exponent = 0;
Dbl_leftshiftby1(opnd3p1,opnd3p2);
Dbl_normalize(opnd3p1,opnd3p2,result_exponent);
Dbl_set_sign(opnd3p1,/*using*/sign_save);
Dbl_setwrapped_exponent(opnd3p1,result_exponent,
unfl);
Dbl_copytoptr(opnd3p1,opnd3p2,dstptr);
/* inexact = FALSE */
return(OPC_2E_UNDERFLOWEXCEPTION);
}
Dbl_copytoptr(opnd3p1,opnd3p2,dstptr);
return(NOEXCEPTION);
}
/* is denormalized; want to normalize */
Dbl_clear_signexponent(opnd2p1);
Dbl_leftshiftby1(opnd2p1,opnd2p2);
Dbl_normalize(opnd2p1,opnd2p2,mpy_exponent);
}
/* Multiply the first two source mantissas together */
/*
* The intermediate result will be kept in tmpres,
* which needs enough room for 106 bits of mantissa,
* so lets call it a Double extended.
*/
Dblext_setzero(tmpresp1,tmpresp2,tmpresp3,tmpresp4);
/*
* Four bits at a time are inspected in each loop, and a
* simple shift and add multiply algorithm is used.
*/
for (count = DBL_P-1; count >= 0; count -= 4) {
Dblext_rightshiftby4(tmpresp1,tmpresp2,tmpresp3,tmpresp4);
if (Dbit28p2(opnd1p2)) {
/* Fourword_add should be an ADD followed by 3 ADDC's */
Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4,
opnd2p1<<3 | opnd2p2>>29, opnd2p2<<3, 0, 0);
}
if (Dbit29p2(opnd1p2)) {
Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4,
opnd2p1<<2 | opnd2p2>>30, opnd2p2<<2, 0, 0);
}
if (Dbit30p2(opnd1p2)) {
Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4,
opnd2p1<<1 | opnd2p2>>31, opnd2p2<<1, 0, 0);
}
if (Dbit31p2(opnd1p2)) {
Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4,
opnd2p1, opnd2p2, 0, 0);
}
Dbl_rightshiftby4(opnd1p1,opnd1p2);
}
if (Is_dexthiddenoverflow(tmpresp1)) {
/* result mantissa >= 2 (mantissa overflow) */
mpy_exponent++;
Dblext_rightshiftby1(tmpresp1,tmpresp2,tmpresp3,tmpresp4);
}
/*
* Restore the sign of the mpy result which was saved in resultp1.
* The exponent will continue to be kept in mpy_exponent.
*/
Dblext_set_sign(tmpresp1,Dbl_sign(resultp1));
/*
* No rounding is required, since the result of the multiply
* is exact in the extended format.
*/
/*
* Now we are ready to perform the add portion of the operation.
*
* The exponents need to be kept as integers for now, since the
* multiply result might not fit into the exponent field. We
* can't overflow or underflow because of this yet, since the
* add could bring the final result back into range.
*/
add_exponent = Dbl_exponent(opnd3p1);
/*
* Check for denormalized or zero add operand.
*/
if (add_exponent == 0) {
/* check for zero */
if (Dbl_iszero_mantissa(opnd3p1,opnd3p2)) {
/* right is zero */
/* Left can't be zero and must be result.
*
* The final result is now in tmpres and mpy_exponent,
* and needs to be rounded and squeezed back into
* double precision format from double extended.
*/
result_exponent = mpy_exponent;
Dblext_copy(tmpresp1,tmpresp2,tmpresp3,tmpresp4,
resultp1,resultp2,resultp3,resultp4);
sign_save = Dbl_signextendedsign(resultp1);/*save sign*/
goto round;
}
/*
* Neither are zeroes.
* Adjust exponent and normalize add operand.
*/
sign_save = Dbl_signextendedsign(opnd3p1); /* save sign */
Dbl_clear_signexponent(opnd3p1);
Dbl_leftshiftby1(opnd3p1,opnd3p2);
Dbl_normalize(opnd3p1,opnd3p2,add_exponent);
Dbl_set_sign(opnd3p1,sign_save); /* restore sign */
} else {
Dbl_clear_exponent_set_hidden(opnd3p1);
}
/*
* Copy opnd3 to the double extended variable called right.
*/
Dbl_copyto_dblext(opnd3p1,opnd3p2,rightp1,rightp2,rightp3,rightp4);
/*
* A zero "save" helps discover equal operands (for later),
* and is used in swapping operands (if needed).
*/
Dblext_xortointp1(tmpresp1,rightp1,/*to*/save);
/*
* Compare magnitude of operands.
*/
Dblext_copytoint_exponentmantissap1(tmpresp1,signlessleft1);
Dblext_copytoint_exponentmantissap1(rightp1,signlessright1);
if (mpy_exponent < add_exponent || mpy_exponent == add_exponent &&
Dblext_ismagnitudeless(tmpresp2,rightp2,signlessleft1,signlessright1)){
/*
* Set the left operand to the larger one by XOR swap.
* First finish the first word "save".
*/
Dblext_xorfromintp1(save,rightp1,/*to*/rightp1);
Dblext_xorfromintp1(save,tmpresp1,/*to*/tmpresp1);
Dblext_swap_lower(tmpresp2,tmpresp3,tmpresp4,
rightp2,rightp3,rightp4);
/* also setup exponents used in rest of routine */
diff_exponent = add_exponent - mpy_exponent;
result_exponent = add_exponent;
} else {
/* also setup exponents used in rest of routine */
diff_exponent = mpy_exponent - add_exponent;
result_exponent = mpy_exponent;
}
/* Invariant: left is not smaller than right. */
/*
* Special case alignment of operands that would force alignment
* beyond the extent of the extension. A further optimization
* could special case this but only reduces the path length for
* this infrequent case.
*/
if (diff_exponent > DBLEXT_THRESHOLD) {
diff_exponent = DBLEXT_THRESHOLD;
}
/* Align right operand by shifting it to the right */
Dblext_clear_sign(rightp1);
Dblext_right_align(rightp1,rightp2,rightp3,rightp4,
/*shifted by*/diff_exponent);
/* Treat sum and difference of the operands separately. */
if ((int)save < 0) {
/*
* Difference of the two operands. Overflow can occur if the
* multiply overflowed. A borrow can occur out of the hidden
* bit and force a post normalization phase.
*/
Dblext_subtract(tmpresp1,tmpresp2,tmpresp3,tmpresp4,
rightp1,rightp2,rightp3,rightp4,
resultp1,resultp2,resultp3,resultp4);
sign_save = Dbl_signextendedsign(resultp1);
if (Dbl_iszero_hidden(resultp1)) {
/* Handle normalization */
/* A straightforward algorithm would now shift the
* result and extension left until the hidden bit
* becomes one. Not all of the extension bits need
* participate in the shift. Only the two most
* significant bits (round and guard) are needed.
* If only a single shift is needed then the guard
* bit becomes a significant low order bit and the
* extension must participate in the rounding.
* If more than a single shift is needed, then all
* bits to the right of the guard bit are zeros,
* and the guard bit may or may not be zero. */
Dblext_leftshiftby1(resultp1,resultp2,resultp3,
resultp4);
/* Need to check for a zero result. The sign and
* exponent fields have already been zeroed. The more
* efficient test of the full object can be used.
*/
if (Dblext_iszero(resultp1,resultp2,resultp3,resultp4)) {
/* Must have been "x-x" or "x+(-x)". */
if (Is_rounding_mode(ROUNDMINUS))
Dbl_setone_sign(resultp1);
Dbl_copytoptr(resultp1,resultp2,dstptr);
return(NOEXCEPTION);
}
result_exponent--;
/* Look to see if normalization is finished. */
if (Dbl_isone_hidden(resultp1)) {
/* No further normalization is needed */
goto round;
}
/* Discover first one bit to determine shift amount.
* Use a modified binary search. We have already
* shifted the result one position right and still
* not found a one so the remainder of the extension
* must be zero and simplifies rounding. */
/* Scan bytes */
while (Dbl_iszero_hiddenhigh7mantissa(resultp1)) {
Dblext_leftshiftby8(resultp1,resultp2,resultp3,resultp4);
result_exponent -= 8;
}
/* Now narrow it down to the nibble */
if (Dbl_iszero_hiddenhigh3mantissa(resultp1)) {
/* The lower nibble contains the
* normalizing one */
Dblext_leftshiftby4(resultp1,resultp2,resultp3,resultp4);
result_exponent -= 4;
}
/* Select case where first bit is set (already
* normalized) otherwise select the proper shift. */
jumpsize = Dbl_hiddenhigh3mantissa(resultp1);
if (jumpsize <= 7) switch(jumpsize) {
case 1:
Dblext_leftshiftby3(resultp1,resultp2,resultp3,
resultp4);
result_exponent -= 3;
break;
case 2:
case 3:
Dblext_leftshiftby2(resultp1,resultp2,resultp3,
resultp4);
result_exponent -= 2;
break;
case 4:
case 5:
case 6:
case 7:
Dblext_leftshiftby1(resultp1,resultp2,resultp3,
resultp4);
result_exponent -= 1;
break;
}
} /* end if (hidden...)... */
/* Fall through and round */
} /* end if (save < 0)... */
else {
/* Add magnitudes */
Dblext_addition(tmpresp1,tmpresp2,tmpresp3,tmpresp4,
rightp1,rightp2,rightp3,rightp4,
/*to*/resultp1,resultp2,resultp3,resultp4);
sign_save = Dbl_signextendedsign(resultp1);
if (Dbl_isone_hiddenoverflow(resultp1)) {
/* Prenormalization required. */
Dblext_arithrightshiftby1(resultp1,resultp2,resultp3,
resultp4);
result_exponent++;
} /* end if hiddenoverflow... */
} /* end else ...add magnitudes... */
/* Round the result. If the extension and lower two words are
* all zeros, then the result is exact. Otherwise round in the
* correct direction. Underflow is possible. If a postnormalization
* is necessary, then the mantissa is all zeros so no shift is needed.
*/
round:
if (result_exponent <= 0 && !Is_underflowtrap_enabled()) {
Dblext_denormalize(resultp1,resultp2,resultp3,resultp4,
result_exponent,is_tiny);
}
Dbl_set_sign(resultp1,/*using*/sign_save);
if (Dblext_isnotzero_mantissap3(resultp3) ||
Dblext_isnotzero_mantissap4(resultp4)) {
inexact = TRUE;
switch(Rounding_mode()) {
case ROUNDNEAREST: /* The default. */
if (Dblext_isone_highp3(resultp3)) {
/* at least 1/2 ulp */
if (Dblext_isnotzero_low31p3(resultp3) ||
Dblext_isnotzero_mantissap4(resultp4) ||
Dblext_isone_lowp2(resultp2)) {
/* either exactly half way and odd or
* more than 1/2ulp */
Dbl_increment(resultp1,resultp2);
}
}
break;
case ROUNDPLUS:
if (Dbl_iszero_sign(resultp1)) {
/* Round up positive results */
Dbl_increment(resultp1,resultp2);
}
break;
case ROUNDMINUS:
if (Dbl_isone_sign(resultp1)) {
/* Round down negative results */
Dbl_increment(resultp1,resultp2);
}
case ROUNDZERO:;
/* truncate is simple */
} /* end switch... */
if (Dbl_isone_hiddenoverflow(resultp1)) result_exponent++;
}
if (result_exponent >= DBL_INFINITY_EXPONENT) {
/* Overflow */
if (Is_overflowtrap_enabled()) {
/*
* Adjust bias of result
*/
Dbl_setwrapped_exponent(resultp1,result_exponent,ovfl);
Dbl_copytoptr(resultp1,resultp2,dstptr);
if (inexact)
if (Is_inexacttrap_enabled())
return (OPC_2E_OVERFLOWEXCEPTION |
OPC_2E_INEXACTEXCEPTION);
else Set_inexactflag();
return (OPC_2E_OVERFLOWEXCEPTION);
}
inexact = TRUE;
Set_overflowflag();
Dbl_setoverflow(resultp1,resultp2);
} else if (result_exponent <= 0) { /* underflow case */
if (Is_underflowtrap_enabled()) {
/*
* Adjust bias of result
*/
Dbl_setwrapped_exponent(resultp1,result_exponent,unfl);
Dbl_copytoptr(resultp1,resultp2,dstptr);
if (inexact)
if (Is_inexacttrap_enabled())
return (OPC_2E_UNDERFLOWEXCEPTION |
OPC_2E_INEXACTEXCEPTION);
else Set_inexactflag();
return(OPC_2E_UNDERFLOWEXCEPTION);
}
else if (inexact && is_tiny) Set_underflowflag();
}
else Dbl_set_exponent(resultp1,result_exponent);
Dbl_copytoptr(resultp1,resultp2,dstptr);
if (inexact)
if (Is_inexacttrap_enabled()) return(OPC_2E_INEXACTEXCEPTION);
else Set_inexactflag();
return(NOEXCEPTION);
}
/*
* Single Floating-point Multiply Fused Add
*/
sgl_fmpyfadd(src1ptr,src2ptr,src3ptr,status,dstptr)
sgl_floating_point *src1ptr, *src2ptr, *src3ptr, *dstptr;
unsigned int *status;
{
unsigned int opnd1, opnd2, opnd3;
register unsigned int tmpresp1, tmpresp2;
unsigned int rightp1, rightp2;
unsigned int resultp1, resultp2 = 0;
register int mpy_exponent, add_exponent, count;
boolean inexact = FALSE, is_tiny = FALSE;
unsigned int signlessleft1, signlessright1, save;
register int result_exponent, diff_exponent;
int sign_save, jumpsize;
Sgl_copyfromptr(src1ptr,opnd1);
Sgl_copyfromptr(src2ptr,opnd2);
Sgl_copyfromptr(src3ptr,opnd3);
/*
* set sign bit of result of multiply
*/
if (Sgl_sign(opnd1) ^ Sgl_sign(opnd2))
Sgl_setnegativezero(resultp1);
else Sgl_setzero(resultp1);
/*
* Generate multiply exponent
*/
mpy_exponent = Sgl_exponent(opnd1) + Sgl_exponent(opnd2) - SGL_BIAS;
/*
* check first operand for NaN's or infinity
*/
if (Sgl_isinfinity_exponent(opnd1)) {
if (Sgl_iszero_mantissa(opnd1)) {
if (Sgl_isnotnan(opnd2) && Sgl_isnotnan(opnd3)) {
if (Sgl_iszero_exponentmantissa(opnd2)) {
/*
* invalid since operands are infinity
* and zero
*/
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
Set_invalidflag();
Sgl_makequietnan(resultp1);
Sgl_copytoptr(resultp1,dstptr);
return(NOEXCEPTION);
}
/*
* Check third operand for infinity with a
* sign opposite of the multiply result
*/
if (Sgl_isinfinity(opnd3) &&
(Sgl_sign(resultp1) ^ Sgl_sign(opnd3))) {
/*
* invalid since attempting a magnitude
* subtraction of infinities
*/
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
Set_invalidflag();
Sgl_makequietnan(resultp1);
Sgl_copytoptr(resultp1,dstptr);
return(NOEXCEPTION);
}
/*
* return infinity
*/
Sgl_setinfinity_exponentmantissa(resultp1);
Sgl_copytoptr(resultp1,dstptr);
return(NOEXCEPTION);
}
}
else {
/*
* is NaN; signaling or quiet?
*/
if (Sgl_isone_signaling(opnd1)) {
/* trap if INVALIDTRAP enabled */
if (Is_invalidtrap_enabled())
return(OPC_2E_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(OPC_2E_INVALIDEXCEPTION);
/* make NaN quiet */
Set_invalidflag();
Sgl_set_quiet(opnd2);
Sgl_copytoptr(opnd2,dstptr);
return(NOEXCEPTION);
}
/*
* is third operand a signaling NaN?
*/
else if (Sgl_is_signalingnan(opnd3)) {
/* trap if INVALIDTRAP enabled */
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
/* make NaN quiet */
Set_invalidflag();
Sgl_set_quiet(opnd3);
Sgl_copytoptr(opnd3,dstptr);
return(NOEXCEPTION);
}
/*
* return quiet NaN
*/
Sgl_copytoptr(opnd1,dstptr);
return(NOEXCEPTION);
}
}
/*
* check second operand for NaN's or infinity
*/
if (Sgl_isinfinity_exponent(opnd2)) {
if (Sgl_iszero_mantissa(opnd2)) {
if (Sgl_isnotnan(opnd3)) {
if (Sgl_iszero_exponentmantissa(opnd1)) {
/*
* invalid since multiply operands are
* zero & infinity
*/
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
Set_invalidflag();
Sgl_makequietnan(opnd2);
Sgl_copytoptr(opnd2,dstptr);
return(NOEXCEPTION);
}
/*
* Check third operand for infinity with a
* sign opposite of the multiply result
*/
if (Sgl_isinfinity(opnd3) &&
(Sgl_sign(resultp1) ^ Sgl_sign(opnd3))) {
/*
* invalid since attempting a magnitude
* subtraction of infinities
*/
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
Set_invalidflag();
Sgl_makequietnan(resultp1);
Sgl_copytoptr(resultp1,dstptr);
return(NOEXCEPTION);
}
/*
* return infinity
*/
Sgl_setinfinity_exponentmantissa(resultp1);
Sgl_copytoptr(resultp1,dstptr);
return(NOEXCEPTION);
}
}
else {
/*
* is NaN; signaling or quiet?
*/
if (Sgl_isone_signaling(opnd2)) {
/* trap if INVALIDTRAP enabled */
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
/* make NaN quiet */
Set_invalidflag();
Sgl_set_quiet(opnd2);
}
/*
* is third operand a signaling NaN?
*/
else if (Sgl_is_signalingnan(opnd3)) {
/* trap if INVALIDTRAP enabled */
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
/* make NaN quiet */
Set_invalidflag();
Sgl_set_quiet(opnd3);
Sgl_copytoptr(opnd3,dstptr);
return(NOEXCEPTION);
}
/*
* return quiet NaN
*/
Sgl_copytoptr(opnd2,dstptr);
return(NOEXCEPTION);
}
}
/*
* check third operand for NaN's or infinity
*/
if (Sgl_isinfinity_exponent(opnd3)) {
if (Sgl_iszero_mantissa(opnd3)) {
/* return infinity */
Sgl_copytoptr(opnd3,dstptr);
return(NOEXCEPTION);
} else {
/*
* is NaN; signaling or quiet?
*/
if (Sgl_isone_signaling(opnd3)) {
/* trap if INVALIDTRAP enabled */
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
/* make NaN quiet */
Set_invalidflag();
Sgl_set_quiet(opnd3);
}
/*
* return quiet NaN
*/
Sgl_copytoptr(opnd3,dstptr);
return(NOEXCEPTION);
}
}
/*
* Generate multiply mantissa
*/
if (Sgl_isnotzero_exponent(opnd1)) {
/* set hidden bit */
Sgl_clear_signexponent_set_hidden(opnd1);
}
else {
/* check for zero */
if (Sgl_iszero_mantissa(opnd1)) {
/*
* Perform the add opnd3 with zero here.
*/
if (Sgl_iszero_exponentmantissa(opnd3)) {
if (Is_rounding_mode(ROUNDMINUS)) {
Sgl_or_signs(opnd3,resultp1);
} else {
Sgl_and_signs(opnd3,resultp1);
}
}
/*
* Now let's check for trapped underflow case.
*/
else if (Sgl_iszero_exponent(opnd3) &&
Is_underflowtrap_enabled()) {
/* need to normalize results mantissa */
sign_save = Sgl_signextendedsign(opnd3);
result_exponent = 0;
Sgl_leftshiftby1(opnd3);
Sgl_normalize(opnd3,result_exponent);
Sgl_set_sign(opnd3,/*using*/sign_save);
Sgl_setwrapped_exponent(opnd3,result_exponent,
unfl);
Sgl_copytoptr(opnd3,dstptr);
/* inexact = FALSE */
return(OPC_2E_UNDERFLOWEXCEPTION);
}
Sgl_copytoptr(opnd3,dstptr);
return(NOEXCEPTION);
}
/* is denormalized, adjust exponent */
Sgl_clear_signexponent(opnd1);
Sgl_leftshiftby1(opnd1);
Sgl_normalize(opnd1,mpy_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)) {
/*
* Perform the add opnd3 with zero here.
*/
if (Sgl_iszero_exponentmantissa(opnd3)) {
if (Is_rounding_mode(ROUNDMINUS)) {
Sgl_or_signs(opnd3,resultp1);
} else {
Sgl_and_signs(opnd3,resultp1);
}
}
/*
* Now let's check for trapped underflow case.
*/
else if (Sgl_iszero_exponent(opnd3) &&
Is_underflowtrap_enabled()) {
/* need to normalize results mantissa */
sign_save = Sgl_signextendedsign(opnd3);
result_exponent = 0;
Sgl_leftshiftby1(opnd3);
Sgl_normalize(opnd3,result_exponent);
Sgl_set_sign(opnd3,/*using*/sign_save);
Sgl_setwrapped_exponent(opnd3,result_exponent,
unfl);
Sgl_copytoptr(opnd3,dstptr);
/* inexact = FALSE */
return(OPC_2E_UNDERFLOWEXCEPTION);
}
Sgl_copytoptr(opnd3,dstptr);
return(NOEXCEPTION);
}
/* is denormalized; want to normalize */
Sgl_clear_signexponent(opnd2);
Sgl_leftshiftby1(opnd2);
Sgl_normalize(opnd2,mpy_exponent);
}
/* Multiply the first two source mantissas together */
/*
* The intermediate result will be kept in tmpres,
* which needs enough room for 106 bits of mantissa,
* so lets call it a Double extended.
*/
Sglext_setzero(tmpresp1,tmpresp2);
/*
* Four bits at a time are inspected in each loop, and a
* simple shift and add multiply algorithm is used.
*/
for (count = SGL_P-1; count >= 0; count -= 4) {
Sglext_rightshiftby4(tmpresp1,tmpresp2);
if (Sbit28(opnd1)) {
/* Twoword_add should be an ADD followed by 2 ADDC's */
Twoword_add(tmpresp1, tmpresp2, opnd2<<3, 0);
}
if (Sbit29(opnd1)) {
Twoword_add(tmpresp1, tmpresp2, opnd2<<2, 0);
}
if (Sbit30(opnd1)) {
Twoword_add(tmpresp1, tmpresp2, opnd2<<1, 0);
}
if (Sbit31(opnd1)) {
Twoword_add(tmpresp1, tmpresp2, opnd2, 0);
}
Sgl_rightshiftby4(opnd1);
}
if (Is_sexthiddenoverflow(tmpresp1)) {
/* result mantissa >= 2 (mantissa overflow) */
mpy_exponent++;
Sglext_rightshiftby4(tmpresp1,tmpresp2);
} else {
Sglext_rightshiftby3(tmpresp1,tmpresp2);
}
/*
* Restore the sign of the mpy result which was saved in resultp1.
* The exponent will continue to be kept in mpy_exponent.
*/
Sglext_set_sign(tmpresp1,Sgl_sign(resultp1));
/*
* No rounding is required, since the result of the multiply
* is exact in the extended format.
*/
/*
* Now we are ready to perform the add portion of the operation.
*
* The exponents need to be kept as integers for now, since the
* multiply result might not fit into the exponent field. We
* can't overflow or underflow because of this yet, since the
* add could bring the final result back into range.
*/
add_exponent = Sgl_exponent(opnd3);
/*
* Check for denormalized or zero add operand.
*/
if (add_exponent == 0) {
/* check for zero */
if (Sgl_iszero_mantissa(opnd3)) {
/* right is zero */
/* Left can't be zero and must be result.
*
* The final result is now in tmpres and mpy_exponent,
* and needs to be rounded and squeezed back into
* double precision format from double extended.
*/
result_exponent = mpy_exponent;
Sglext_copy(tmpresp1,tmpresp2,resultp1,resultp2);
sign_save = Sgl_signextendedsign(resultp1);/*save sign*/
goto round;
}
/*
* Neither are zeroes.
* Adjust exponent and normalize add operand.
*/
sign_save = Sgl_signextendedsign(opnd3); /* save sign */
Sgl_clear_signexponent(opnd3);
Sgl_leftshiftby1(opnd3);
Sgl_normalize(opnd3,add_exponent);
Sgl_set_sign(opnd3,sign_save); /* restore sign */
} else {
Sgl_clear_exponent_set_hidden(opnd3);
}
/*
* Copy opnd3 to the double extended variable called right.
*/
Sgl_copyto_sglext(opnd3,rightp1,rightp2);
/*
* A zero "save" helps discover equal operands (for later),
* and is used in swapping operands (if needed).
*/
Sglext_xortointp1(tmpresp1,rightp1,/*to*/save);
/*
* Compare magnitude of operands.
*/
Sglext_copytoint_exponentmantissa(tmpresp1,signlessleft1);
Sglext_copytoint_exponentmantissa(rightp1,signlessright1);
if (mpy_exponent < add_exponent || mpy_exponent == add_exponent &&
Sglext_ismagnitudeless(signlessleft1,signlessright1)) {
/*
* Set the left operand to the larger one by XOR swap.
* First finish the first word "save".
*/
Sglext_xorfromintp1(save,rightp1,/*to*/rightp1);
Sglext_xorfromintp1(save,tmpresp1,/*to*/tmpresp1);
Sglext_swap_lower(tmpresp2,rightp2);
/* also setup exponents used in rest of routine */
diff_exponent = add_exponent - mpy_exponent;
result_exponent = add_exponent;
} else {
/* also setup exponents used in rest of routine */
diff_exponent = mpy_exponent - add_exponent;
result_exponent = mpy_exponent;
}
/* Invariant: left is not smaller than right. */
/*
* Special case alignment of operands that would force alignment
* beyond the extent of the extension. A further optimization
* could special case this but only reduces the path length for
* this infrequent case.
*/
if (diff_exponent > SGLEXT_THRESHOLD) {
diff_exponent = SGLEXT_THRESHOLD;
}
/* Align right operand by shifting it to the right */
Sglext_clear_sign(rightp1);
Sglext_right_align(rightp1,rightp2,/*shifted by*/diff_exponent);
/* Treat sum and difference of the operands separately. */
if ((int)save < 0) {
/*
* Difference of the two operands. Overflow can occur if the
* multiply overflowed. A borrow can occur out of the hidden
* bit and force a post normalization phase.
*/
Sglext_subtract(tmpresp1,tmpresp2, rightp1,rightp2,
resultp1,resultp2);
sign_save = Sgl_signextendedsign(resultp1);
if (Sgl_iszero_hidden(resultp1)) {
/* Handle normalization */
/* A straightforward algorithm would now shift the
* result and extension left until the hidden bit
* becomes one. Not all of the extension bits need
* participate in the shift. Only the two most
* significant bits (round and guard) are needed.
* If only a single shift is needed then the guard
* bit becomes a significant low order bit and the
* extension must participate in the rounding.
* If more than a single shift is needed, then all
* bits to the right of the guard bit are zeros,
* and the guard bit may or may not be zero. */
Sglext_leftshiftby1(resultp1,resultp2);
/* Need to check for a zero result. The sign and
* exponent fields have already been zeroed. The more
* efficient test of the full object can be used.
*/
if (Sglext_iszero(resultp1,resultp2)) {
/* Must have been "x-x" or "x+(-x)". */
if (Is_rounding_mode(ROUNDMINUS))
Sgl_setone_sign(resultp1);
Sgl_copytoptr(resultp1,dstptr);
return(NOEXCEPTION);
}
result_exponent--;
/* Look to see if normalization is finished. */
if (Sgl_isone_hidden(resultp1)) {
/* No further normalization is needed */
goto round;
}
/* Discover first one bit to determine shift amount.
* Use a modified binary search. We have already
* shifted the result one position right and still
* not found a one so the remainder of the extension
* must be zero and simplifies rounding. */
/* Scan bytes */
while (Sgl_iszero_hiddenhigh7mantissa(resultp1)) {
Sglext_leftshiftby8(resultp1,resultp2);
result_exponent -= 8;
}
/* Now narrow it down to the nibble */
if (Sgl_iszero_hiddenhigh3mantissa(resultp1)) {
/* The lower nibble contains the
* normalizing one */
Sglext_leftshiftby4(resultp1,resultp2);
result_exponent -= 4;
}
/* Select case where first bit is set (already
* normalized) otherwise select the proper shift. */
jumpsize = Sgl_hiddenhigh3mantissa(resultp1);
if (jumpsize <= 7) switch(jumpsize) {
case 1:
Sglext_leftshiftby3(resultp1,resultp2);
result_exponent -= 3;
break;
case 2:
case 3:
Sglext_leftshiftby2(resultp1,resultp2);
result_exponent -= 2;
break;
case 4:
case 5:
case 6:
case 7:
Sglext_leftshiftby1(resultp1,resultp2);
result_exponent -= 1;
break;
}
} /* end if (hidden...)... */
/* Fall through and round */
} /* end if (save < 0)... */
else {
/* Add magnitudes */
Sglext_addition(tmpresp1,tmpresp2,
rightp1,rightp2, /*to*/resultp1,resultp2);
sign_save = Sgl_signextendedsign(resultp1);
if (Sgl_isone_hiddenoverflow(resultp1)) {
/* Prenormalization required. */
Sglext_arithrightshiftby1(resultp1,resultp2);
result_exponent++;
} /* end if hiddenoverflow... */
} /* end else ...add magnitudes... */
/* Round the result. If the extension and lower two words are
* all zeros, then the result is exact. Otherwise round in the
* correct direction. Underflow is possible. If a postnormalization
* is necessary, then the mantissa is all zeros so no shift is needed.
*/
round:
if (result_exponent <= 0 && !Is_underflowtrap_enabled()) {
Sglext_denormalize(resultp1,resultp2,result_exponent,is_tiny);
}
Sgl_set_sign(resultp1,/*using*/sign_save);
if (Sglext_isnotzero_mantissap2(resultp2)) {
inexact = TRUE;
switch(Rounding_mode()) {
case ROUNDNEAREST: /* The default. */
if (Sglext_isone_highp2(resultp2)) {
/* at least 1/2 ulp */
if (Sglext_isnotzero_low31p2(resultp2) ||
Sglext_isone_lowp1(resultp1)) {
/* either exactly half way and odd or
* more than 1/2ulp */
Sgl_increment(resultp1);
}
}
break;
case ROUNDPLUS:
if (Sgl_iszero_sign(resultp1)) {
/* Round up positive results */
Sgl_increment(resultp1);
}
break;
case ROUNDMINUS:
if (Sgl_isone_sign(resultp1)) {
/* Round down negative results */
Sgl_increment(resultp1);
}
case ROUNDZERO:;
/* truncate is simple */
} /* end switch... */
if (Sgl_isone_hiddenoverflow(resultp1)) result_exponent++;
}
if (result_exponent >= SGL_INFINITY_EXPONENT) {
/* Overflow */
if (Is_overflowtrap_enabled()) {
/*
* Adjust bias of result
*/
Sgl_setwrapped_exponent(resultp1,result_exponent,ovfl);
Sgl_copytoptr(resultp1,dstptr);
if (inexact)
if (Is_inexacttrap_enabled())
return (OPC_2E_OVERFLOWEXCEPTION |
OPC_2E_INEXACTEXCEPTION);
else Set_inexactflag();
return (OPC_2E_OVERFLOWEXCEPTION);
}
inexact = TRUE;
Set_overflowflag();
Sgl_setoverflow(resultp1);
} else if (result_exponent <= 0) { /* underflow case */
if (Is_underflowtrap_enabled()) {
/*
* Adjust bias of result
*/
Sgl_setwrapped_exponent(resultp1,result_exponent,unfl);
Sgl_copytoptr(resultp1,dstptr);
if (inexact)
if (Is_inexacttrap_enabled())
return (OPC_2E_UNDERFLOWEXCEPTION |
OPC_2E_INEXACTEXCEPTION);
else Set_inexactflag();
return(OPC_2E_UNDERFLOWEXCEPTION);
}
else if (inexact && is_tiny) Set_underflowflag();
}
else Sgl_set_exponent(resultp1,result_exponent);
Sgl_copytoptr(resultp1,dstptr);
if (inexact)
if (Is_inexacttrap_enabled()) return(OPC_2E_INEXACTEXCEPTION);
else Set_inexactflag();
return(NOEXCEPTION);
}
/*
* Single Floating-point Multiply Negate Fused Add
*/
sgl_fmpynfadd(src1ptr,src2ptr,src3ptr,status,dstptr)
sgl_floating_point *src1ptr, *src2ptr, *src3ptr, *dstptr;
unsigned int *status;
{
unsigned int opnd1, opnd2, opnd3;
register unsigned int tmpresp1, tmpresp2;
unsigned int rightp1, rightp2;
unsigned int resultp1, resultp2 = 0;
register int mpy_exponent, add_exponent, count;
boolean inexact = FALSE, is_tiny = FALSE;
unsigned int signlessleft1, signlessright1, save;
register int result_exponent, diff_exponent;
int sign_save, jumpsize;
Sgl_copyfromptr(src1ptr,opnd1);
Sgl_copyfromptr(src2ptr,opnd2);
Sgl_copyfromptr(src3ptr,opnd3);
/*
* set sign bit of result of multiply
*/
if (Sgl_sign(opnd1) ^ Sgl_sign(opnd2))
Sgl_setzero(resultp1);
else
Sgl_setnegativezero(resultp1);
/*
* Generate multiply exponent
*/
mpy_exponent = Sgl_exponent(opnd1) + Sgl_exponent(opnd2) - SGL_BIAS;
/*
* check first operand for NaN's or infinity
*/
if (Sgl_isinfinity_exponent(opnd1)) {
if (Sgl_iszero_mantissa(opnd1)) {
if (Sgl_isnotnan(opnd2) && Sgl_isnotnan(opnd3)) {
if (Sgl_iszero_exponentmantissa(opnd2)) {
/*
* invalid since operands are infinity
* and zero
*/
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
Set_invalidflag();
Sgl_makequietnan(resultp1);
Sgl_copytoptr(resultp1,dstptr);
return(NOEXCEPTION);
}
/*
* Check third operand for infinity with a
* sign opposite of the multiply result
*/
if (Sgl_isinfinity(opnd3) &&
(Sgl_sign(resultp1) ^ Sgl_sign(opnd3))) {
/*
* invalid since attempting a magnitude
* subtraction of infinities
*/
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
Set_invalidflag();
Sgl_makequietnan(resultp1);
Sgl_copytoptr(resultp1,dstptr);
return(NOEXCEPTION);
}
/*
* return infinity
*/
Sgl_setinfinity_exponentmantissa(resultp1);
Sgl_copytoptr(resultp1,dstptr);
return(NOEXCEPTION);
}
}
else {
/*
* is NaN; signaling or quiet?
*/
if (Sgl_isone_signaling(opnd1)) {
/* trap if INVALIDTRAP enabled */
if (Is_invalidtrap_enabled())
return(OPC_2E_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(OPC_2E_INVALIDEXCEPTION);
/* make NaN quiet */
Set_invalidflag();
Sgl_set_quiet(opnd2);
Sgl_copytoptr(opnd2,dstptr);
return(NOEXCEPTION);
}
/*
* is third operand a signaling NaN?
*/
else if (Sgl_is_signalingnan(opnd3)) {
/* trap if INVALIDTRAP enabled */
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
/* make NaN quiet */
Set_invalidflag();
Sgl_set_quiet(opnd3);
Sgl_copytoptr(opnd3,dstptr);
return(NOEXCEPTION);
}
/*
* return quiet NaN
*/
Sgl_copytoptr(opnd1,dstptr);
return(NOEXCEPTION);
}
}
/*
* check second operand for NaN's or infinity
*/
if (Sgl_isinfinity_exponent(opnd2)) {
if (Sgl_iszero_mantissa(opnd2)) {
if (Sgl_isnotnan(opnd3)) {
if (Sgl_iszero_exponentmantissa(opnd1)) {
/*
* invalid since multiply operands are
* zero & infinity
*/
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
Set_invalidflag();
Sgl_makequietnan(opnd2);
Sgl_copytoptr(opnd2,dstptr);
return(NOEXCEPTION);
}
/*
* Check third operand for infinity with a
* sign opposite of the multiply result
*/
if (Sgl_isinfinity(opnd3) &&
(Sgl_sign(resultp1) ^ Sgl_sign(opnd3))) {
/*
* invalid since attempting a magnitude
* subtraction of infinities
*/
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
Set_invalidflag();
Sgl_makequietnan(resultp1);
Sgl_copytoptr(resultp1,dstptr);
return(NOEXCEPTION);
}
/*
* return infinity
*/
Sgl_setinfinity_exponentmantissa(resultp1);
Sgl_copytoptr(resultp1,dstptr);
return(NOEXCEPTION);
}
}
else {
/*
* is NaN; signaling or quiet?
*/
if (Sgl_isone_signaling(opnd2)) {
/* trap if INVALIDTRAP enabled */
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
/* make NaN quiet */
Set_invalidflag();
Sgl_set_quiet(opnd2);
}
/*
* is third operand a signaling NaN?
*/
else if (Sgl_is_signalingnan(opnd3)) {
/* trap if INVALIDTRAP enabled */
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
/* make NaN quiet */
Set_invalidflag();
Sgl_set_quiet(opnd3);
Sgl_copytoptr(opnd3,dstptr);
return(NOEXCEPTION);
}
/*
* return quiet NaN
*/
Sgl_copytoptr(opnd2,dstptr);
return(NOEXCEPTION);
}
}
/*
* check third operand for NaN's or infinity
*/
if (Sgl_isinfinity_exponent(opnd3)) {
if (Sgl_iszero_mantissa(opnd3)) {
/* return infinity */
Sgl_copytoptr(opnd3,dstptr);
return(NOEXCEPTION);
} else {
/*
* is NaN; signaling or quiet?
*/
if (Sgl_isone_signaling(opnd3)) {
/* trap if INVALIDTRAP enabled */
if (Is_invalidtrap_enabled())
return(OPC_2E_INVALIDEXCEPTION);
/* make NaN quiet */
Set_invalidflag();
Sgl_set_quiet(opnd3);
}
/*
* return quiet NaN
*/
Sgl_copytoptr(opnd3,dstptr);
return(NOEXCEPTION);
}
}
/*
* Generate multiply mantissa
*/
if (Sgl_isnotzero_exponent(opnd1)) {
/* set hidden bit */
Sgl_clear_signexponent_set_hidden(opnd1);
}
else {
/* check for zero */
if (Sgl_iszero_mantissa(opnd1)) {
/*
* Perform the add opnd3 with zero here.
*/
if (Sgl_iszero_exponentmantissa(opnd3)) {
if (Is_rounding_mode(ROUNDMINUS)) {
Sgl_or_signs(opnd3,resultp1);
} else {
Sgl_and_signs(opnd3,resultp1);
}
}
/*
* Now let's check for trapped underflow case.
*/
else if (Sgl_iszero_exponent(opnd3) &&
Is_underflowtrap_enabled()) {
/* need to normalize results mantissa */
sign_save = Sgl_signextendedsign(opnd3);
result_exponent = 0;
Sgl_leftshiftby1(opnd3);
Sgl_normalize(opnd3,result_exponent);
Sgl_set_sign(opnd3,/*using*/sign_save);
Sgl_setwrapped_exponent(opnd3,result_exponent,
unfl);
Sgl_copytoptr(opnd3,dstptr);
/* inexact = FALSE */
return(OPC_2E_UNDERFLOWEXCEPTION);
}
Sgl_copytoptr(opnd3,dstptr);
return(NOEXCEPTION);
}
/* is denormalized, adjust exponent */
Sgl_clear_signexponent(opnd1);
Sgl_leftshiftby1(opnd1);
Sgl_normalize(opnd1,mpy_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)) {
/*
* Perform the add opnd3 with zero here.
*/
if (Sgl_iszero_exponentmantissa(opnd3)) {
if (Is_rounding_mode(ROUNDMINUS)) {
Sgl_or_signs(opnd3,resultp1);
} else {
Sgl_and_signs(opnd3,resultp1);
}
}
/*
* Now let's check for trapped underflow case.
*/
else if (Sgl_iszero_exponent(opnd3) &&
Is_underflowtrap_enabled()) {
/* need to normalize results mantissa */
sign_save = Sgl_signextendedsign(opnd3);
result_exponent = 0;
Sgl_leftshiftby1(opnd3);
Sgl_normalize(opnd3,result_exponent);
Sgl_set_sign(opnd3,/*using*/sign_save);
Sgl_setwrapped_exponent(opnd3,result_exponent,
unfl);
Sgl_copytoptr(opnd3,dstptr);
/* inexact = FALSE */
return(OPC_2E_UNDERFLOWEXCEPTION);
}
Sgl_copytoptr(opnd3,dstptr);
return(NOEXCEPTION);
}
/* is denormalized; want to normalize */
Sgl_clear_signexponent(opnd2);
Sgl_leftshiftby1(opnd2);
Sgl_normalize(opnd2,mpy_exponent);
}
/* Multiply the first two source mantissas together */
/*
* The intermediate result will be kept in tmpres,
* which needs enough room for 106 bits of mantissa,
* so lets call it a Double extended.
*/
Sglext_setzero(tmpresp1,tmpresp2);
/*
* Four bits at a time are inspected in each loop, and a
* simple shift and add multiply algorithm is used.
*/
for (count = SGL_P-1; count >= 0; count -= 4) {
Sglext_rightshiftby4(tmpresp1,tmpresp2);
if (Sbit28(opnd1)) {
/* Twoword_add should be an ADD followed by 2 ADDC's */
Twoword_add(tmpresp1, tmpresp2, opnd2<<3, 0);
}
if (Sbit29(opnd1)) {
Twoword_add(tmpresp1, tmpresp2, opnd2<<2, 0);
}
if (Sbit30(opnd1)) {
Twoword_add(tmpresp1, tmpresp2, opnd2<<1, 0);
}
if (Sbit31(opnd1)) {
Twoword_add(tmpresp1, tmpresp2, opnd2, 0);
}
Sgl_rightshiftby4(opnd1);
}
if (Is_sexthiddenoverflow(tmpresp1)) {
/* result mantissa >= 2 (mantissa overflow) */
mpy_exponent++;
Sglext_rightshiftby4(tmpresp1,tmpresp2);
} else {
Sglext_rightshiftby3(tmpresp1,tmpresp2);
}
/*
* Restore the sign of the mpy result which was saved in resultp1.
* The exponent will continue to be kept in mpy_exponent.
*/
Sglext_set_sign(tmpresp1,Sgl_sign(resultp1));
/*
* No rounding is required, since the result of the multiply
* is exact in the extended format.
*/
/*
* Now we are ready to perform the add portion of the operation.
*
* The exponents need to be kept as integers for now, since the
* multiply result might not fit into the exponent field. We
* can't overflow or underflow because of this yet, since the
* add could bring the final result back into range.
*/
add_exponent = Sgl_exponent(opnd3);
/*
* Check for denormalized or zero add operand.
*/
if (add_exponent == 0) {
/* check for zero */
if (Sgl_iszero_mantissa(opnd3)) {
/* right is zero */
/* Left can't be zero and must be result.
*
* The final result is now in tmpres and mpy_exponent,
* and needs to be rounded and squeezed back into
* double precision format from double extended.
*/
result_exponent = mpy_exponent;
Sglext_copy(tmpresp1,tmpresp2,resultp1,resultp2);
sign_save = Sgl_signextendedsign(resultp1);/*save sign*/
goto round;
}
/*
* Neither are zeroes.
* Adjust exponent and normalize add operand.
*/
sign_save = Sgl_signextendedsign(opnd3); /* save sign */
Sgl_clear_signexponent(opnd3);
Sgl_leftshiftby1(opnd3);
Sgl_normalize(opnd3,add_exponent);
Sgl_set_sign(opnd3,sign_save); /* restore sign */
} else {
Sgl_clear_exponent_set_hidden(opnd3);
}
/*
* Copy opnd3 to the double extended variable called right.
*/
Sgl_copyto_sglext(opnd3,rightp1,rightp2);
/*
* A zero "save" helps discover equal operands (for later),
* and is used in swapping operands (if needed).
*/
Sglext_xortointp1(tmpresp1,rightp1,/*to*/save);
/*
* Compare magnitude of operands.
*/
Sglext_copytoint_exponentmantissa(tmpresp1,signlessleft1);
Sglext_copytoint_exponentmantissa(rightp1,signlessright1);
if (mpy_exponent < add_exponent || mpy_exponent == add_exponent &&
Sglext_ismagnitudeless(signlessleft1,signlessright1)) {
/*
* Set the left operand to the larger one by XOR swap.
* First finish the first word "save".
*/
Sglext_xorfromintp1(save,rightp1,/*to*/rightp1);
Sglext_xorfromintp1(save,tmpresp1,/*to*/tmpresp1);
Sglext_swap_lower(tmpresp2,rightp2);
/* also setup exponents used in rest of routine */
diff_exponent = add_exponent - mpy_exponent;
result_exponent = add_exponent;
} else {
/* also setup exponents used in rest of routine */
diff_exponent = mpy_exponent - add_exponent;
result_exponent = mpy_exponent;
}
/* Invariant: left is not smaller than right. */
/*
* Special case alignment of operands that would force alignment
* beyond the extent of the extension. A further optimization
* could special case this but only reduces the path length for
* this infrequent case.
*/
if (diff_exponent > SGLEXT_THRESHOLD) {
diff_exponent = SGLEXT_THRESHOLD;
}
/* Align right operand by shifting it to the right */
Sglext_clear_sign(rightp1);
Sglext_right_align(rightp1,rightp2,/*shifted by*/diff_exponent);
/* Treat sum and difference of the operands separately. */
if ((int)save < 0) {
/*
* Difference of the two operands. Overflow can occur if the
* multiply overflowed. A borrow can occur out of the hidden
* bit and force a post normalization phase.
*/
Sglext_subtract(tmpresp1,tmpresp2, rightp1,rightp2,
resultp1,resultp2);
sign_save = Sgl_signextendedsign(resultp1);
if (Sgl_iszero_hidden(resultp1)) {
/* Handle normalization */
/* A straightforward algorithm would now shift the
* result and extension left until the hidden bit
* becomes one. Not all of the extension bits need
* participate in the shift. Only the two most
* significant bits (round and guard) are needed.
* If only a single shift is needed then the guard
* bit becomes a significant low order bit and the
* extension must participate in the rounding.
* If more than a single shift is needed, then all
* bits to the right of the guard bit are zeros,
* and the guard bit may or may not be zero. */
Sglext_leftshiftby1(resultp1,resultp2);
/* Need to check for a zero result. The sign and
* exponent fields have already been zeroed. The more
* efficient test of the full object can be used.
*/
if (Sglext_iszero(resultp1,resultp2)) {
/* Must have been "x-x" or "x+(-x)". */
if (Is_rounding_mode(ROUNDMINUS))
Sgl_setone_sign(resultp1);
Sgl_copytoptr(resultp1,dstptr);
return(NOEXCEPTION);
}
result_exponent--;
/* Look to see if normalization is finished. */
if (Sgl_isone_hidden(resultp1)) {
/* No further normalization is needed */
goto round;
}
/* Discover first one bit to determine shift amount.
* Use a modified binary search. We have already
* shifted the result one position right and still
* not found a one so the remainder of the extension
* must be zero and simplifies rounding. */
/* Scan bytes */
while (Sgl_iszero_hiddenhigh7mantissa(resultp1)) {
Sglext_leftshiftby8(resultp1,resultp2);
result_exponent -= 8;
}
/* Now narrow it down to the nibble */
if (Sgl_iszero_hiddenhigh3mantissa(resultp1)) {
/* The lower nibble contains the
* normalizing one */
Sglext_leftshiftby4(resultp1,resultp2);
result_exponent -= 4;
}
/* Select case where first bit is set (already
* normalized) otherwise select the proper shift. */
jumpsize = Sgl_hiddenhigh3mantissa(resultp1);
if (jumpsize <= 7) switch(jumpsize) {
case 1:
Sglext_leftshiftby3(resultp1,resultp2);
result_exponent -= 3;
break;
case 2:
case 3:
Sglext_leftshiftby2(resultp1,resultp2);
result_exponent -= 2;
break;
case 4:
case 5:
case 6:
case 7:
Sglext_leftshiftby1(resultp1,resultp2);
result_exponent -= 1;
break;
}
} /* end if (hidden...)... */
/* Fall through and round */
} /* end if (save < 0)... */
else {
/* Add magnitudes */
Sglext_addition(tmpresp1,tmpresp2,
rightp1,rightp2, /*to*/resultp1,resultp2);
sign_save = Sgl_signextendedsign(resultp1);
if (Sgl_isone_hiddenoverflow(resultp1)) {
/* Prenormalization required. */
Sglext_arithrightshiftby1(resultp1,resultp2);
result_exponent++;
} /* end if hiddenoverflow... */
} /* end else ...add magnitudes... */
/* Round the result. If the extension and lower two words are
* all zeros, then the result is exact. Otherwise round in the
* correct direction. Underflow is possible. If a postnormalization
* is necessary, then the mantissa is all zeros so no shift is needed.
*/
round:
if (result_exponent <= 0 && !Is_underflowtrap_enabled()) {
Sglext_denormalize(resultp1,resultp2,result_exponent,is_tiny);
}
Sgl_set_sign(resultp1,/*using*/sign_save);
if (Sglext_isnotzero_mantissap2(resultp2)) {
inexact = TRUE;
switch(Rounding_mode()) {
case ROUNDNEAREST: /* The default. */
if (Sglext_isone_highp2(resultp2)) {
/* at least 1/2 ulp */
if (Sglext_isnotzero_low31p2(resultp2) ||
Sglext_isone_lowp1(resultp1)) {
/* either exactly half way and odd or
* more than 1/2ulp */
Sgl_increment(resultp1);
}
}
break;
case ROUNDPLUS:
if (Sgl_iszero_sign(resultp1)) {
/* Round up positive results */
Sgl_increment(resultp1);
}
break;
case ROUNDMINUS:
if (Sgl_isone_sign(resultp1)) {
/* Round down negative results */
Sgl_increment(resultp1);
}
case ROUNDZERO:;
/* truncate is simple */
} /* end switch... */
if (Sgl_isone_hiddenoverflow(resultp1)) result_exponent++;
}
if (result_exponent >= SGL_INFINITY_EXPONENT) {
/* Overflow */
if (Is_overflowtrap_enabled()) {
/*
* Adjust bias of result
*/
Sgl_setwrapped_exponent(resultp1,result_exponent,ovfl);
Sgl_copytoptr(resultp1,dstptr);
if (inexact)
if (Is_inexacttrap_enabled())
return (OPC_2E_OVERFLOWEXCEPTION |
OPC_2E_INEXACTEXCEPTION);
else Set_inexactflag();
return (OPC_2E_OVERFLOWEXCEPTION);
}
inexact = TRUE;
Set_overflowflag();
Sgl_setoverflow(resultp1);
} else if (result_exponent <= 0) { /* underflow case */
if (Is_underflowtrap_enabled()) {
/*
* Adjust bias of result
*/
Sgl_setwrapped_exponent(resultp1,result_exponent,unfl);
Sgl_copytoptr(resultp1,dstptr);
if (inexact)
if (Is_inexacttrap_enabled())
return (OPC_2E_UNDERFLOWEXCEPTION |
OPC_2E_INEXACTEXCEPTION);
else Set_inexactflag();
return(OPC_2E_UNDERFLOWEXCEPTION);
}
else if (inexact && is_tiny) Set_underflowflag();
}
else Sgl_set_exponent(resultp1,result_exponent);
Sgl_copytoptr(resultp1,dstptr);
if (inexact)
if (Is_inexacttrap_enabled()) return(OPC_2E_INEXACTEXCEPTION);
else Set_inexactflag();
return(NOEXCEPTION);
}
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