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/* Software floating-point emulation.
Convert _Decimal128 to signed or unsigned _BitInt.
Copyright (C) 2023 Free Software Foundation, Inc.
This file is part of GCC.
GCC 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 3, or (at your option) any later
version.
GCC 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.
Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.
You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<http://www.gnu.org/licenses/>. */
#include "soft-fp.h"
#include "bitint.h"
#ifdef __BITINT_MAXWIDTH__
extern void __bid_fixtdbitint (UBILtype *, SItype, _Decimal128);
void
__bid_fixtdbitint (UBILtype *r, SItype rprec, _Decimal128 a)
{
FP_DECL_EX;
USItype arprec = rprec < 0 ? -rprec : rprec;
USItype rn = (arprec + BIL_TYPE_SIZE - 1) / BIL_TYPE_SIZE;
union { _Decimal128 d; UDItype u[2]; } u;
UDItype mantissahi, mantissalo, t;
SItype sgn;
SItype exponent;
USItype exp_bits, mant_bits;
UBILtype *pow10v, *resv;
USItype pow10_limbs, res_limbs, min_limbs, mant_limbs, low_zeros;
FP_INIT_EXCEPTIONS;
u.d = a;
mantissahi = u.u[__FLOAT_WORD_ORDER__ != __ORDER_BIG_ENDIAN__];
mantissalo = u.u[__FLOAT_WORD_ORDER__ == __ORDER_BIG_ENDIAN__];
t = mantissahi >> 47;
sgn = (DItype) mantissahi < 0;
if ((t & (3 << 14)) != (3 << 14))
{
mantissahi &= ((((UDItype) 1) << 49) - 1);
exponent = (t >> 2) & 0x3fff;
if (mantissahi > (UDItype) 0x1ed09bead87c0
|| (mantissahi == (UDItype) 0x1ed09bead87c0
&& mantissalo > (UDItype) 0x378d8e63ffffffff))
{
mantissahi = 0;
mantissalo = 0;
}
}
else if ((t & (3 << 12)) != (3 << 12))
{
mantissahi = 0;
mantissalo = 0;
exponent = t & 0x3fff;
}
else
{
FP_SET_EXCEPTION (FP_EX_INVALID
| FP_EX_INVALID_CVI
| ((FP_EX_INVALID_SNAN
&& ((t & 0x800)) != 0)
? FP_EX_INVALID_SNAN : 0));
ovf:
if (!sgn)
__builtin_memset (r, -1, rn * sizeof (UBILtype));
else
__builtin_memset (r, 0, rn * sizeof (UBILtype));
if (sgn ^ (rprec >= 0))
r[BITINT_END (0, rn - 1)]
|= (UBILtype) -1 << ((arprec - 1) % BIL_TYPE_SIZE);
else
r[BITINT_END (0, rn - 1)]
&= ~((UBILtype) -1 << ((arprec - 1) % BIL_TYPE_SIZE));
goto done;
}
exponent -= 6176;
if (mantissahi == 0 && mantissalo == 0)
{
/* Zero (with any exponent). */
zero:
__builtin_memset (r, 0, rn * sizeof (UBILtype));
goto done;
}
if (exponent <= -34)
{
FP_SET_EXCEPTION (FP_EX_INEXACT);
goto zero;
}
if (exponent < 0)
{
UBILtype limbs[4 * 128 / BIL_TYPE_SIZE];
#if BIL_TYPE_SIZE == 64
limbs[BITINT_END (0, 1)] = mantissahi;
limbs[BITINT_END (1, 0)] = mantissalo;
#elif BIL_TYPE_SIZE == 32
limbs[BITINT_END (0, 3)] = mantissahi >> 32;
limbs[BITINT_END (1, 2)] = mantissahi;
limbs[BITINT_END (2, 1)] = mantissalo >> 32;
limbs[BITINT_END (3, 0)] = mantissalo;
#elif
# error Unhandled BIL_TYPE_SIZE
#endif
__bid_pow10bitint (&limbs[128 / BIL_TYPE_SIZE], 128, -exponent);
__divmodbitint4 (&limbs[2 * 128 / BIL_TYPE_SIZE], 128,
&limbs[3 * 128 / BIL_TYPE_SIZE], 128,
&limbs[0], 128, &limbs[128 / BIL_TYPE_SIZE], 128);
UDItype rem;
#if BIL_TYPE_SIZE == 64
mantissahi = limbs[BITINT_END (4, 5)];
mantissalo = limbs[BITINT_END (5, 4)];
rem = limbs[6] | limbs[7];
#elif BIL_TYPE_SIZE == 32
mantissahi = limbs[BITINT_END (8, 11)] << 32;
mantissahi |= limbs[BITINT_END (9, 10)];
mantissalo = limbs[BITINT_END (10, 9)] << 32;
mantissalo |= limbs[BITINT_END (11, 8)];
rem = limbs[12] | limbs[13] | limbs[14] | limbs[15];
#endif
if (rem)
FP_SET_EXCEPTION (FP_EX_INEXACT);
if (mantissahi == 0 && mantissalo == 0)
goto zero;
exponent = 0;
}
if (rprec >= 0 && sgn)
{
ovf_ex:
FP_SET_EXCEPTION (FP_EX_INVALID | FP_EX_INVALID_CVI);
goto ovf;
}
/* Lower estimate for number of bits needed for pow10 (exponent). */
exp_bits = exponent / 3;
exp_bits = exp_bits * 10 - exp_bits / 29;
if (mantissahi)
mant_bits = sizeof (0ULL) * __CHAR_BIT__ - __builtin_clzll (mantissahi)
+ 64;
else
mant_bits = sizeof (0ULL) * __CHAR_BIT__ - __builtin_clzll (mantissalo);
if (exp_bits + mant_bits > arprec + 1)
goto ovf_ex;
/* Upper estimate for number of bits needed for pow10 (exponent). */
exp_bits = (exponent + 2) / 3;
exp_bits = exp_bits * 10 - exp_bits / 30;
if (exp_bits == 0)
exp_bits = 1;
pow10_limbs = (exp_bits + BIL_TYPE_SIZE - 1) / BIL_TYPE_SIZE;
pow10v = __builtin_alloca (pow10_limbs * sizeof (UBILtype));
low_zeros = __bid_pow10bitint (pow10v, exp_bits, exponent);
res_limbs = ((exp_bits + mant_bits + BIL_TYPE_SIZE - 1)
/ BIL_TYPE_SIZE) - low_zeros;
mant_limbs = (mant_bits + BIL_TYPE_SIZE - 1) / BIL_TYPE_SIZE;
resv = __builtin_alloca ((res_limbs + mant_limbs) * sizeof (UBILtype));
#if BIL_TYPE_SIZE >= 64
if (mant_limbs == 1)
resv[res_limbs] = mantissalo;
else
{
resv[res_limbs + BITINT_END (1, 0)] = mantissalo;
resv[res_limbs + BITINT_END (0, 1)] = mantissahi;
}
#else
resv[res_limbs + BITINT_END (mant_limbs - 1, 0)] = mantissalo;
if (mant_limbs >= 2)
{
resv[res_limbs + BITINT_END (mant_limbs - 2, 1)] = mantissalo >> 32;
if (mant_limbs >= 3)
{
resv[res_limbs + BITINT_END (mant_limbs - 3, 2)] = mantissahi;
if (mant_limbs == 4)
resv[res_limbs + BITINT_END (0, 3)] = mantissahi >> 32;
}
}
#endif
__mulbitint3 (resv, exp_bits + mant_bits - low_zeros * BIL_TYPE_SIZE,
resv + res_limbs, mant_bits,
pow10v + BITINT_END (0, low_zeros),
exp_bits - low_zeros * BIL_TYPE_SIZE);
if (res_limbs + low_zeros >= rn)
{
if (res_limbs + low_zeros > rn && resv[BITINT_END (0, res_limbs - 1)])
goto ovf_ex;
if ((arprec % BIL_TYPE_SIZE) != 0
&& (resv[BITINT_END (rn - res_limbs, rn - 1) - low_zeros]
& ((UBILtype) -1 << (arprec % BIL_TYPE_SIZE))) != 0)
goto ovf_ex;
min_limbs = rn - low_zeros;
}
else
min_limbs = res_limbs;
if (low_zeros)
__builtin_memset (r + BITINT_END (rn - low_zeros, 0), '\0',
low_zeros * sizeof (UBILtype));
if (sgn)
bitint_negate (r + BITINT_END (rn - low_zeros - 1, low_zeros),
resv + BITINT_END (res_limbs - 1, 0), min_limbs);
else
__builtin_memcpy (r + BITINT_END (rn - low_zeros - min_limbs, low_zeros),
resv + BITINT_END (res_limbs - min_limbs, 0),
min_limbs * sizeof (UBILtype));
if (res_limbs + low_zeros < rn)
{
if (sgn)
__builtin_memset (r + BITINT_END (0, res_limbs + low_zeros), -1,
(rn - res_limbs - low_zeros) * sizeof (UBILtype));
else
__builtin_memset (r + BITINT_END (0, res_limbs + low_zeros), '\0',
(rn - res_limbs - low_zeros) * sizeof (UBILtype));
}
else if (sgn)
{
if ((r[BITINT_END (0, rn - 1)]
& ((UBILtype) 1 << ((arprec - 1) % BIL_TYPE_SIZE))) == 0)
goto ovf_ex;
}
else if (rprec < 0
&& (r[BITINT_END (0, rn - 1)]
& ((UBILtype) 1 << ((arprec - 1) % BIL_TYPE_SIZE))) != 0)
goto ovf_ex;
done:
FP_HANDLE_EXCEPTIONS;
}
#endif
|
