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gcc/libgcc/config/libbid/bid64_to_bid128.c
Richard Sandiford 5d5bf77569 Update copyright in libgcc. 
From-SVN: r195731
2013-02-04 19:06:20 +00:00

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/* Copyright (C) 2007-2013 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/>. */
#define BID_128RES
#include "bid_internal.h"
/*
* Takes a BID64 as input and converts it to a BID128 and returns it.
*/
TYPE0_FUNCTION_ARGTYPE1_NORND (UINT128, bid64_to_bid128, UINT64, x)
UINT128 new_coeff, res;
UINT64 sign_x;
int exponent_x;
UINT64 coefficient_x;
if (!unpack_BID64 (&sign_x, &exponent_x, &coefficient_x, x)) {
if (((x) << 1) >= 0xf000000000000000ull) {
#ifdef SET_STATUS_FLAGS
if (((x) & SNAN_MASK64) == SNAN_MASK64) // sNaN
__set_status_flags (pfpsf, INVALID_EXCEPTION);
#endif
res.w[0] = (coefficient_x & 0x0003ffffffffffffull);
__mul_64x64_to_128 (res, res.w[0], power10_table_128[18].w[0]);
res.w[1] |= ((coefficient_x) & 0xfc00000000000000ull);
BID_RETURN (res);
}
}
new_coeff.w[0] = coefficient_x;
new_coeff.w[1] = 0;
get_BID128_very_fast (&res, sign_x,
exponent_x + DECIMAL_EXPONENT_BIAS_128 -
DECIMAL_EXPONENT_BIAS, new_coeff);
BID_RETURN (res);
} // convert_bid64_to_bid128
/*
* Takes a BID128 as input and converts it to a BID64 and returns it.
*/
#if DECIMAL_CALL_BY_REFERENCE
void
bid128_to_bid64 (UINT64 * pres,
UINT128 *
px _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
_EXC_INFO_PARAM) {
UINT128 x = *px;
#else
UINT64
bid128_to_bid64 (UINT128 x _RND_MODE_PARAM _EXC_FLAGS_PARAM
_EXC_MASKS_PARAM _EXC_INFO_PARAM) {
#endif
UINT128 CX, T128, TP128, Qh, Ql, Qh1, Stemp, Tmp, Tmp1, CX1;
UINT64 sign_x, carry, cy, res;
SINT64 D;
int_float f64, fx;
int exponent_x, extra_digits, amount, bin_expon_cx;
unsigned rmode, status, uf_check = 0;
#if DECIMAL_CALL_BY_REFERENCE
#if !DECIMAL_GLOBAL_ROUNDING
_IDEC_round rnd_mode = *prnd_mode;
#endif
#endif
BID_SWAP128 (x);
// unpack arguments, check for NaN or Infinity or 0
if (!unpack_BID128_value (&sign_x, &exponent_x, &CX, x)) {
if ((x.w[1] << 1) >= 0xf000000000000000ull) {
Tmp.w[1] = (CX.w[1] & 0x00003fffffffffffull);
Tmp.w[0] = CX.w[0];
TP128 = reciprocals10_128[18];
__mul_128x128_full (Qh, Ql, Tmp, TP128);
amount = recip_scale[18];
__shr_128 (Tmp, Qh, amount);
res = (CX.w[1] & 0xfc00000000000000ull) | Tmp.w[0];
#ifdef SET_STATUS_FLAGS
if ((x.w[1] & SNAN_MASK64) == SNAN_MASK64) // sNaN
__set_status_flags (pfpsf, INVALID_EXCEPTION);
#endif
BID_RETURN_VAL (res);
}
exponent_x =
exponent_x - DECIMAL_EXPONENT_BIAS_128 + DECIMAL_EXPONENT_BIAS;
if (exponent_x < 0) {
res = sign_x;
BID_RETURN_VAL (res);
}
if (exponent_x > DECIMAL_MAX_EXPON_64)
exponent_x = DECIMAL_MAX_EXPON_64;
res = sign_x | (((UINT64) exponent_x) << 53);
BID_RETURN_VAL (res);
}
if (CX.w[1] || (CX.w[0] >= 10000000000000000ull)) {
// find number of digits in coefficient
// 2^64
f64.i = 0x5f800000;
// fx ~ CX
fx.d = (float) CX.w[1] * f64.d + (float) CX.w[0];
bin_expon_cx = ((fx.i >> 23) & 0xff) - 0x7f;
extra_digits = estimate_decimal_digits[bin_expon_cx] - 16;
// scale = 38-estimate_decimal_digits[bin_expon_cx];
D = CX.w[1] - power10_index_binexp_128[bin_expon_cx].w[1];
if (D > 0
|| (!D
&& CX.w[0] >= power10_index_binexp_128[bin_expon_cx].w[0]))
extra_digits++;
exponent_x += extra_digits;
#ifndef IEEE_ROUND_NEAREST_TIES_AWAY
#ifndef IEEE_ROUND_NEAREST
rmode = rnd_mode;
if (sign_x && (unsigned) (rmode - 1) < 2)
rmode = 3 - rmode;
#else
rmode = 0;
#endif
#else
rmode = 0;
#endif
if (exponent_x < DECIMAL_EXPONENT_BIAS_128 - DECIMAL_EXPONENT_BIAS) {
uf_check = 1;
if (-extra_digits + exponent_x - DECIMAL_EXPONENT_BIAS_128 +
DECIMAL_EXPONENT_BIAS + 35 >= 0) {
if (exponent_x ==
DECIMAL_EXPONENT_BIAS_128 - DECIMAL_EXPONENT_BIAS - 1) {
T128 = round_const_table_128[rmode][extra_digits];
__add_carry_out (CX1.w[0], carry, T128.w[0], CX.w[0]);
CX1.w[1] = CX.w[1] + T128.w[1] + carry;
if (__unsigned_compare_ge_128
(CX1, power10_table_128[extra_digits + 16]))
uf_check = 0;
}
extra_digits =
extra_digits + DECIMAL_EXPONENT_BIAS_128 -
DECIMAL_EXPONENT_BIAS - exponent_x;
exponent_x = DECIMAL_EXPONENT_BIAS_128 - DECIMAL_EXPONENT_BIAS;
//uf_check = 2;
} else
rmode = ROUNDING_TO_ZERO;
}
T128 = round_const_table_128[rmode][extra_digits];
__add_carry_out (CX.w[0], carry, T128.w[0], CX.w[0]);
CX.w[1] = CX.w[1] + T128.w[1] + carry;
TP128 = reciprocals10_128[extra_digits];
__mul_128x128_full (Qh, Ql, CX, TP128);
amount = recip_scale[extra_digits];
if (amount >= 64) {
CX.w[0] = Qh.w[1] >> (amount - 64);
CX.w[1] = 0;
} else {
__shr_128 (CX, Qh, amount);
}
#ifndef IEEE_ROUND_NEAREST_TIES_AWAY
#ifndef IEEE_ROUND_NEAREST
if (!(rmode))
#endif
if (CX.w[0] & 1) {
// check whether fractional part of initial_P/10^ed1 is exactly .5
// get remainder
__shl_128_long (Qh1, Qh, (128 - amount));
if (!Qh1.w[1] && !Qh1.w[0]
&& (Ql.w[1] < reciprocals10_128[extra_digits].w[1]
|| (Ql.w[1] == reciprocals10_128[extra_digits].w[1]
&& Ql.w[0] < reciprocals10_128[extra_digits].w[0]))) {
CX.w[0]--;
}
}
#endif
{
status = INEXACT_EXCEPTION;
// get remainder
__shl_128_long (Qh1, Qh, (128 - amount));
switch (rmode) {
case ROUNDING_TO_NEAREST:
case ROUNDING_TIES_AWAY:
// test whether fractional part is 0
if (Qh1.w[1] == 0x8000000000000000ull && (!Qh1.w[0])
&& (Ql.w[1] < reciprocals10_128[extra_digits].w[1]
|| (Ql.w[1] == reciprocals10_128[extra_digits].w[1]
&& Ql.w[0] < reciprocals10_128[extra_digits].w[0])))
status = EXACT_STATUS;
break;
case ROUNDING_DOWN:
case ROUNDING_TO_ZERO:
if ((!Qh1.w[1]) && (!Qh1.w[0])
&& (Ql.w[1] < reciprocals10_128[extra_digits].w[1]
|| (Ql.w[1] == reciprocals10_128[extra_digits].w[1]
&& Ql.w[0] < reciprocals10_128[extra_digits].w[0])))
status = EXACT_STATUS;
break;
default:
// round up
__add_carry_out (Stemp.w[0], cy, Ql.w[0],
reciprocals10_128[extra_digits].w[0]);
__add_carry_in_out (Stemp.w[1], carry, Ql.w[1],
reciprocals10_128[extra_digits].w[1], cy);
__shr_128_long (Qh, Qh1, (128 - amount));
Tmp.w[0] = 1;
Tmp.w[1] = 0;
__shl_128_long (Tmp1, Tmp, amount);
Qh.w[0] += carry;
if (Qh.w[0] < carry)
Qh.w[1]++;
if (__unsigned_compare_ge_128 (Qh, Tmp1))
status = EXACT_STATUS;
}
if (status != EXACT_STATUS) {
if (uf_check)
status |= UNDERFLOW_EXCEPTION;
#ifdef SET_STATUS_FLAGS
__set_status_flags (pfpsf, status);
#endif
}
}
}
res =
get_BID64 (sign_x,
exponent_x - DECIMAL_EXPONENT_BIAS_128 +
DECIMAL_EXPONENT_BIAS, CX.w[0], rnd_mode, pfpsf);
BID_RETURN_VAL (res);
}
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