350 lines
11 KiB
C
350 lines
11 KiB
C
/* Copyright (C) 2007-2013 Free Software Foundation, Inc.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 3, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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#include "bid_internal.h"
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/*****************************************************************************
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* BID64_round_integral_exact
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****************************************************************************/
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#if DECIMAL_CALL_BY_REFERENCE
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void
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bid64_from_int32 (UINT64 * pres,
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int *px _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
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int x = *px;
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#else
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UINT64
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bid64_from_int32 (int x _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
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#endif
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UINT64 res;
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// if integer is negative, put the absolute value
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// in the lowest 32bits of the result
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if ((x & SIGNMASK32) == SIGNMASK32) {
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// negative int32
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x = ~x + 1; // 2's complement of x
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res = (unsigned int) x | 0xb1c0000000000000ull;
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// (exp << 53)) = biased exp. is 0
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} else { // positive int32
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res = x | 0x31c0000000000000ull; // (exp << 53)) = biased exp. is 0
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}
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BID_RETURN (res);
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}
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#if DECIMAL_CALL_BY_REFERENCE
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void
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bid64_from_uint32 (UINT64 * pres, unsigned int *px
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_EXC_MASKS_PARAM _EXC_INFO_PARAM) {
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unsigned int x = *px;
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#else
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UINT64
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bid64_from_uint32 (unsigned int x _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
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#endif
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UINT64 res;
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res = x | 0x31c0000000000000ull; // (exp << 53)) = biased exp. is 0
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BID_RETURN (res);
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}
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#if DECIMAL_CALL_BY_REFERENCE
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void
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bid64_from_int64 (UINT64 * pres, SINT64 * px
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_RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
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_EXC_INFO_PARAM) {
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SINT64 x = *px;
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#if !DECIMAL_GLOBAL_ROUNDING
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unsigned int rnd_mode = *prnd_mode;
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#endif
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#else
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UINT64
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bid64_from_int64 (SINT64 x
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_RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
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_EXC_INFO_PARAM) {
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#endif
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UINT64 res;
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UINT64 x_sign, C;
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unsigned int q, ind;
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int incr_exp = 0;
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int is_midpoint_lt_even = 0, is_midpoint_gt_even = 0;
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int is_inexact_lt_midpoint = 0, is_inexact_gt_midpoint = 0;
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x_sign = x & 0x8000000000000000ull;
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// if the integer is negative, use the absolute value
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if (x_sign)
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C = ~((UINT64) x) + 1;
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else
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C = x;
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if (C <= BID64_SIG_MAX) { // |C| <= 10^16-1 and the result is exact
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if (C < 0x0020000000000000ull) { // C < 2^53
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res = x_sign | 0x31c0000000000000ull | C;
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} else { // C >= 2^53
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res =
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x_sign | 0x6c70000000000000ull | (C & 0x0007ffffffffffffull);
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}
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} else { // |C| >= 10^16 and the result may be inexact
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// the smallest |C| is 10^16 which has 17 decimal digits
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// the largest |C| is 0x8000000000000000 = 9223372036854775808 w/ 19 digits
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if (C < 0x16345785d8a0000ull) { // x < 10^17
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q = 17;
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ind = 1; // number of digits to remove for q = 17
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} else if (C < 0xde0b6b3a7640000ull) { // C < 10^18
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q = 18;
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ind = 2; // number of digits to remove for q = 18
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} else { // C < 10^19
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q = 19;
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ind = 3; // number of digits to remove for q = 19
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}
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// overflow and underflow are not possible
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// Note: performace can be improved by inlining this call
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round64_2_18 ( // will work for 19 digits too if C fits in 64 bits
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q, ind, C, &res, &incr_exp,
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&is_midpoint_lt_even, &is_midpoint_gt_even,
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&is_inexact_lt_midpoint, &is_inexact_gt_midpoint);
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if (incr_exp)
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ind++;
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// set the inexact flag
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if (is_inexact_lt_midpoint || is_inexact_gt_midpoint ||
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is_midpoint_lt_even || is_midpoint_gt_even)
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*pfpsf |= INEXACT_EXCEPTION;
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// general correction from RN to RA, RM, RP, RZ; result uses ind for exp
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if (rnd_mode != ROUNDING_TO_NEAREST) {
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if ((!x_sign
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&& ((rnd_mode == ROUNDING_UP && is_inexact_lt_midpoint)
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||
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((rnd_mode == ROUNDING_TIES_AWAY
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|| rnd_mode == ROUNDING_UP) && is_midpoint_gt_even)))
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|| (x_sign
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&& ((rnd_mode == ROUNDING_DOWN && is_inexact_lt_midpoint)
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||
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((rnd_mode == ROUNDING_TIES_AWAY
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|| rnd_mode == ROUNDING_DOWN)
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&& is_midpoint_gt_even)))) {
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res = res + 1;
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if (res == 0x002386f26fc10000ull) { // res = 10^16 => rounding overflow
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res = 0x00038d7ea4c68000ull; // 10^15
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ind = ind + 1;
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}
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} else if ((is_midpoint_lt_even || is_inexact_gt_midpoint) &&
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((x_sign && (rnd_mode == ROUNDING_UP ||
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rnd_mode == ROUNDING_TO_ZERO)) ||
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(!x_sign && (rnd_mode == ROUNDING_DOWN ||
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rnd_mode == ROUNDING_TO_ZERO)))) {
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res = res - 1;
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// check if we crossed into the lower decade
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if (res == 0x00038d7ea4c67fffull) { // 10^15 - 1
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res = 0x002386f26fc0ffffull; // 10^16 - 1
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ind = ind - 1;
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}
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} else {
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; // exact, the result is already correct
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}
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}
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if (res < 0x0020000000000000ull) { // res < 2^53
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res = x_sign | (((UINT64) ind + 398) << 53) | res;
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} else { // res >= 2^53
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res =
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x_sign | 0x6000000000000000ull | (((UINT64) ind + 398) << 51) |
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(res & 0x0007ffffffffffffull);
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}
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}
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BID_RETURN (res);
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}
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#if DECIMAL_CALL_BY_REFERENCE
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void
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bid64_from_uint64 (UINT64 * pres, UINT64 * px
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_RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
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_EXC_INFO_PARAM) {
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UINT64 x = *px;
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#if !DECIMAL_GLOBAL_ROUNDING
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unsigned int rnd_mode = *prnd_mode;
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#endif
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#else
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UINT64
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bid64_from_uint64 (UINT64 x
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_RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
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_EXC_INFO_PARAM) {
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#endif
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UINT64 res;
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UINT128 x128, res128;
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unsigned int q, ind;
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int incr_exp = 0;
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int is_midpoint_lt_even = 0, is_midpoint_gt_even = 0;
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int is_inexact_lt_midpoint = 0, is_inexact_gt_midpoint = 0;
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if (x <= BID64_SIG_MAX) { // x <= 10^16-1 and the result is exact
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if (x < 0x0020000000000000ull) { // x < 2^53
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res = 0x31c0000000000000ull | x;
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} else { // x >= 2^53
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res = 0x6c70000000000000ull | (x & 0x0007ffffffffffffull);
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}
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} else { // x >= 10^16 and the result may be inexact
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// the smallest x is 10^16 which has 17 decimal digits
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// the largest x is 0xffffffffffffffff = 18446744073709551615 w/ 20 digits
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if (x < 0x16345785d8a0000ull) { // x < 10^17
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q = 17;
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ind = 1; // number of digits to remove for q = 17
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} else if (x < 0xde0b6b3a7640000ull) { // x < 10^18
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q = 18;
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ind = 2; // number of digits to remove for q = 18
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} else if (x < 0x8ac7230489e80000ull) { // x < 10^19
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q = 19;
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ind = 3; // number of digits to remove for q = 19
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} else { // x < 10^20
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q = 20;
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ind = 4; // number of digits to remove for q = 20
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}
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// overflow and underflow are not possible
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// Note: performace can be improved by inlining this call
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if (q <= 19) {
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round64_2_18 ( // will work for 20 digits too if x fits in 64 bits
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q, ind, x, &res, &incr_exp,
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&is_midpoint_lt_even, &is_midpoint_gt_even,
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&is_inexact_lt_midpoint, &is_inexact_gt_midpoint);
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} else { // q = 20
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x128.w[1] = 0x0;
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x128.w[0] = x;
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round128_19_38 (q, ind, x128, &res128, &incr_exp,
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&is_midpoint_lt_even, &is_midpoint_gt_even,
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&is_inexact_lt_midpoint, &is_inexact_gt_midpoint);
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res = res128.w[0]; // res.w[1] is 0
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}
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if (incr_exp)
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ind++;
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// set the inexact flag
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if (is_inexact_lt_midpoint || is_inexact_gt_midpoint ||
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is_midpoint_lt_even || is_midpoint_gt_even)
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*pfpsf |= INEXACT_EXCEPTION;
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// general correction from RN to RA, RM, RP, RZ; result uses ind for exp
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if (rnd_mode != ROUNDING_TO_NEAREST) {
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if ((rnd_mode == ROUNDING_UP && is_inexact_lt_midpoint) ||
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((rnd_mode == ROUNDING_TIES_AWAY || rnd_mode == ROUNDING_UP)
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&& is_midpoint_gt_even)) {
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res = res + 1;
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if (res == 0x002386f26fc10000ull) { // res = 10^16 => rounding overflow
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res = 0x00038d7ea4c68000ull; // 10^15
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ind = ind + 1;
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}
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} else if ((is_midpoint_lt_even || is_inexact_gt_midpoint) &&
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(rnd_mode == ROUNDING_DOWN ||
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rnd_mode == ROUNDING_TO_ZERO)) {
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res = res - 1;
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// check if we crossed into the lower decade
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if (res == 0x00038d7ea4c67fffull) { // 10^15 - 1
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res = 0x002386f26fc0ffffull; // 10^16 - 1
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ind = ind - 1;
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}
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} else {
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; // exact, the result is already correct
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}
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}
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if (res < 0x0020000000000000ull) { // res < 2^53
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res = (((UINT64) ind + 398) << 53) | res;
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} else { // res >= 2^53
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res = 0x6000000000000000ull | (((UINT64) ind + 398) << 51) |
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(res & 0x0007ffffffffffffull);
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}
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}
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BID_RETURN (res);
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}
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#if DECIMAL_CALL_BY_REFERENCE
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void
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bid128_from_int32 (UINT128 * pres,
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int *px _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
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int x = *px;
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#else
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UINT128
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bid128_from_int32 (int x _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
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#endif
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UINT128 res;
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// if integer is negative, use the absolute value
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if ((x & SIGNMASK32) == SIGNMASK32) {
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res.w[HIGH_128W] = 0xb040000000000000ull;
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res.w[LOW_128W] = ~((unsigned int) x) + 1; // 2's complement of x
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} else {
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res.w[HIGH_128W] = 0x3040000000000000ull;
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res.w[LOW_128W] = (unsigned int) x;
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}
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BID_RETURN (res);
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}
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#if DECIMAL_CALL_BY_REFERENCE
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void
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bid128_from_uint32 (UINT128 * pres, unsigned int *px
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_EXC_MASKS_PARAM _EXC_INFO_PARAM) {
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unsigned int x = *px;
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#else
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UINT128
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bid128_from_uint32 (unsigned int x _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
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#endif
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UINT128 res;
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res.w[HIGH_128W] = 0x3040000000000000ull;
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res.w[LOW_128W] = x;
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BID_RETURN (res);
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}
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#if DECIMAL_CALL_BY_REFERENCE
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void
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bid128_from_int64 (UINT128 * pres, SINT64 * px
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_EXC_MASKS_PARAM _EXC_INFO_PARAM) {
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SINT64 x = *px;
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#else
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UINT128
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bid128_from_int64 (SINT64 x _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
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#endif
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UINT128 res;
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// if integer is negative, use the absolute value
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if ((x & SIGNMASK64) == SIGNMASK64) {
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res.w[HIGH_128W] = 0xb040000000000000ull;
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res.w[LOW_128W] = ~x + 1; // 2's complement of x
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} else {
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res.w[HIGH_128W] = 0x3040000000000000ull;
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res.w[LOW_128W] = x;
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}
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BID_RETURN (res);
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}
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#if DECIMAL_CALL_BY_REFERENCE
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void
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bid128_from_uint64 (UINT128 * pres, UINT64 * px
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_EXC_MASKS_PARAM _EXC_INFO_PARAM) {
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UINT64 x = *px;
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#else
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UINT128
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bid128_from_uint64 (UINT64 x _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
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#endif
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UINT128 res;
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res.w[HIGH_128W] = 0x3040000000000000ull;
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res.w[LOW_128W] = x;
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BID_RETURN (res);
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}
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