OpenE2K
/
gcc
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity
gcc/libgcc/config/libbid/bid_from_int.c

350 lines
11 KiB
C
Raw Blame History

/* Copyright (C) 2007, 2009 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 "bid_internal.h"
/*****************************************************************************
* BID64_round_integral_exact
****************************************************************************/
#if DECIMAL_CALL_BY_REFERENCE
void
bid64_from_int32 (UINT64 * pres,
int *px _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
int x = *px;
#else
UINT64
bid64_from_int32 (int x _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
#endif
UINT64 res;
// if integer is negative, put the absolute value
// in the lowest 32bits of the result
if ((x & SIGNMASK32) == SIGNMASK32) {
// negative int32
x = ~x + 1; // 2's complement of x
res = (unsigned int) x | 0xb1c0000000000000ull;
// (exp << 53)) = biased exp. is 0
} else { // positive int32
res = x | 0x31c0000000000000ull; // (exp << 53)) = biased exp. is 0
}
BID_RETURN (res);
}
#if DECIMAL_CALL_BY_REFERENCE
void
bid64_from_uint32 (UINT64 * pres, unsigned int *px
_EXC_MASKS_PARAM _EXC_INFO_PARAM) {
unsigned int x = *px;
#else
UINT64
bid64_from_uint32 (unsigned int x _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
#endif
UINT64 res;
res = x | 0x31c0000000000000ull; // (exp << 53)) = biased exp. is 0
BID_RETURN (res);
}
#if DECIMAL_CALL_BY_REFERENCE
void
bid64_from_int64 (UINT64 * pres, SINT64 * px
_RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
_EXC_INFO_PARAM) {
SINT64 x = *px;
#if !DECIMAL_GLOBAL_ROUNDING
unsigned int rnd_mode = *prnd_mode;
#endif
#else
UINT64
bid64_from_int64 (SINT64 x
_RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
_EXC_INFO_PARAM) {
#endif
UINT64 res;
UINT64 x_sign, C;
unsigned int q, ind;
int incr_exp = 0;
int is_midpoint_lt_even = 0, is_midpoint_gt_even = 0;
int is_inexact_lt_midpoint = 0, is_inexact_gt_midpoint = 0;
x_sign = x & 0x8000000000000000ull;
// if the integer is negative, use the absolute value
if (x_sign)
C = ~((UINT64) x) + 1;
else
C = x;
if (C <= BID64_SIG_MAX) { // |C| <= 10^16-1 and the result is exact
if (C < 0x0020000000000000ull) { // C < 2^53
res = x_sign | 0x31c0000000000000ull | C;
} else { // C >= 2^53
res =
x_sign | 0x6c70000000000000ull | (C & 0x0007ffffffffffffull);
}
} else { // |C| >= 10^16 and the result may be inexact
// the smallest |C| is 10^16 which has 17 decimal digits
// the largest |C| is 0x8000000000000000 = 9223372036854775808 w/ 19 digits
if (C < 0x16345785d8a0000ull) { // x < 10^17
q = 17;
ind = 1; // number of digits to remove for q = 17
} else if (C < 0xde0b6b3a7640000ull) { // C < 10^18
q = 18;
ind = 2; // number of digits to remove for q = 18
} else { // C < 10^19
q = 19;
ind = 3; // number of digits to remove for q = 19
}
// overflow and underflow are not possible
// Note: performace can be improved by inlining this call
round64_2_18 ( // will work for 19 digits too if C fits in 64 bits
q, ind, C, &res, &incr_exp,
&is_midpoint_lt_even, &is_midpoint_gt_even,
&is_inexact_lt_midpoint, &is_inexact_gt_midpoint);
if (incr_exp)
ind++;
// set the inexact flag
if (is_inexact_lt_midpoint || is_inexact_gt_midpoint ||
is_midpoint_lt_even || is_midpoint_gt_even)
*pfpsf |= INEXACT_EXCEPTION;
// general correction from RN to RA, RM, RP, RZ; result uses ind for exp
if (rnd_mode != ROUNDING_TO_NEAREST) {
if ((!x_sign
&& ((rnd_mode == ROUNDING_UP && is_inexact_lt_midpoint)
||
((rnd_mode == ROUNDING_TIES_AWAY
|| rnd_mode == ROUNDING_UP) && is_midpoint_gt_even)))
|| (x_sign
&& ((rnd_mode == ROUNDING_DOWN && is_inexact_lt_midpoint)
||
((rnd_mode == ROUNDING_TIES_AWAY
|| rnd_mode == ROUNDING_DOWN)
&& is_midpoint_gt_even)))) {
res = res + 1;
if (res == 0x002386f26fc10000ull) { // res = 10^16 => rounding overflow
res = 0x00038d7ea4c68000ull; // 10^15
ind = ind + 1;
}
} else if ((is_midpoint_lt_even || is_inexact_gt_midpoint) &&
((x_sign && (rnd_mode == ROUNDING_UP ||
rnd_mode == ROUNDING_TO_ZERO)) ||
(!x_sign && (rnd_mode == ROUNDING_DOWN ||
rnd_mode == ROUNDING_TO_ZERO)))) {
res = res - 1;
// check if we crossed into the lower decade
if (res == 0x00038d7ea4c67fffull) { // 10^15 - 1
res = 0x002386f26fc0ffffull; // 10^16 - 1
ind = ind - 1;
}
} else {
; // exact, the result is already correct
}
}
if (res < 0x0020000000000000ull) { // res < 2^53
res = x_sign | (((UINT64) ind + 398) << 53) | res;
} else { // res >= 2^53
res =
x_sign | 0x6000000000000000ull | (((UINT64) ind + 398) << 51) |
(res & 0x0007ffffffffffffull);
}
}
BID_RETURN (res);
}
#if DECIMAL_CALL_BY_REFERENCE
void
bid64_from_uint64 (UINT64 * pres, UINT64 * px
_RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
_EXC_INFO_PARAM) {
UINT64 x = *px;
#if !DECIMAL_GLOBAL_ROUNDING
unsigned int rnd_mode = *prnd_mode;
#endif
#else
UINT64
bid64_from_uint64 (UINT64 x
_RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
_EXC_INFO_PARAM) {
#endif
UINT64 res;
UINT128 x128, res128;
unsigned int q, ind;
int incr_exp = 0;
int is_midpoint_lt_even = 0, is_midpoint_gt_even = 0;
int is_inexact_lt_midpoint = 0, is_inexact_gt_midpoint = 0;
if (x <= BID64_SIG_MAX) { // x <= 10^16-1 and the result is exact
if (x < 0x0020000000000000ull) { // x < 2^53
res = 0x31c0000000000000ull | x;
} else { // x >= 2^53
res = 0x6c70000000000000ull | (x & 0x0007ffffffffffffull);
}
} else { // x >= 10^16 and the result may be inexact
// the smallest x is 10^16 which has 17 decimal digits
// the largest x is 0xffffffffffffffff = 18446744073709551615 w/ 20 digits
if (x < 0x16345785d8a0000ull) { // x < 10^17
q = 17;
ind = 1; // number of digits to remove for q = 17
} else if (x < 0xde0b6b3a7640000ull) { // x < 10^18
q = 18;
ind = 2; // number of digits to remove for q = 18
} else if (x < 0x8ac7230489e80000ull) { // x < 10^19
q = 19;
ind = 3; // number of digits to remove for q = 19
} else { // x < 10^20
q = 20;
ind = 4; // number of digits to remove for q = 20
}
// overflow and underflow are not possible
// Note: performace can be improved by inlining this call
if (q <= 19) {
round64_2_18 ( // will work for 20 digits too if x fits in 64 bits
q, ind, x, &res, &incr_exp,
&is_midpoint_lt_even, &is_midpoint_gt_even,
&is_inexact_lt_midpoint, &is_inexact_gt_midpoint);
} else { // q = 20
x128.w[1] = 0x0;
x128.w[0] = x;
round128_19_38 (q, ind, x128, &res128, &incr_exp,
&is_midpoint_lt_even, &is_midpoint_gt_even,
&is_inexact_lt_midpoint, &is_inexact_gt_midpoint);
res = res128.w[0]; // res.w[1] is 0
}
if (incr_exp)
ind++;
// set the inexact flag
if (is_inexact_lt_midpoint || is_inexact_gt_midpoint ||
is_midpoint_lt_even || is_midpoint_gt_even)
*pfpsf |= INEXACT_EXCEPTION;
// general correction from RN to RA, RM, RP, RZ; result uses ind for exp
if (rnd_mode != ROUNDING_TO_NEAREST) {
if ((rnd_mode == ROUNDING_UP && is_inexact_lt_midpoint) ||
((rnd_mode == ROUNDING_TIES_AWAY || rnd_mode == ROUNDING_UP)
&& is_midpoint_gt_even)) {
res = res + 1;
if (res == 0x002386f26fc10000ull) { // res = 10^16 => rounding overflow
res = 0x00038d7ea4c68000ull; // 10^15
ind = ind + 1;
}
} else if ((is_midpoint_lt_even || is_inexact_gt_midpoint) &&
(rnd_mode == ROUNDING_DOWN ||
rnd_mode == ROUNDING_TO_ZERO)) {
res = res - 1;
// check if we crossed into the lower decade
if (res == 0x00038d7ea4c67fffull) { // 10^15 - 1
res = 0x002386f26fc0ffffull; // 10^16 - 1
ind = ind - 1;
}
} else {
; // exact, the result is already correct
}
}
if (res < 0x0020000000000000ull) { // res < 2^53
res = (((UINT64) ind + 398) << 53) | res;
} else { // res >= 2^53
res = 0x6000000000000000ull | (((UINT64) ind + 398) << 51) |
(res & 0x0007ffffffffffffull);
}
}
BID_RETURN (res);
}
#if DECIMAL_CALL_BY_REFERENCE
void
bid128_from_int32 (UINT128 * pres,
int *px _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
int x = *px;
#else
UINT128
bid128_from_int32 (int x _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
#endif
UINT128 res;
// if integer is negative, use the absolute value
if ((x & SIGNMASK32) == SIGNMASK32) {
res.w[HIGH_128W] = 0xb040000000000000ull;
res.w[LOW_128W] = ~((unsigned int) x) + 1; // 2's complement of x
} else {
res.w[HIGH_128W] = 0x3040000000000000ull;
res.w[LOW_128W] = (unsigned int) x;
}
BID_RETURN (res);
}
#if DECIMAL_CALL_BY_REFERENCE
void
bid128_from_uint32 (UINT128 * pres, unsigned int *px
_EXC_MASKS_PARAM _EXC_INFO_PARAM) {
unsigned int x = *px;
#else
UINT128
bid128_from_uint32 (unsigned int x _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
#endif
UINT128 res;
res.w[HIGH_128W] = 0x3040000000000000ull;
res.w[LOW_128W] = x;
BID_RETURN (res);
}
#if DECIMAL_CALL_BY_REFERENCE
void
bid128_from_int64 (UINT128 * pres, SINT64 * px
_EXC_MASKS_PARAM _EXC_INFO_PARAM) {
SINT64 x = *px;
#else
UINT128
bid128_from_int64 (SINT64 x _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
#endif
UINT128 res;
// if integer is negative, use the absolute value
if ((x & SIGNMASK64) == SIGNMASK64) {
res.w[HIGH_128W] = 0xb040000000000000ull;
res.w[LOW_128W] = ~x + 1; // 2's complement of x
} else {
res.w[HIGH_128W] = 0x3040000000000000ull;
res.w[LOW_128W] = x;
}
BID_RETURN (res);
}
#if DECIMAL_CALL_BY_REFERENCE
void
bid128_from_uint64 (UINT128 * pres, UINT64 * px
_EXC_MASKS_PARAM _EXC_INFO_PARAM) {
UINT64 x = *px;
#else
UINT128
bid128_from_uint64 (UINT64 x _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
#endif
UINT128 res;
res.w[HIGH_128W] = 0x3040000000000000ull;
res.w[LOW_128W] = x;
BID_RETURN (res);
}
Reference in New Issue View Git Blame Copy Permalink