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Diffstat (limited to 'math/fromfp.h')
| -rw-r--r-- | math/fromfp.h | 174 |
1 files changed, 0 insertions, 174 deletions
diff --git a/math/fromfp.h b/math/fromfp.h deleted file mode 100644 index db60a00491..0000000000 --- a/math/fromfp.h +++ /dev/null @@ -1,174 +0,0 @@ -/* Round to integer type. Common helper functions. - Copyright (C) 2016-2017 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library 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 - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, see - <http://www.gnu.org/licenses/>. */ - -#include <errno.h> -#include <fenv.h> -#include <float.h> -#include <math.h> -#include <math_private.h> -#include <stdbool.h> -#include <stdint.h> - -/* The including file should have defined UNSIGNED to 0 (signed return - type) or 1 (unsigned return type), INEXACT to 0 (no inexact - exceptions) or 1 (raise inexact exceptions) and RET_TYPE to the - return type (intmax_t or uintmax_t). */ - -/* Return the maximum unbiased exponent for an argument (negative if - NEGATIVE is set) that might be in range for a call to a fromfp - function with width WIDTH (greater than 0, and not exceeding that - of intmax_t). The truncated argument may still be out of range in - the case of negative arguments, and if not out of range it may - become out of range as a result of rounding. */ - -static int -fromfp_max_exponent (bool negative, int width) -{ - if (UNSIGNED) - return negative ? -1 : width - 1; - else - return negative ? width - 1 : width - 2; -} - -/* Return the result of rounding an integer value X (passed as the - absolute value; NEGATIVE is true if the value is negative), where - HALF_BIT is true if the bit with value 0.5 is set and MORE_BITS is - true if any lower bits are set, in the rounding direction - ROUND. */ - -static uintmax_t -fromfp_round (bool negative, uintmax_t x, bool half_bit, bool more_bits, - int round) -{ - switch (round) - { - case FP_INT_UPWARD: - return x + (!negative && (half_bit || more_bits)); - - case FP_INT_DOWNWARD: - return x + (negative && (half_bit || more_bits)); - - case FP_INT_TOWARDZERO: - default: - /* Unknown rounding directions are defined to mean unspecified - rounding; treat this as truncation. */ - return x; - - case FP_INT_TONEARESTFROMZERO: - return x + half_bit; - - case FP_INT_TONEAREST: - return x + (half_bit && ((x & 1) || more_bits)); - } -} - -/* Integer rounding, of a value whose exponent EXPONENT did not exceed - the maximum exponent MAX_EXPONENT and so did not necessarily - overflow, has produced X (possibly wrapping to 0); the sign is - negative if NEGATIVE is true. Return whether this overflowed the - allowed width. */ - -static bool -fromfp_overflowed (bool negative, uintmax_t x, int exponent, int max_exponent) -{ - if (UNSIGNED) - { - if (negative) - return x != 0; - else if (max_exponent == INTMAX_WIDTH - 1) - return exponent == INTMAX_WIDTH - 1 && x == 0; - else - return x == (1ULL << (max_exponent + 1)); - } - else - { - if (negative) - return exponent == max_exponent && x != (1ULL << max_exponent); - else - return x == (1ULL << (max_exponent + 1)); - } -} - -/* Handle a domain error for a call to a fromfp function with an - argument which is negative if NEGATIVE is set, and specified width - (not exceeding that of intmax_t) WIDTH. The return value is - unspecified (with it being unclear if the result needs to fit - within WIDTH bits in this case); we choose to saturate to the given - number of bits (treating NaNs like any other value). */ - -static RET_TYPE -fromfp_domain_error (bool negative, unsigned int width) -{ - feraiseexcept (FE_INVALID); - __set_errno (EDOM); - /* The return value is unspecified; we choose to saturate to the - given number of bits (treating NaNs like any other value). */ - if (UNSIGNED) - { - if (negative) - return 0; - else if (width == INTMAX_WIDTH) - return -1; - else - return (1ULL << width) - 1; - } - else - { - if (width == 0) - return 0; - else if (negative) - return -(1ULL << (width - 1)); - else - return (1ULL << (width - 1)) - 1; - } -} - -/* Given X, the absolute value of a floating-point number (negative if - NEGATIVE is set) truncated towards zero, where HALF_BIT is true if - the bit with value 0.5 is set and MORE_BITS is true if any lower - bits are set, round it in the rounding direction ROUND, handle - errors and exceptions and return the appropriate return value for a - fromfp function. X originally had floating-point exponent - EXPONENT, which does not exceed MAX_EXPONENT, the return value from - fromfp_max_exponent with width WIDTH. */ - -static RET_TYPE -fromfp_round_and_return (bool negative, uintmax_t x, bool half_bit, - bool more_bits, int round, int exponent, - int max_exponent, unsigned int width) -{ - uintmax_t uret = fromfp_round (negative, x, half_bit, more_bits, round); - if (fromfp_overflowed (negative, uret, exponent, max_exponent)) - return fromfp_domain_error (negative, width); - - if (INEXACT && (half_bit || more_bits)) - { - /* There is no need for this to use the specific floating-point - type for which this header is included, and there is no need - for this header to know that type at all, so just use float - here. */ - float force_inexact = 1.0f + FLT_MIN; - math_force_eval (force_inexact); - } - if (UNSIGNED) - /* A negative argument not rounding to zero will already have - produced a domain error. */ - return uret; - else - return negative ? -uret : uret; -} |