371 lines
12 KiB
C
371 lines
12 KiB
C
/* Helper macros for functions returning a narrower type.
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Copyright (C) 2018 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#ifndef _MATH_NARROW_H
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#define _MATH_NARROW_H 1
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#include <bits/floatn.h>
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#include <bits/long-double.h>
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#include <errno.h>
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#include <fenv.h>
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#include <ieee754.h>
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#include <math-barriers.h>
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#include <math_private.h>
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#include <fenv_private.h>
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/* Carry out a computation using round-to-odd. The computation is
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EXPR; the union type in which to store the result is UNION and the
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subfield of the "ieee" field of that union with the low part of the
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mantissa is MANTISSA; SUFFIX is the suffix for the libc_fe* macros
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to ensure that the correct rounding mode is used, for platforms
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with multiple rounding modes where those macros set only the
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relevant mode. This macro does not work correctly if the sign of
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an exact zero result depends on the rounding mode, so that case
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must be checked for separately. */
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#define ROUND_TO_ODD(EXPR, UNION, SUFFIX, MANTISSA) \
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({ \
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fenv_t env; \
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UNION u; \
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\
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libc_feholdexcept_setround ## SUFFIX (&env, FE_TOWARDZERO); \
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u.d = (EXPR); \
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math_force_eval (u.d); \
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u.ieee.MANTISSA \
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|= libc_feupdateenv_test ## SUFFIX (&env, FE_INEXACT) != 0; \
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\
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u.d; \
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})
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/* Check for error conditions from a narrowing add function returning
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RET with arguments X and Y and set errno as needed. Overflow and
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underflow can occur for finite arguments and a domain error for
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infinite ones. */
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#define CHECK_NARROW_ADD(RET, X, Y) \
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do \
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{ \
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if (!isfinite (RET)) \
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{ \
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if (isnan (RET)) \
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{ \
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if (!isnan (X) && !isnan (Y)) \
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__set_errno (EDOM); \
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} \
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else if (isfinite (X) && isfinite (Y)) \
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__set_errno (ERANGE); \
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} \
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else if ((RET) == 0 && (X) != -(Y)) \
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__set_errno (ERANGE); \
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} \
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while (0)
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/* Implement narrowing add using round-to-odd. The arguments are X
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and Y, the return type is TYPE and UNION, MANTISSA and SUFFIX are
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as for ROUND_TO_ODD. */
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#define NARROW_ADD_ROUND_TO_ODD(X, Y, TYPE, UNION, SUFFIX, MANTISSA) \
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do \
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{ \
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TYPE ret; \
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\
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/* Ensure a zero result is computed in the original rounding \
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mode. */ \
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if ((X) == -(Y)) \
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ret = (TYPE) ((X) + (Y)); \
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else \
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ret = (TYPE) ROUND_TO_ODD (math_opt_barrier (X) + (Y), \
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UNION, SUFFIX, MANTISSA); \
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\
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CHECK_NARROW_ADD (ret, (X), (Y)); \
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return ret; \
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} \
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while (0)
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/* Implement a narrowing add function that is not actually narrowing
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or where no attempt is made to be correctly rounding (the latter
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only applies to IBM long double). The arguments are X and Y and
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the return type is TYPE. */
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#define NARROW_ADD_TRIVIAL(X, Y, TYPE) \
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do \
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{ \
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TYPE ret; \
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\
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ret = (TYPE) ((X) + (Y)); \
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CHECK_NARROW_ADD (ret, (X), (Y)); \
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return ret; \
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} \
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while (0)
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/* Check for error conditions from a narrowing subtract function
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returning RET with arguments X and Y and set errno as needed.
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Overflow and underflow can occur for finite arguments and a domain
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error for infinite ones. */
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#define CHECK_NARROW_SUB(RET, X, Y) \
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do \
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{ \
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if (!isfinite (RET)) \
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{ \
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if (isnan (RET)) \
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{ \
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if (!isnan (X) && !isnan (Y)) \
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__set_errno (EDOM); \
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} \
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else if (isfinite (X) && isfinite (Y)) \
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__set_errno (ERANGE); \
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} \
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else if ((RET) == 0 && (X) != (Y)) \
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__set_errno (ERANGE); \
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} \
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while (0)
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/* Implement narrowing subtract using round-to-odd. The arguments are
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X and Y, the return type is TYPE and UNION, MANTISSA and SUFFIX are
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as for ROUND_TO_ODD. */
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#define NARROW_SUB_ROUND_TO_ODD(X, Y, TYPE, UNION, SUFFIX, MANTISSA) \
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do \
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{ \
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TYPE ret; \
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\
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/* Ensure a zero result is computed in the original rounding \
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mode. */ \
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if ((X) == (Y)) \
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ret = (TYPE) ((X) - (Y)); \
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else \
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ret = (TYPE) ROUND_TO_ODD (math_opt_barrier (X) - (Y), \
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UNION, SUFFIX, MANTISSA); \
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\
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CHECK_NARROW_SUB (ret, (X), (Y)); \
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return ret; \
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} \
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while (0)
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/* Implement a narrowing subtract function that is not actually
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narrowing or where no attempt is made to be correctly rounding (the
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latter only applies to IBM long double). The arguments are X and Y
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and the return type is TYPE. */
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#define NARROW_SUB_TRIVIAL(X, Y, TYPE) \
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do \
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{ \
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TYPE ret; \
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\
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ret = (TYPE) ((X) - (Y)); \
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CHECK_NARROW_SUB (ret, (X), (Y)); \
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return ret; \
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} \
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while (0)
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/* Check for error conditions from a narrowing multiply function
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returning RET with arguments X and Y and set errno as needed.
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Overflow and underflow can occur for finite arguments and a domain
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error for Inf * 0. */
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#define CHECK_NARROW_MUL(RET, X, Y) \
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do \
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{ \
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if (!isfinite (RET)) \
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{ \
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if (isnan (RET)) \
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{ \
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if (!isnan (X) && !isnan (Y)) \
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__set_errno (EDOM); \
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} \
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else if (isfinite (X) && isfinite (Y)) \
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__set_errno (ERANGE); \
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} \
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else if ((RET) == 0 && (X) != 0 && (Y) != 0) \
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__set_errno (ERANGE); \
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} \
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while (0)
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/* Implement narrowing multiply using round-to-odd. The arguments are
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X and Y, the return type is TYPE and UNION, MANTISSA and SUFFIX are
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as for ROUND_TO_ODD. */
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#define NARROW_MUL_ROUND_TO_ODD(X, Y, TYPE, UNION, SUFFIX, MANTISSA) \
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do \
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{ \
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TYPE ret; \
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\
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ret = (TYPE) ROUND_TO_ODD (math_opt_barrier (X) * (Y), \
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UNION, SUFFIX, MANTISSA); \
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\
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CHECK_NARROW_MUL (ret, (X), (Y)); \
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return ret; \
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} \
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while (0)
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/* Implement a narrowing multiply function that is not actually
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narrowing or where no attempt is made to be correctly rounding (the
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latter only applies to IBM long double). The arguments are X and Y
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and the return type is TYPE. */
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#define NARROW_MUL_TRIVIAL(X, Y, TYPE) \
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do \
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{ \
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TYPE ret; \
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\
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ret = (TYPE) ((X) * (Y)); \
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CHECK_NARROW_MUL (ret, (X), (Y)); \
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return ret; \
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} \
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while (0)
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/* Check for error conditions from a narrowing divide function
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returning RET with arguments X and Y and set errno as needed.
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Overflow, underflow and divide-by-zero can occur for finite
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arguments and a domain error for Inf / Inf and 0 / 0. */
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#define CHECK_NARROW_DIV(RET, X, Y) \
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do \
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{ \
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if (!isfinite (RET)) \
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{ \
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if (isnan (RET)) \
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{ \
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if (!isnan (X) && !isnan (Y)) \
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__set_errno (EDOM); \
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} \
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else if (isfinite (X)) \
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__set_errno (ERANGE); \
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} \
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else if ((RET) == 0 && (X) != 0 && !isinf (Y)) \
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__set_errno (ERANGE); \
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} \
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while (0)
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/* Implement narrowing divide using round-to-odd. The arguments are
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X and Y, the return type is TYPE and UNION, MANTISSA and SUFFIX are
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as for ROUND_TO_ODD. */
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#define NARROW_DIV_ROUND_TO_ODD(X, Y, TYPE, UNION, SUFFIX, MANTISSA) \
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do \
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{ \
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TYPE ret; \
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\
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ret = (TYPE) ROUND_TO_ODD (math_opt_barrier (X) / (Y), \
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UNION, SUFFIX, MANTISSA); \
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\
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CHECK_NARROW_DIV (ret, (X), (Y)); \
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return ret; \
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} \
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while (0)
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/* Implement a narrowing divide function that is not actually
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narrowing or where no attempt is made to be correctly rounding (the
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latter only applies to IBM long double). The arguments are X and Y
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and the return type is TYPE. */
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#define NARROW_DIV_TRIVIAL(X, Y, TYPE) \
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do \
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{ \
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TYPE ret; \
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\
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ret = (TYPE) ((X) / (Y)); \
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CHECK_NARROW_DIV (ret, (X), (Y)); \
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return ret; \
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} \
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while (0)
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/* The following macros declare aliases for a narrowing function. The
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sole argument is the base name of a family of functions, such as
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"add". If any platform changes long double format after the
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introduction of narrowing functions, in a way requiring symbol
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versioning compatibility, additional variants of these macros will
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be needed. */
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#define libm_alias_float_double_main(func) \
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weak_alias (__f ## func, f ## func) \
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weak_alias (__f ## func, f32 ## func ## f64) \
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weak_alias (__f ## func, f32 ## func ## f32x)
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#ifdef NO_LONG_DOUBLE
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# define libm_alias_float_double(func) \
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libm_alias_float_double_main (func) \
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weak_alias (__f ## func, f ## func ## l)
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#else
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# define libm_alias_float_double(func) \
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libm_alias_float_double_main (func)
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#endif
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#define libm_alias_float32x_float64_main(func) \
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weak_alias (__f32x ## func ## f64, f32x ## func ## f64)
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#ifdef NO_LONG_DOUBLE
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# define libm_alias_float32x_float64(func) \
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libm_alias_float32x_float64_main (func) \
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weak_alias (__f32x ## func ## f64, d ## func ## l)
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#elif defined __LONG_DOUBLE_MATH_OPTIONAL
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# define libm_alias_float32x_float64(func) \
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libm_alias_float32x_float64_main (func) \
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weak_alias (__f32x ## func ## f64, __nldbl_d ## func ## l)
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#else
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# define libm_alias_float32x_float64(func) \
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libm_alias_float32x_float64_main (func)
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#endif
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#if __HAVE_FLOAT128 && !__HAVE_DISTINCT_FLOAT128
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# define libm_alias_float_ldouble_f128(func) \
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weak_alias (__f ## func ## l, f32 ## func ## f128)
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# define libm_alias_double_ldouble_f128(func) \
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weak_alias (__d ## func ## l, f32x ## func ## f128) \
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weak_alias (__d ## func ## l, f64 ## func ## f128)
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#else
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# define libm_alias_float_ldouble_f128(func)
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# define libm_alias_double_ldouble_f128(func)
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#endif
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#if __HAVE_FLOAT64X_LONG_DOUBLE
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# define libm_alias_float_ldouble_f64x(func) \
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weak_alias (__f ## func ## l, f32 ## func ## f64x)
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# define libm_alias_double_ldouble_f64x(func) \
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weak_alias (__d ## func ## l, f32x ## func ## f64x) \
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weak_alias (__d ## func ## l, f64 ## func ## f64x)
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#else
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# define libm_alias_float_ldouble_f64x(func)
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# define libm_alias_double_ldouble_f64x(func)
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#endif
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#define libm_alias_float_ldouble(func) \
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weak_alias (__f ## func ## l, f ## func ## l) \
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libm_alias_float_ldouble_f128 (func) \
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libm_alias_float_ldouble_f64x (func)
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#define libm_alias_double_ldouble(func) \
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weak_alias (__d ## func ## l, d ## func ## l) \
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libm_alias_double_ldouble_f128 (func) \
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libm_alias_double_ldouble_f64x (func)
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#define libm_alias_float64x_float128(func) \
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weak_alias (__f64x ## func ## f128, f64x ## func ## f128)
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#define libm_alias_float32_float128_main(func) \
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weak_alias (__f32 ## func ## f128, f32 ## func ## f128)
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#define libm_alias_float64_float128_main(func) \
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weak_alias (__f64 ## func ## f128, f64 ## func ## f128) \
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weak_alias (__f64 ## func ## f128, f32x ## func ## f128)
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#if __HAVE_FLOAT64X_LONG_DOUBLE
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# define libm_alias_float32_float128(func) \
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libm_alias_float32_float128_main (func)
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# define libm_alias_float64_float128(func) \
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libm_alias_float64_float128_main (func)
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#else
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# define libm_alias_float32_float128(func) \
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libm_alias_float32_float128_main (func) \
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weak_alias (__f32 ## func ## f128, f32 ## func ## f64x)
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# define libm_alias_float64_float128(func) \
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libm_alias_float64_float128_main (func) \
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weak_alias (__f64 ## func ## f128, f64 ## func ## f64x) \
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weak_alias (__f64 ## func ## f128, f32x ## func ## f64x)
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#endif
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#endif /* math-narrow.h. */
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