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When we want to inline builtin math functions, like truncf, for
extern float truncf (float __x) __attribute__ ((__nothrow__ )) __attribute__ ((__const__));
extern float __truncf (float __x) __attribute__ ((__nothrow__ )) __attribute__ ((__const__));
float (truncf) (float) asm ("__truncf");
compiler may redirect truncf calls to __truncf, instead of inlining it
(for instance, clang). The USE_TRUNCF_BUILTIN is 1 to indicate that
truncf should be inlined. In this case, we don't want the truncf
redirection:
1. For each math function which may be inlined, we define
#if USE_TRUNCF_BUILTIN
# define NO_truncf_BUILTIN inline_truncf
#else
# define NO_truncf_BUILTIN truncf
#endif
in <math-use-builtins.h>.
2. Include <math-use-builtins.h> in include/math.h.
3. Change MATH_REDIRECT to
#define MATH_REDIRECT(FUNC, PREFIX, ARGS) \
float (NO_ ## FUNC ## f ## _BUILTIN) (ARGS (float)) \
asm (PREFIX #FUNC "f");
With this change If USE_TRUNCF_BUILTIN is 0, we get
float (truncf) (float) asm ("__truncf");
truncf will be redirected to __truncf.
And for USE_TRUNCF_BUILTIN 1, we get:
float (inline_truncf) (float) asm ("__truncf");
In both cases either truncf will be inlined or the internal alias
(__truncf) will be called.
It is not required for all math-use-builtin symbol, only the one
defined in math.h. It also allows to remove all the math-use-builtin
inclusion, since it is now implicitly included by math.h.
For MIPS, some math-use-builtin headers include sysdep.h and this
in turn includes a lot of extra headers that do not allow ldbl-128
code to override alias definition (math.h will include
some stdlib.h definition). The math-use-builtin only requires
the __mips_isa_rev, so move the defintion to sgidefs.h.
Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Co-authored-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
69 lines
1.7 KiB
C
69 lines
1.7 KiB
C
/* Extract signed integral and fractional values.
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Copyright (C) 1993-2025 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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<https://www.gnu.org/licenses/>. */
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#include <math.h>
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#include <libm-alias-float.h>
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#include "math_config.h"
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float
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__modff (float x, float *iptr)
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{
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uint32_t t = asuint (x);
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#if USE_TRUNCF_BUILTIN
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if (is_inf (t))
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{
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*iptr = x;
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return copysignf (0.0, x);
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}
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*iptr = truncf (x);
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return copysignf (x - *iptr, x);
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#else
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int e = get_exponent (t);
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/* No fraction part. */
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if (e < MANTISSA_WIDTH)
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{
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if (e < 0)
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{
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/* |x|<1 -> *iptr = +-0 */
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*iptr = asfloat (t & SIGN_MASK);
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return x;
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}
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uint32_t i = MANTISSA_MASK >> e;
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if ((t & i) == 0)
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{
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/* x in integral, return +-0 */
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*iptr = x;
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return asfloat (t & SIGN_MASK);
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}
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*iptr = asfloat (t & ~i);
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return x - *iptr;
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}
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/* Set invalid operation for sNaN. */
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*iptr = x * 1.0f;
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if ((e == 0x80) && (t & MANTISSA_MASK))
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return *iptr;
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return asfloat (t & SIGN_MASK);
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#endif
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}
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#ifndef __modff
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libm_alias_float (__modf, modf)
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#endif
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