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5c2b21c478
The generic implementation is slight more optimized than the powerpc one, where it has a more optimized inf/nan check (by not using FP unit checks, along with branch prediction hints), and removed one branch by issuing trunc instead of a combination of floor/ceil (which also generated less code). On power10 with gcc 14.2.1: reciprocal-throughput master patch difference workload-0_1 1.5210 1.3942 8.34% workload-1_maxint 2.0926 1.3940 33.38% workload-maxint_maxfloat 1.7851 1.3940 21.91% workload-integral 1.5216 1.3941 8.37% latency master patch difference workload-0_1 1.5928 2.6337 -65.35% workload-1_maxint 3.2929 2.6337 20.02% workload-maxint_maxfloat 1.9697 2.6341 -33.73% workload-integral 2.0597 2.6337 -27.87% Checked on powerpc64le-linux-gnu. Reviewed-by: Sachin Monga <smonga@linux.ibm.com>
70 lines
1.8 KiB
C
70 lines
1.8 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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#include <math-use-builtins-trunc.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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