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2e2485ce05
This patch is using the corresponding GCC builtin for logbf, logb, logbl and logbf128 if the USE_FUNCTION_BUILTIN macros are defined to one in math-use-builtins-function.h. Co-Authored-By: Xi Ruoyao <xry111@xry111.site>
47 lines
1.2 KiB
C
47 lines
1.2 KiB
C
/* s_logbf.c -- float version of s_logb.c.
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*/
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/*
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* ====================================================
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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* Developed at SunPro, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* is preserved.
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* ====================================================
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*/
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#include <math.h>
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#include <math_private.h>
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#include <libm-alias-float.h>
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#include <fix-int-fp-convert-zero.h>
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#include <math-use-builtins.h>
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float
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__logbf (float x)
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{
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#if USE_LOGBF_BUILTIN
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return __builtin_logbf (x);
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#else
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int32_t ix, rix;
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GET_FLOAT_WORD (ix, x);
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ix &= 0x7fffffff; /* high |x| */
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if (ix == 0)
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return (float) -1.0 / fabsf (x);
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if (ix >= 0x7f800000)
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return x * x;
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if (__glibc_unlikely ((rix = ix >> 23) == 0))
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{
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/* POSIX specifies that denormal number is treated as
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though it were normalized. */
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rix -= __builtin_clz (ix) - 9;
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}
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if (FIX_INT_FP_CONVERT_ZERO && rix == 127)
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return 0.0f;
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return (float) (rix - 127);
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#endif /* ! USE_LOGBF_BUILTIN */
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}
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libm_alias_float (__logb, logb)
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