mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-14 17:11:06 +00:00
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.
|
|
*/
|
|
|
|
/*
|
|
* ====================================================
|
|
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
|
|
*
|
|
* Developed at SunPro, a Sun Microsystems, Inc. business.
|
|
* Permission to use, copy, modify, and distribute this
|
|
* software is freely granted, provided that this notice
|
|
* is preserved.
|
|
* ====================================================
|
|
*/
|
|
|
|
#include <math.h>
|
|
#include <math_private.h>
|
|
#include <libm-alias-float.h>
|
|
#include <fix-int-fp-convert-zero.h>
|
|
#include <math-use-builtins.h>
|
|
|
|
float
|
|
__logbf (float x)
|
|
{
|
|
#if USE_LOGBF_BUILTIN
|
|
return __builtin_logbf (x);
|
|
#else
|
|
int32_t ix, rix;
|
|
|
|
GET_FLOAT_WORD (ix, x);
|
|
ix &= 0x7fffffff; /* high |x| */
|
|
if (ix == 0)
|
|
return (float) -1.0 / fabsf (x);
|
|
if (ix >= 0x7f800000)
|
|
return x * x;
|
|
if (__glibc_unlikely ((rix = ix >> 23) == 0))
|
|
{
|
|
/* POSIX specifies that denormal number is treated as
|
|
though it were normalized. */
|
|
rix -= __builtin_clz (ix) - 9;
|
|
}
|
|
if (FIX_INT_FP_CONVERT_ZERO && rix == 127)
|
|
return 0.0f;
|
|
return (float) (rix - 127);
|
|
#endif /* ! USE_LOGBF_BUILTIN */
|
|
}
|
|
libm_alias_float (__logb, logb)
|