glibc/sysdeps/arm/e_sqrtf.c

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/* Compute square root for float. ARM version.
Copyright (C) 2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#ifdef __SOFTFP__
/* Use architecture-indendent sqrtf implementation. */
# include <sysdeps/ieee754/flt-32/e_sqrtf.c>
#else
/* Use VFP square root instruction. */
# include <math.h>
# include <sysdep.h>
float
__ieee754_sqrtf (float x)
{
float ret;
# if __ARM_ARCH >= 6
asm ("vsqrt.f32 %0, %1" : "=t" (ret) : "t" (x));
# else
/* As in GCC, for VFP9 Erratum 760019 avoid overwriting the
input. */
asm ("vsqrt.f32 %0, %1" : "=&t" (ret) : "t" (x));
# endif
return ret;
}
strong_alias (__ieee754_sqrtf, __sqrtf_finite)
#endif