glibc/soft-fp/truncdfhf2.c
liuhongt 6ec6c77867 soft-fp: Add __extendhfsf2/__extendhfdf2, __truncsfhf2/__truncdfhf2, __eqhf2/__nehf2
1. Add __extendhfdf2/__extendhfsf2 to return an IEEE half converted to IEEE double/single.
2. Add __truncdfhf2/__extendsfhf2 to truncate IEEE double/single into IEEE half.
3. Add __eqhf2/__nehf2 to return 0 if a == b and a,b are not NAN, otherwise return 1.

These are needed by x86 _Float16:

https://software.intel.com/content/www/us/en/develop/download/intel-avx512-fp16-architecture-specification.html

support in GCC.
2021-07-07 08:01:32 -07:00

53 lines
1.7 KiB
C

/* Software floating-point emulation.
Truncate IEEE double into IEEE half.
Copyright (C) 2021 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.
In addition to the permissions in the GNU Lesser General Public
License, the Free Software Foundation gives you unlimited
permission to link the compiled version of this file into
combinations with other programs, and to distribute those
combinations without any restriction coming from the use of this
file. (The Lesser General Public License restrictions do apply in
other respects; for example, they cover modification of the file,
and distribution when not linked into a combine executable.)
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/>. */
#include "soft-fp.h"
#include "half.h"
#include "double.h"
HFtype
__truncdfhf2 (DFtype a)
{
FP_DECL_EX;
FP_DECL_D (A);
FP_DECL_H (R);
HFtype r;
FP_INIT_ROUNDMODE;
FP_UNPACK_SEMIRAW_D (A, a);
#if _FP_W_TYPE_SIZE < _FP_FRACBITS_D
FP_TRUNC (H, D, 1, 2, R, A);
#else
FP_TRUNC (H, D, 1, 1, R, A);
#endif
FP_PACK_SEMIRAW_H (r, R);
FP_HANDLE_EXCEPTIONS;
return r;
}