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While DI <-> BF conversions can be handled (and are) through
DI <-> XF <-> BF and for narrower integral modes even sometimes
through DF or SF, because XFmode has 64-bit mantissa and so all
the DImode values are exactly representable in XFmode.
That is not the case for TImode, and while e.g. the HF -> TI
conversions are IMHO useless in libgcc, because HFmode has
-65504.0f16, 65504.0f16 range, all the integers will be already
representable in SImode (or even HImode for unsigned) and so
I think HF -> DI -> TI conversions are faster and valid,
BFmode has roughly the same range as SFmode and so we absolutely need
the TI -> BF conversions to avoid double rounding.
As for BF -> TI conversions, they can be either also implemented
in libgcc, or they can be implemented (as done in this commit)
as BF -> SF -> TI conversions with the same code generation used
elsewhere, just doing the 16-bit left shift of the bits - I think
we don't need to handle sNaNs during the BF -> SF part because
SF -> TI (which is already a libcall too) will handle that too.
The BF -> SF -> TI path avoids wasting
32: 0000000000015e10 321 FUNC GLOBAL DEFAULT 13 __fixbfti@@GCC_13.0.0
89: 0000000000015f60 299 FUNC GLOBAL DEFAULT 13 __fixunsbfti@@GCC_13.0.0
2023-03-10 Jakub Jelinek <jakub@redhat.com>
PR target/107703
* optabs.cc (expand_fix): For conversions from BFmode to integral,
use shifts to convert it to SFmode first and then convert SFmode
to integral.
* soft-fp/floattibf.c: New file.
* soft-fp/floatuntibf.c: New file.
* config/i386/libgcc-glibc.ver: Export __float{,un}tibf @ GCC_13.0.0.
* config/i386/64/t-softfp (softfp_extras): Add floattibf and
floatuntibf.
(CFLAGS-floattibf.c, CFLAGS-floatunstibf.c): Add -msse2.
46 lines
1.6 KiB
C
46 lines
1.6 KiB
C
/* Software floating-point emulation.
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Convert a 128bit unsigned integer to bfloat16
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Copyright (C) 2007-2023 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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In addition to the permissions in the GNU Lesser General Public
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License, the Free Software Foundation gives you unlimited
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permission to link the compiled version of this file into
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combinations with other programs, and to distribute those
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combinations without any restriction coming from the use of this
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file. (The Lesser General Public License restrictions do apply in
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other respects; for example, they cover modification of the file,
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and distribution when not linked into a combine executable.)
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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 "soft-fp.h"
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#include "brain.h"
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BFtype
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__floatuntibf (UTItype i)
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{
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FP_DECL_EX;
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FP_DECL_B (A);
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BFtype a;
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FP_INIT_ROUNDMODE;
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FP_FROM_INT_B (A, i, TI_BITS, UTItype);
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FP_PACK_RAW_B (a, A);
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FP_HANDLE_EXCEPTIONS;
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return a;
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}
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