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author | Jakub Jelinek <jakub@redhat.com> | 2024-02-01 16:58:49 +0100 |
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committer | Jakub Jelinek <jakub@redhat.com> | 2024-02-01 19:06:54 +0100 |
commit | 275607a07fb2a60757ba47ec3f1f4e645ad19bb1 (patch) | |
tree | f9fe8b8ea1910347493fd2ca2b3b410ffb9dfea1 /soft-fp/truncbfhf2.c | |
parent | 83d8d289b295406e30bc8a079286b093d552c3a5 (diff) | |
download | glibc-275607a07fb2a60757ba47ec3f1f4e645ad19bb1.tar.gz glibc-275607a07fb2a60757ba47ec3f1f4e645ad19bb1.tar.xz glibc-275607a07fb2a60757ba47ec3f1f4e645ad19bb1.zip |
soft-fp: Add brain format support
In https://gcc.gnu.org/r13-3292 I've added brain format support (std::bfloat16_t) on the GCC side, but as glibc has the master copy of soft-fp, the following patch adds the files from that commit and from https://gcc.gnu.org/r13-6598 and https://gcc.gnu.org/r13-6622 The files are not used by glibc right now.
Diffstat (limited to 'soft-fp/truncbfhf2.c')
-rw-r--r-- | soft-fp/truncbfhf2.c | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/soft-fp/truncbfhf2.c b/soft-fp/truncbfhf2.c new file mode 100644 index 0000000000..627f8c6559 --- /dev/null +++ b/soft-fp/truncbfhf2.c @@ -0,0 +1,75 @@ +/* Software floating-point emulation. + Truncate bfloat16 into IEEE half. + Copyright (C) 2022-2024 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 "brain.h" +#include "single.h" + +/* BFtype and HFtype are unordered, neither is a superset or subset + of each other. Convert BFtype to SFtype (lossless) and then + truncate to HFtype. */ + +HFtype +__truncbfhf2 (BFtype a) +{ + FP_DECL_EX; + FP_DECL_H (A); + FP_DECL_S (B); + FP_DECL_B (R); + SFtype b; + HFtype r; + + FP_INIT_ROUNDMODE; + /* Optimize BFtype to SFtype conversion to simple left shift + by 16 if possible, we don't need to raise exceptions on sNaN + here as the SFtype to HFtype truncation should do that too. */ + if (sizeof (BFtype) == 2 + && sizeof (unsigned short) == 2 + && sizeof (SFtype) == 4 + && sizeof (unsigned int) == 4) + { + union { BFtype a; unsigned short b; } u1; + union { SFtype a; unsigned int b; } u2; + u1.a = a; + u2.b = (u1.b << 8) << 8; + b = u2.a; + } + else + { + FP_UNPACK_RAW_B (A, a); + FP_EXTEND (S, B, 1, 1, B, A); + FP_PACK_RAW_S (b, B); + } + FP_UNPACK_SEMIRAW_S (B, b); + FP_TRUNC (H, S, 1, 1, R, B); + FP_PACK_SEMIRAW_H (r, R); + FP_HANDLE_EXCEPTIONS; + + return r; +} |