qemu-e2k/target/arm/neon-shared.decode
Peter Maydell 625e3dd44a target/arm: Add stubs for AArch32 Neon decodetree
Add the infrastructure for building and invoking a decodetree decoder
for the AArch32 Neon encodings.  At the moment the new decoder covers
nothing, so we always fall back to the existing hand-written decode.

We follow the same pattern we did for the VFP decodetree conversion
(commit 78e138bc1f and following): code that deals
with Neon will be moving gradually out to translate-neon.vfp.inc,
which we #include into translate.c.

In order to share the decode files between A32 and T32, we
split Neon into 3 parts:
 * data-processing
 * load-store
 * 'shared' encodings

The first two groups of instructions have similar but not identical
A32 and T32 encodings, so we need to manually transform the T32
encoding into the A32 one before calling the decoder; the third group
covers the Neon instructions which are identical in A32 and T32.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200430181003.21682-4-peter.maydell@linaro.org
2020-05-04 12:57:56 +01:00

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# AArch32 Neon instruction descriptions
#
# Copyright (c) 2020 Linaro, Ltd
#
# This 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 of the License, or (at your option) any later version.
#
# This 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 this library; if not, see <http://www.gnu.org/licenses/>.
#
# This file is processed by scripts/decodetree.py
#
# Encodings for Neon instructions whose encoding is the same for
# both A32 and T32.
# More specifically, this covers:
# 2reg scalar ext: 0b1111_1110_xxxx_xxxx_xxxx_1x0x_xxxx_xxxx
# 3same ext: 0b1111_110x_xxxx_xxxx_xxxx_1x0x_xxxx_xxxx