unicorn/qemu/target/arm/m-nocp.decode
Peter Maydell 43d8441881 target/arm: Implement VSCCLRM insn
Implement the v8.1M VSCCLRM insn, which zeros floating point
registers if there is an active floating point context.
This requires support in write_neon_element32() for the MO_32
element size, so add it.

Because we want to use arm_gen_condlabel(), we need to move
the definition of that function up in translate.c so it is
before the #include of translate-vfp.c.inc.

Backports 83ff3d6add965c9752324de11eac5687121ea826
2021-03-03 17:57:30 -05:00

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# M-profile UserFault.NOCP exception handling
#
# 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 2.1 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
#
# For M-profile, the architecture specifies that NOCP UsageFaults
# should take precedence over UNDEF faults over the whole wide
# range of coprocessor-space encodings, with the exception of
# VLLDM and VLSTM. (Compare v8.1M IsCPInstruction() pseudocode and
# v8M Arm ARM rule R_QLGM.) This isn't mandatory for v8.0M but we choose
# to behave the same as v8.1M.
# This decode is handled before any others (and in particular before
# decoding FP instructions which are in the coprocessor space).
# If the coprocessor is not present or disabled then we will generate
# the NOCP exception; otherwise we let the insn through to the main decode.
%vd_dp 22:1 12:4
%vd_sp 12:4 22:1
&nocp cp
{
# Special cases which do not take an early NOCP: VLLDM and VLSTM
VLLDM_VLSTM 1110 1100 001 l:1 rn:4 0000 1010 0000 0000
# VSCCLRM (new in v8.1M) is similar:
VSCCLRM 1110 1100 1.01 1111 .... 1011 imm:7 0 vd=%vd_dp size=3
VSCCLRM 1110 1100 1.01 1111 .... 1010 imm:8 vd=%vd_sp size=2
NOCP 111- 1110 ---- ---- ---- cp:4 ---- ---- &nocp
NOCP 111- 110- ---- ---- ---- cp:4 ---- ---- &nocp
# From v8.1M onwards this range will also NOCP:
NOCP_8_1 111- 1111 ---- ---- ---- ---- ---- ---- &nocp cp=10
}