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unicorn/qemu/target/arm/vfp.decode

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target/arm: Add stubs for AArch32 VFP decodetree Add the infrastructure for building and invoking a decodetree decoder for the AArch32 VFP encodings. At the moment the new decoder covers nothing, so we always fall back to the existing hand-written decode. We need to have one decoder for the unconditional insns and one for the conditional insns, as otherwise the patterns for conditional insns would incorrectly match against the unconditional ones too. Since translate.c is over 14,000 lines long and we're going to be touching pretty much every line of the VFP code as part of the decodetree conversion, we create a new translate-vfp.inc.c to hold the code which deals with VFP in the new scheme. It should be possible to convert this into a standalone translation unit eventually, but the conversion process will be much simpler if we simply #include it midway through translate.c to start with. Backports commit 78e138bc1f672c145ef6ace74617db00eebaa2ba from qemu
2019-06-13 20:24:24 +00:00
# AArch32 VFP instruction descriptions (conditional insns)
#
# Copyright (c) 2019 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 the conditional VFP instructions are here:
# generally anything matching A32
# cccc 11.. .... .... .... 101. .... ....
# and T32
# 1110 110. .... .... .... 101. .... ....
# 1110 1110 .... .... .... 101. .... ....
# (but those patterns might also cover some Neon instructions,
# which do not live in this file.)
target/arm: Convert double-precision register moves to decodetree Convert the "double-precision" register moves to decodetree: this covers VMOV scalar-to-gpreg, VMOV gpreg-to-scalar and VDUP. Note that the conversion process has tightened up a few of the UNDEF encoding checks: we now correctly forbid: * VMOV-to-gpr with U:opc1:opc2 == 10x00 or x0x10 * VMOV-from-gpr with opc1:opc2 == 0x10 * VDUP with B:E == 11 * VDUP with Q == 1 and Vn<0> == 1 Signed-off-by: Peter Maydell <peter.maydell@linaro.org> --- The accesses of elements < 32 bits could be improved by doing direct ld/st of the right size rather than 32-bit read-and-shift or read-modify-write, but we leave this for later cleanup, since this series is generally trying to stick to fixing the decode. Backports commit 9851ed9269d214c0c6feba960dd14ff09e6c34b4 from qemu
2019-06-13 21:09:09 +00:00
# VFP registers have an odd encoding with a four-bit field
# and a one-bit field which are assembled in different orders
# depending on whether the register is double or single precision.
# Each individual instruction function must do the checks for
# "double register selected but CPU does not have double support"
# and "double register number has bit 4 set but CPU does not
# support D16-D31" (which should UNDEF).
%vm_dp 5:1 0:4
%vm_sp 0:4 5:1
%vn_dp 7:1 16:4
%vn_sp 16:4 7:1
%vd_dp 22:1 12:4
%vd_sp 12:4 22:1
%vmov_idx_b 21:1 5:2
%vmov_idx_h 21:1 6:1
# VMOV scalar to general-purpose register; note that this does
# include some Neon cases.
VMOV_to_gp ---- 1110 u:1 1. 1 .... rt:4 1011 ... 1 0000 \
vn=%vn_dp size=0 index=%vmov_idx_b
VMOV_to_gp ---- 1110 u:1 0. 1 .... rt:4 1011 ..1 1 0000 \
vn=%vn_dp size=1 index=%vmov_idx_h
VMOV_to_gp ---- 1110 0 0 index:1 1 .... rt:4 1011 .00 1 0000 \
vn=%vn_dp size=2 u=0
VMOV_from_gp ---- 1110 0 1. 0 .... rt:4 1011 ... 1 0000 \
vn=%vn_dp size=0 index=%vmov_idx_b
VMOV_from_gp ---- 1110 0 0. 0 .... rt:4 1011 ..1 1 0000 \
vn=%vn_dp size=1 index=%vmov_idx_h
VMOV_from_gp ---- 1110 0 0 index:1 0 .... rt:4 1011 .00 1 0000 \
vn=%vn_dp size=2
VDUP ---- 1110 1 b:1 q:1 0 .... rt:4 1011 . 0 e:1 1 0000 \
vn=%vn_dp
target/arm: Convert single-precision register moves to decodetree Convert the "single-precision" register moves to decodetree: * VMSR * VMRS * VMOV between general purpose register and single precision Note that the VMSR/VMRS conversions make our handling of the "should this UNDEF?" checks consistent between the two instructions: * VMSR to MVFR0, MVFR1, MVFR2 now UNDEF from EL0 (previously was a nop) * VMSR to FPSID now UNDEFs from EL0 or if VFPv3 or better (previously was a nop) * VMSR to FPINST and FPINST2 now UNDEF if VFPv3 or better (previously would write to the register, which had no guest-visible effect because we always UNDEF reads) We also tighten up the decode: we were previously underdecoding some SBZ or SBO bits. The conversion of VMOV_single includes the expansion out of the gen_mov_F0_vreg()/gen_vfp_mrs() and gen_mov_vreg_F0()/gen_vfp_msr() sequences into the simpler direct load/store of the TCG temp via neon_{load,store}_reg32(): we know in the new function that we're always single-precision, we don't need to use the old-and-deprecated cpu_F0* TCG globals, and we don't happen to have the declaration of gen_vfp_msr() and gen_vfp_mrs() at the point in the file where the new function is. Backports commit a9ab50011aeda2dd012da99069e078379315ea18 from qemu
2019-06-13 21:16:35 +00:00
VMSR_VMRS ---- 1110 111 l:1 reg:4 rt:4 1010 0001 0000
VMOV_single ---- 1110 000 l:1 .... rt:4 1010 . 001 0000 \
vn=%vn_sp
target/arm: Convert VFP two-register transfer insns to decodetree Convert the VFP two-register transfer instructions to decodetree (in the v8 Arm ARM these are the "Advanced SIMD and floating-point 64-bit move" encoding group). Again, we expand out the sequences involving gen_vfp_msr() and gen_msr_vfp(). Backports commit 81f681106eabe21c55118a5a41999fb7387fb714 from qemu
2019-06-13 21:19:58 +00:00
VMOV_64_sp ---- 1100 010 op:1 rt2:4 rt:4 1010 00.1 .... \
vm=%vm_sp
VMOV_64_dp ---- 1100 010 op:1 rt2:4 rt:4 1011 00.1 .... \
vm=%vm_dp
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