arch-arm, cpu: fix ARM ubsan build on GCC 7.4.0

In src/cpu/reg_class.hh, numPinnedWrites was unset because the
constructors were not well factored out.

Change-Id: Ib2fc8d34a1adf5c48826d257a31dd24dfa64a08a
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/20048
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

arch-arm: implement VMINNM scalar thumb

VMINNM was implemented at Iabbbca2932557cf6c98ce36690c385c3ddf39ed8 but
the thumb scalar encoding was missing. This patch implements it.

Change-Id: Ia29ec77dbd82f6be6b3d040a0e737794f52c33bf
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/19108
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

arch-arm: implement VMINNM and VMAXNM scalar version

ARMv8.2 16-bit versions have not yet been implemented, but a placeholders
were created for them.

Refactor the nearby decoding tree to closely match the ARM spec A32 decode
table.

That piece of the tree can also be called from thumb which decodes it in
the same way, although the thumb decode table has a different terminology

The old code didn't match neither A32 or T32 terminologies, so it is
better to at least match one of them to help verify correctness.

Change-Id: Iabbbca2932557cf6c98ce36690c385c3ddf39ed8
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18690
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

arch-arm: implement VMINNM and VMAXNM SIMD version

This instruction is backported from aarch64.

In order to use the existing fplibMinNum backend, we first move
VMIN and VPMIN to use fplib. Adding VMINNM is then trivial.

Change-Id: I404daabeb6079f60e51a648a06d5b3e54f1c24a9
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18689
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

arch-arm: rename operands to match spec in isa/formats/fp.isa

Matches ARM DDI 0487D.a decoding tables.

Change-Id: I48338ef956a04308d55d1022229ebe0962a8fe5d
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18688
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

arch-arm: Fixing implicit fallthrough build errors

2c242d6 introduced implicit-fallthrough errors when building against
ARM.

Added "default: return new Unknown(machInst);" to offending switch
statements; please verify this is the corret behavior

Signed-off-by: Ryan Gambord

Change-Id: I5f5e3661ec562d4a3b2699e07d1195e6877ff959
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/17071
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>

arch-arm: implement floating point aarch32 VCVTA family

These instructions round floating point to integer, and were added to
aarch32 as an extension to ARMv7.

Change-Id: I62d1705badc95a4e8954a5ad62b2b6bc9e4ffe00
Reviewed-on: https://gem5-review.googlesource.com/c/16788
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

arch-arm: AArch32 Crypto AES

This patch implements the AArch32 AES instructions
from the Crypto extension.

Change-Id: I51e6deda748b0c26135bcfe9d0c7128f3af91f3d
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Matt Horsnell <matt.horsnell@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/13248
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

arch-arm: AArch32 Crypto SHA

This patch implements the AArch32 secure hashing instructions
from the Crypto extension.

Change-Id: Iaba8424ab71800228a9aff039d93f5c35ee7d8e5
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/13247
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

arch-arm: Add FP16 support introduced by Armv8.2-A

This changeset adds support for FP/SIMD instructions with
half-precision floating-point operands.

Change-Id: I4957f111c9c5e5d6a3747fe9d169d394d642fee8
Signed-off-by: Giacomo Gabrielli <giacomo.gabrielli@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/13084
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

arm: Fix implicit-fallthrough warnings when building with gcc-7+

gcc 7 onwards have additional heuristics to detect implicit
fallthroughs and it fails the build with warnings for ARM as a result.
There was one gcc bug[1] that I fixed but the rest are cases that gcc
cannot detect due to the point at which it does the fallthrough check.
Most of this patch adds __builtin_unreachable() hints in places that throw
this warning to indicate to gcc that the fallthrough will never
happen.

The remaining cases are actually possible fallthroughs due to
incorrect code running on the simulator; in which case an Unknown
instruction is returned.

[1] https://gcc.gnu.org/ml/gcc-patches/2018-02/msg01105.html

Change-Id: I1baa9fa0ed15181c10c755c0bd777f88b607c158
Signed-off-by: Siddhesh Poyarekar <siddhesh.poyarekar@gmail.com>
Reviewed-on: https://gem5-review.googlesource.com/8541
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>

isa,arm: Add missing AArch32 FP instructions

This commit adds missing non-predicated, scalar floating point
instructions. Specifically VRINT* floating point integer rounding
instructions and VSEL* floating point conditional selects.

Change-Id: I23cbd1389f151389ac8beb28a7d18d5f93d000e7
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Nathanael Premillieu <nathanael.premillieu@arm.com>

arm: Add support for ARMv8 (AArch64 & AArch32)

Note: AArch64 and AArch32 interworking is not supported. If you use an AArch64
kernel you are restricted to AArch64 user-mode binaries. This will be addressed
in a later patch.

Note: Virtualization is only supported in AArch32 mode. This will also be fixed
in a later patch.

Contributors:
Giacomo Gabrielli (TrustZone, LPAE, system-level AArch64, AArch64 NEON, validation)
Thomas Grocutt (AArch32 Virtualization, AArch64 FP, validation)
Mbou Eyole (AArch64 NEON, validation)
Ali Saidi (AArch64 Linux support, code integration, validation)
Edmund Grimley-Evans (AArch64 FP)
William Wang (AArch64 Linux support)
Rene De Jong (AArch64 Linux support, performance opt.)
Matt Horsnell (AArch64 MP, validation)
Matt Evans (device models, code integration, validation)
Chris Adeniyi-Jones (AArch64 syscall-emulation)
Prakash Ramrakhyani (validation)
Dam Sunwoo (validation)
Chander Sudanthi (validation)
Stephan Diestelhorst (validation)
Andreas Hansson (code integration, performance opt.)
Eric Van Hensbergen (performance opt.)
Gabe Black

scons: Fix up numerous warnings about name shadowing

This patch address the most important name shadowing warnings (as
produced when using gcc/clang with -Wshadow). There are many
locations where constructor parameters and function parameters shadow
local variables, but these are left unchanged.

GCC: Get everything working with gcc 4.6.1.

And by "everything" I mean all the quick regressions.

ARM: Further break up condition code into NZ, C, V bits.

Break up the condition code bits into NZ, C, V registers. These are individually
written and this removes some incorrect dependencies between instructions.

ARM: Break up condition codes into normal flags, saturation, and simd.

This change splits out the condcodes from being one monolithic register
into three blocks that are updated independently. This allows CPUs
to not have to do RMW operations on the flags registers for instructions
that don't write all flags.

ARM: Fix small bug with vcvt instruction

ARM: Fix small bug with VLDM/VSTM instructions.

ARM: The ARM decoder should not panic when decoding undefined holes is arch.

This can abort simulations when the fetch unit runs ahead and speculatively
decodes instructions that are off the execution path.

ARM: Seperate out the renamable bits in the FPSCR.

ARM: Implement all ARM SIMD instructions.

ARM: Decode neon memory instructions.

ARM: Decode the neon instruction space.

ARM: Detect a bad offset field for the VFP Ldm/Stm instructions in the decoder.

ARM: Get rid of some of the old FP implementation.

ARM: Implement conversion to/from half precision.

ARM: Even though writes to MVFR0/1 should be unpredictable, we need to make them to do nothing.

ARM: Implement the version of VMRS that writes to the APSR.

ARM: Implement the VCMPE instruction.

ARM: Implement the version of VCVT float to int that rounds towards zero.

ARM: Implement the floating/fixed point VCVT instructions.

ARM: Implement the VFP version of VCMP.

ARM: Add support for VFP vector mode.

ARM: Implement VCVT between double and single width FP.

ARM: Implement vcvt between int and fp. Ignore rounding.

ARM: Consolidate the VFP register index computation code.

ARM: Implement the VFP negated multiplies.

ARM: Implement the VFP versions of VMLA and VMLS.

ARM: Implement the VFP version of vdiv and vsqrt.

ARM: Implement the VFP version of vsub.

ARM: Implement the VFP version of vadd.

ARM: Implement the VFP version of vabs.

ARM: Implement the VFP version of vneg.

ARM: Implement the VFP version of vmul.

ARM: Move the VFP data operation decode into a function.

ARM: Move the FP decode blocks into functions.

ARM: Decode the VSTR instruction.

ARM: Decode the VLDR instruction.

ARM: Decode all the various forms of vmov.

ARM: Decode the VMRS instruction.

ARM: Decode the VMSR instruction.

ARM: Decode 8, 16, and 32 bit transfers between core and extension (fp) registers.

ARM: Decode the VFP load/store multiple instructions.

ARM: Split the condition codes out of the CPSR.

This allows those bits to be renamed while allowing the other fields to
control the behavior of the processor.

ARM: Remove the currently unecessary FPAOp class.

ARM: Make the isa parser aware that CPSR is being used.

ARM: Pull some static code out of the isa desc and create miscregs.hh.

arm: add ARM support to M5