The documentation is incorrect about this instruction. It claims that
you use 66h prefix to choose between operating at 8B or 16B.
This is incorrect, real hardware only responds to REX.W for choosing the
operating size. These other prefixes are ignored but is still accepted as
an instruction decoding.
This matches the AArch64 implementation fairly well.
Bundles RDRAND and RDSEED together for simplification, both instructions
are a single flag on AArch64.
This region is reserved for hypervisor uses. Let's follow other examples
and return a hypervisor vendor id signature as another way for software
to find if it is running under FEX-Emu.
In some cases we can generate more optimal code if we have more
information about a syscall which number gets const-propagated.
In particular optimizing through syscalls, not synchronizing state, and
never returning.
- Noreturn is used by a syscall that never returns, like exit.
This means that it never needs to try and synchronize state coming back
- Not synchronizing state and optimizing through syscalls
Useful for syscalls that don't read the state past arguments and only
returns a value.
This picks up all the instruction implementations, including 3DNow!
Extended and the Geode specific instructions that were added.
Most of these match preexisting SSE instructions except that they
operate at 64-bit and in the MMX registers.
We already decoded the modrm `rm` bits, check while decoding modrm to
ensure we don't try decoding it again.
Was causing double decoding of SIB and displacement bytes, breaking
things
This allows x87 fallbacks to be loaded from the upcoming code cache
without relocations.
Only 40 pointers necessary to store and means x87 code won't hit
relocations heavily.
Probably improves performance slightly on the x86 host side but should
be neglible.
Needs #1574 and #1575 merged first.
Just like the previous AArch64 JIT.
These pointers are process or thread specific depending on the pointer
and should be loaded from the State object.
Performance here might slightly increase.
This is required for code cache on x86
Needs #1574 merged first.
These pointers are process or thread specific depending on which pointer
it is.
All of these pointers end up getting used inside of the JIT blocks
themselves and with code caching would result in a ton of relocations
occuring inside the code.
The pointers used within the dispatcher don't currently matter since I'm
not expecting to cache the dispatcher itself. It's only a page per
thread after all. This does move us significantly closer towards using a
single dispatcher for all threads though.
The performance impact of this change is unlikely to be felt at all,
some locations have less code generation which could improve perf
slightly. Some locations move from a 1-3 cycle constant calculation to a
4 cycle load, hard to be felt since it gets hidden by other
instructions.
x86-64 JIT will be added soon after this
This is pulled from the code cache PR. Will be necessary for supporting
relocations.
Not currently being used but will be once we have code caching in place.
Just noticed this while casually reading the x86 architecture manuals.
The move segment registers instructions ignore the REX.R prefix on the
segment register.
Previously this was expected to create an invalid register selection.
A little bit silly but sure, support it.
This table is particularly terrible. CRC32 is the first instruction in
this table that needs either prefix `72h` OR `66h && F2h`
For 8bit CRC32, this ignores the 66h operand size override prefix.
- But our table decoding didn't handle this
For 16bit/32bit/64bit CRC32 this behaviour changes depending on 66h
prefix AND REX.W
- 66h prefix is ignored when REX.W is set, always 64bit but it falls
down the other table path
This is an absolutely weird edge case that nobody should hit, but here
we are.
This was mainly an optimization around memory usage. ALU ops tend to
bloat the IR quite heavily, but I also noticed a 2-4% uplift in
performance of some applications. So a nice side effect.
Should let us more aggressively target reducing our IR intrusive
allocator size since this is quite reduced.
In a pedantic heavy ALU op code block this reduces the number of IR ops
from 14,756 IR ops to 2,016 prior to optimization.
After optimization both had reduced down to 50 IR ops, proving the
output IR was the same.
By default we won't build with the interpeter to reduce user confusion.
The interpreter isn't really useful to end users so remove it.
Completely removes it from building except for the fallback operations.
This also removes the selection from FEXConfig to remove selection
confusion there.
File Stats:
FEXLoader Size with Interpreter: 3422768 bytes
FEXLoader Size without Interpreter: 3301944 bytes
Size difference: 96.4699915%
Bytes removed: 120824 bytes
4k pages removed: 29.498046875 -> 30 rounded up
VM Stats (Reported from bloaty):
Memory Size with Interpreter: 6.50Mi
Memory Size without Interpreter: 6.38Mi
Size difference: 98.1538462%
Currently force disabled until the rest of SSE 4.2 is enabled
This is to remind us in the future that SSE4.2 can only be enabled in
CPUID with CRC32 instruction support.
This cropped up mostly with multiblock and `jmp <signed displacement>`
This also happened with non multiblock `jcc <signed displacement>`
Due to how IR relocations occur, this needs to happen fairly late but
isn't a big deal.
Fixes#1517
Needs to be a string_view for the MIDR for the StrConv helper to work in
this instance.
There is no null terminator character when reading from the file is why.
Ryan Houdek