The alias for __m128i is typically something like:
typedef long long __m128i __attribute__((__vector_size__(16), __may_alias__));
and the part that ends up not getting preserved is the __may_alias__
attribute specifier.
So, in order to preserve that, we can just use a wrapper struct, so the
data type itself isn't being passed through the template.
Now that we've flipped the C++20 switch, let's start making use of
the nice new <bit> header.
I'm planning on handling this move away from BitUtils.h incrementally
in a series of PRs. There may be a few functions remaining in
BitUtils.h by the end that C++20 doesn't have any equivalents for.
This code was part of Dolphin's relicensing from v2 to v2+ a while back,
we just never updated these copyright headers. I double-checked that
segher gave us permission to relicense this code to v2+ on 2015-05-16.
SPDX standardizes how source code conveys its copyright and licensing
information. See https://spdx.github.io/spdx-spec/1-rationale/ . SPDX
tags are adopted in many large projects, including things like the Linux
kernel.
UNUSED is quite a generic macro name and has potential to clash with
other libraries, so rename it to DOLPHIN_UNUSED to prevent that, as well
as make its naming consistent with the force inline macro
Instead of globbing things under an ambiguous Common.h header, move
compiler-specifics over to Compiler.h. This gives us a dedicated home
for anything related to compilers that we want to make functional across
all compilers that we support.
This moves us a little closer to eliminating Common.h entirely.
This makes it easier to generate random numbers or fill a buffer with
random data in a cryptographically secure way.
This also replaces existing usages of RNG functions in the codebase:
* <random> is pretty hard to use correctly, and std::random_device does
not give enough guarantees about its results (it's
implementation-defined, non cryptographically secure and could be
deterministic on some platforms).
Doing things correctly is error prone and verbose.
* rand() is terrible and should not be used especially in crypto code.
- Move all of the ec functions into the Common::ec namespace.
- Give the public functions better names and some usage information.
- Move all of the "elt" related functions into an "elt" class including
all of the arithmetic operations, so that the logic becomes clearer
and feels less like assembly.
This also makes it much more obvious what the parameters are, instead
of only using unsigned char* (which doesn't tell anything about what
the pointer is used for or the size).
- Similarly, add a new "Point" class and move point functions there.
Overload the arithmetic operators to make calculations easier to read
The loops relied on unsigned integer overflow, which is not immediately
obvious. Replace them with less clever variants that are clearer.
Also implement bn_compare using std::memcmp.
This prevents the IOS crypto code and keys from being spread over
the codebase. Things only have to be implemented once, and can be
used everywhere from the IOS code.
Additionally, since ES exposes some IOSC calls directly (DeleteObject
and Encrypt/Decrypt), we need this for proper emulation.
Currently, this only supports AES key objects.
