Serenity has explicit_bzero() in LibC with the same implementation,
however we need to be able to use this from Lagom on all platforms
that we support building serenity on. I've implemented it in AK for
this reason.
For non-x86 targets, it's not very nice to define inline functions in
AK/Memory.h with asm volatile implementations. Guard this inline
assembly with ARCH(I386) and provide portable alternatives. Since we
always compile with optimizations, the hand-vectorized memset and
memcpy seem to be of dubious value, but we'll keep them here until
proven one way or another.
This should fix the Lagom build on native M1 macOS that was reported
on Discord the other day.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
There's no great advantage to using MMX instructions here on modern
processors, since REP MOVSB/STOSB are optimized in microcode anyway
and tend to run much faster than MMX/SSE/AVX variants.
This also makes it much easier to implement high-level emulation of
memcpy/memset in UserspaceEmulator once we get there. :^)
This was supposed to be the foundation for some kind of pre-kernel
environment, but nobody is working on it right now, so let's move
everything back into the kernel and remove all the confusion.
Move the "fast memcpy" stuff out of StdLibExtras.h and into Memory.h.
This will break a ton of things that were relying on StdLibExtras.h
to include a bunch of other headers. Fix will follow immediately after.
This makes it possible to include StdLibExtras.h from Types.h, which is
the main point of this exercise.
