What are the codes that contain the marcos that are created directly or the .word directives that are used in their work to make certain things work that cannot work otherwise?

[françai s]

It has come to my attention the following:

"The minority of  FreeBSD developers either create a macro expands to
something like ".word <foo> “ or sometimes the .word <foo> is just hard
coded inline when there’s only going to be one of them, sometimes expose
them both in assembly and in C code, in which case what we do varies a bit
to accommodate the different language’s syntax. It is rare, but has
happened, that we only expose it to C code.

Generally, though, the minority of  FreeBSD developers  try to add support
for the opcodes to gas so that get the constraint testing it does (making
sure the opcode is supported at the level you are compiling, making sure it
isn’t in a delay slot or violating some other precondition for its use).

People generally don’t write in raw machine opcodes. That is independent of
FreeBSD.

However, a few, specialized people will find the need to do it from time to
time. Usually because they are porting FreeBSD to a newer processor that
needs newer opcodes to do context switching, optimize interrupt handling,
code with a new type of cache coherency, etc. These people look up the
assembler in the docs from the vendor and then create the .word workaround
to make sure things work. If they have the time, they may add it to our
somewhat ancient gas assembler as well."

What are the codes that contain  the marcos that I described above
sometimes when doing specific, low-level coding?

What are the codes that contain the marcos that are created directly or the
.word directives that are used in their work to make certain things work
that cannot work otherwise?