Date: Sun, 9 Oct 2016 11:06:38 -0300 From: =?UTF-8?Q?fran=C3=A7ai_s?= <romapera15@gmail.com> To: freebsd-drivers@freebsd.org Subject: What are the codes that contain the marcos that are created directly or the .word directives? Message-ID: <CAK_6RwfED1tMBLLaArBjS7Uq2PHk3YAsa3YH%2BmPS37=c%2ByKaVQ@mail.gmail.com>
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It has come to my attention the following: "The minority of FreeBSD developers either create a macro expands to something like ".word <foo> =E2=80=9C or sometimes the .word <foo> is just = hard coded inline when there=E2=80=99s only going to be one of them, sometimes e= xpose them both in assembly and in C code, in which case what we do varies a bit to accommodate the different language=E2=80=99s 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=E2=80=99t in a delay slot or violating some other precondition for its = use). People generally don=E2=80=99t write in raw machine opcodes. That is indepe= ndent 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." A few, specialized people still will find the need of write in raw machine opcodes from time to time because usually 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 still look up the assembler in the docs from the vendor and then create the .word workaround to make sure things work? If they still have the time, they still may add it to our somewhat ancient gas assembler as well? Some developers of FreeBSD still use the marcos that I described above sometimes when doing specific, low-level coding? A handful of developers of FreeBSD still create the marcos directly or use the .word directives in their work to make certain things work that cannot work otherwise? If yes, 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? If is not possible speak what are all this codes, please, quote good amount of examples.
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