On Fri, 6 Apr 2001, Kevin D. Kissell wrote: > What advantage would there be to using sysmips() as opposed > to doing the ll/sc emulation? It seems to me that the decode path > in the kernel would be just as fast, and there would be a single > "ABI" for all programs - the ll/sc instructions themselves. It was discussed a few times already. It's ugly and is an overkill for UP machines -- you take at least two faults for ll/sc emulation and only a single syscall for TAS. Sysmips() is ugly as well but it's a legacy call -- I proposed implementing _test_and_set() call which would be the underlying implementation of the ABI _test_and_set() library call for MIPS I systems (which should probably be the only atomic operation available to the userland). Unfortunately the lack of time prevents me from doing it. At least _test_and_set() has well-defined semantics. It looks straightforward as well. -- + Maciej W. Rozycki, Technical University of Gdansk, Poland + +--------------------------------------------------------------+ + e-mail: macro@ds2.pg.gda.pl, PGP key available +
