Date: Thu, 2 Apr 2009 09:06:05 +0200 From: Luigi Rizzo <rizzo@iet.unipi.it> To: current@freebsd.org Subject: cmpxchg / atomic_cmpset_int emulation for userland (i386) ? Message-ID: <20090402070605.GA96848@onelab2.iet.unipi.it>
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Hi, I have some list manipulation algorithm that I would like to use that relies rather centrally on atomic_cmpset_int(). This is an atomic instruction on 486+, but not available on 386 and maybe other platforms. i386/atomic.h has a replacement but it uses "pushfl; cli; ... popfl;" so it cannot run in userland. I was wondering if there is a good emulation for that instruction on the i386 that is suitable for userland (other architectures we support have a CPU instruction that does it, or in the case of ARM, a usable emulation for userland). cheers luigi
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