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Re: lock

From: Jeff Johnston <jjohnstn at redhat dot com>
To: Rosière mathieu <mathieu dot rosiere at lip6 dot fr>
Cc: newlib at sources dot redhat dot com
Date: Tue, 04 Jul 2006 13:22:40 -0400
Subject: Re: lock
References: <1151603749.7274.9.camel@mc-algeroth>

Rosière mathieu wrote:

Hi,

I have a system with multi cpu. All thread running on each cpu, and
write a message on a tty. But the primitive of lock (in <sys/lock.h>) is
not implemented. (in configure.host, i have set the flag
newlib_multithread)

* Have an implementation of this primitive?

You will have to provide your own. There is code for the x86-linux lock in the libc/sys/linux/machine/i386 directory. Are we talking about an existing newlib platform or something new?

* Are they hardware's dependant? (by exemple to use a primitive test and
set)

Yes, it is hardware dependent. If you have an atomic test and set insn or something similar, it is reasonably straightforward. If there is no hardware support you will have to resort to some form of spin-lock.

-- Jeff J.

References:
- lock
  - From: Rosière mathieu

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