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Re: Why is __cpu_simple_lock_t an unsigned char?

On Nov 6, 2008, at 12:35 AM, Heikki Krogerus wrote:

Matt Thomas wrote:

On Nov 5, 2008, at 11:21 PM, Heikki Krogerus wrote:

This probably is a silly quistion, I know, but how should the
ldrex/strex be
handled in the future? Our ARM1136JF-S does not seem to support

Thumb does not support the swp instruction.

because armv4 and later have swpb (swap byte).

but the ARM architecture reference manual mentions that "From ARMv6, use of SWP
and SWPB instructions is deprecated" and from the comments in
sys/arch/arm/include/mutex.h I figured that ldrex/strex will be added eventually.

Actually, they are already in use.

You can emulate ldrexb/strexb with ldrex/strex so that isn't really a problem.

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