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Subject: Re: [boost] ARM thumb support in spinlock_gcc_arm.hpp
From: Michael Marcin (mike.marcin_at_[hidden])
Date: 2008-09-05 14:37:45

Jerry Napoli wrote:
> I'm trying to compile using boost 1_36_0 for ARMv6 Thumb for iPhone
> development. The compiler used is gcc 4.0.x supplied with the iphone sdk.
> I run into issues with the inline assembly inside
> boost/detail/spinlock_gcc_arm.hpp. It generates a SWP instruction which
> (AFAIK) is not supported in thumb mode. The gnu arm assembler gives me
> a 'bad instruction ...' error. I'm able to work around it by modifying
> spinlock.hpp to include spinlock_sp.hpp instead. But has anyone
> addressed spinlock support for armv6 thumb?

Sorry this is not an answer but why are you using thumb?
Does the iphone sdk force it?

While working on armv5 cell phone projects I found that in practice arm
was smaller and faster than thumb because many arm instructions took
more than 2 thumb instructions to emulate.


Michael Marcin

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