Re: [boost] ARM thumb support in spinlock_gcc_arm.hpp

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.

Thanks,

Michael Marcin