__ARM_ARCH_2__

Richard Earnshaw rearnsha@arm.com
Thu Aug 8 15:35:00 GMT 2013


On 08/08/13 08:20, zhaobin xv wrote:
> Hi
> 
> In linux/arch/arm/boot/
> compressed/head.S:
> 
> 
> #ifndef __ARM_ARCH_2__
>         /*
>          * Booting from Angel - need to enter SVC mode and disable
>          * FIQs/IRQs (numeric definitions from angel arm.h source).
>          * We only do this if we were in user mode on entry.
>          */
>         mrs    r2, cpsr        @ get current mode
>         tst    r2, #3            @ not user?
>         bne    not_angel
>         mov    r0, #0x17        @ angel_SWIreason_EnterSVC
>         swi    0x123456        @ angel_SWI_ARM
> 
> 
> I don't know what the"__ARM_ARCH_2__" mean?
> "__ARM_ARCH_2__" is definded by gcc or definded byarmlinux?
> where does it come from? what does it want to do?
> 
> 
> 

__ARM_ARCH_2__ is defined by GCC when compiling for an ARM cpu that
implements the ARMv2 revision of the architecture.  ARMv2 is now
obsolete and you'll almost certainly not want to support that now.

R.



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