Prohibiting use of some registers in the GCC compiler

[Richard Earnshaw (lists)]

On 31/05/17 00:34, Nisal Menuka wrote:
> Hi,
> I would like to reserve some registers in ARM64 processor and prohibit
> the compiler from using them in any scenario.
> 
> For example: ARM64 Thirty-one 64-bit general-purpose registers X0-X30.
> I want to reserve register X30, and make sure when I compile any code
> using gcc, it won't use register X30 in any situation.
> 

You can't reserve x30, it's the link register and clobbered by call
instructions.

R.

> How can this be done? Any help would be greatly appreciated.
> 
> Thanks,
> Nisal
>