Re: [Qemu-devel] [PATCH v2] SPARC: Add and use CPU_FEATURE_CASA

[Fabien Chouteau]

On 02/13/2014 10:52 AM, Sebastian Huber wrote:
> The LEON3 processor has support for the CASA instruction which is
> normally only available for SPARC V9 processors.  Binutils 2.24
> and GCC 4.9 will support this instruction for LEON3.  GCC uses it to
> generate C11 atomic operations.
> 
> The CAS synthetic instruction uses an ASI of 0x80.  If TARGET_SPARC64 is
> not defined use a supervisor data load/store for an ASI of 0x80 in
> helper_ld_asi()/helper_st_asi().
> 

Hello Sebastian,

If I understand correctly, the difference with V1 is that ASI 0x80. Why
did you chose Supervisor data access against User data access? (I cannot
find documentation about 0x80 ASI)

Thanks,