Re: [Qemu-devel] [RFC 18/28] target-xtensa: implement exceptions

[Richard Henderson]

On 05/04/2011 09:33 AM, Richard Henderson wrote:
> This is a case where you almost certainly want to check this 
> condition inside QEMU and translate the opcode differently.
> 
> See cpu_get_tb_cpu_state, which sets bits in *flags.  These
> flags can then be checked in tb->flags while translating.
> At which point you'd avoid all the conditionalization on
> the value in PS here in check_privilege and merely issue
> the exception_cause.
> 
> The ARM port is a good example for testing these sorts of bits.

Actually, while the tb flags are useful, privileged instructions
are usually checked by testing mmu_index, since we already have
to generate different code for the TB based on which TLB entry we
need to access.


r~