Re: [Qemu-devel] [PATCH v1 01/22] target-arm: A64: Add friendly logging of PSTATE A and I flags

[Peter Maydell]

On 6 May 2014 07:08, Edgar E. Iglesias <address@hidden> wrote:
> From: "Edgar E. Iglesias" <address@hidden>
>
> Signed-off-by: Edgar E. Iglesias <address@hidden>
> ---
>  target-arm/translate-a64.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/target-arm/translate-a64.c b/target-arm/translate-a64.c
> index b62db4d..4f8246f 100644
> --- a/target-arm/translate-a64.c
> +++ b/target-arm/translate-a64.c
> @@ -137,8 +137,10 @@ void aarch64_cpu_dump_state(CPUState *cs, FILE *f,
>              cpu_fprintf(f, " ");
>          }
>      }
> -    cpu_fprintf(f, "PSTATE=%08x (flags %c%c%c%c)\n",
> +    cpu_fprintf(f, "PSTATE=%08x (flags %c%c%c%c%c%c)\n",
>                  psr,
> +                psr & PSTATE_A ? 'A' : '-',
> +                psr & PSTATE_I ? 'I' : '-',
>                  psr & PSTATE_N ? 'N' : '-',
>                  psr & PSTATE_Z ? 'Z' : '-',
>                  psr & PSTATE_C ? 'C' : '-',

Why A and I ? In particular in QEMU the A bit is always zero
because we don't do System Errors (aka asynchronous
external aborts), and it's weird to show I but not F. The
idea of splitting out NZCV is really that (as with the A32/T32
state dump) they're the most useful bits for immediately
figuring out code flow); anything else you can fish out of
the hex value by hand if you really need it. I think you can
make a case for "decode only a small set of key bits" or
for "completely decode the whole register", but I'm not
sure adding only two more bits makes sense.

thanks
-- PMM