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From: Peter Maydell <peter.maydell@linaro.org>
Date: Tue, 26 Nov 2013 21:02:17 +0000
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Subject: Re: [Qemu-devel] [PATCH] SPARC: Fix LEON3 power down instruction
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To: Sebastian Huber <sebastian.huber@embedded-brains.de>
Cc: Ronald Hecht <ronald.hecht@gmx.de>, Blue Swirl <blauwirbel@gmail.com>, QEMU Developers <qemu-devel@nongnu.org>, Fabien Chouteau <chouteau@adacore.com>

On 25 November 2013 14:22, Sebastian Huber
<sebastian.huber@embedded-brains.de> wrote:
> The env->pc is not necessarily up-to-date in the helper function.  Use
> the program counter of the disassembly context instead.
>
> Signed-off-by: Sebastian Huber <sebastian.huber@embedded-brains.de>
> ---
>  target-sparc/helper.c    |    6 +++---
>  target-sparc/helper.h    |    2 +-
>  target-sparc/translate.c |    3 ++-
>  3 files changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/target-sparc/helper.c b/target-sparc/helper.c
> index e70d1bc..50912ff 100644
> --- a/target-sparc/helper.c
> +++ b/target-sparc/helper.c
> @@ -314,14 +314,14 @@ target_ulong helper_tsubcctv(CPUSPARCState *env, target_ulong src1,
>  }
>
>  #ifndef TARGET_SPARC64
> -void helper_power_down(CPUSPARCState *env)
> +void helper_power_down(CPUSPARCState *env, uint32_t pc)
>  {
>      CPUState *cs = CPU(sparc_env_get_cpu(env));
>
>      cs->halted = 1;
>      env->exception_index = EXCP_HLT;
> -    env->pc = env->npc;
> -    env->npc = env->pc + 4;
> +    env->pc = pc + 4;
> +    env->npc = pc + 8;
>      cpu_loop_exit(env);

This seems a bit of an odd way to do this. I think most of
the frontends have the generated code do a sync-up of the
PC before calling the helper.

-- PMM