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

[Sebastian Huber]

Hello,

On 2013-11-26 15:04, 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.
> ---
>   target-sparc/cpu.c         |    3 +-
>   target-sparc/cpu.h         |    4 ++-
>   target-sparc/helper.h      |    4 ++-
>   target-sparc/ldst_helper.c |   26 +++++++++++++-----------
>   target-sparc/translate.c   |   47 ++++++++++++++++++++++++++++---------------
>   5 files changed, 52 insertions(+), 32 deletions(-)
[...]

this patch doesn't work since the ASI 0x80 used for the synthetic CAS 
instruction is not implemented in helper_ld_asi() for !TARGET_SPARC64.

I tried to add a

    case 0x80: /* Primary */
        {
            switch (size) {
            case 1:
                ret = ldub_raw(addr);
                break;
            case 2:
                ret = lduw_raw(addr);
                break;
            case 4:
                ret = ldl_raw(addr);
                break;
            default:
            case 8:
                ret = ldq_raw(addr);
                break;
            }
        }
        break;

but this results in a Qemu segmentation fault.

--
Sebastian Huber, embedded brains GmbH

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