Re: [PATCH 1/2] target/xtensa: Implement xtensa_isa_is_big_endian()

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

Hi Max,

On 6/12/24 13:35, Max Filippov wrote:
> On Thu, Dec 5, 2024 at 3:24 PM Philippe Mathieu-Daudé <philmd@linaro.org> wrote:
>> Xtensa internal fields are opaque, only accessible by
>> the Xtensa libisa. Implement xtensa_isa_is_big_endian()
>> to get vCPU endianness. This should be implemented in
>> libisa, not QEMU, but I couldn't figure out where to
>> contribute this.
> 
> This is a beautified version of what xtensa has in binutils, but
> binutils is also
> just another user of that internal Tensilica library. Perhaps I should make
> an artificial "upstream" for this library just to track this kind of changes.
> Let me look at it.

Could you add this method to the Tensilica library?

> 
>> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
>> ---
>>   include/hw/xtensa/xtensa-isa.h | 1 +
>>   target/xtensa/xtensa-isa.c     | 7 +++++++
>>   2 files changed, 8 insertions(+)
>>
>> diff --git a/include/hw/xtensa/xtensa-isa.h b/include/hw/xtensa/xtensa-isa.h
>> index a289531bdc8..1cb8e6ccb66 100644
>> --- a/include/hw/xtensa/xtensa-isa.h
>> +++ b/include/hw/xtensa/xtensa-isa.h
>> @@ -829,6 +829,7 @@ const char *xtensa_funcUnit_name(xtensa_isa isa, xtensa_funcUnit fun);
>>
>>   int xtensa_funcUnit_num_copies(xtensa_isa isa, xtensa_funcUnit fun);
>>
>> +bool xtensa_isa_is_big_endian(xtensa_isa isa);
> 
> This file doesn't include stdbool.h and other boolean functions in it
> (e.g. xtensa_opcode_is_branch()) return int. I'd suggest sticking with
> that. With that change:
> 
> Acked-by: Max Filippov <jcmvbkbc@gmail.com>
> 
>>   #ifdef __cplusplus
>>   }
>> diff --git a/target/xtensa/xtensa-isa.c b/target/xtensa/xtensa-isa.c
>> index 630b4f9da1b..36eb4bcf3d4 100644
>> --- a/target/xtensa/xtensa-isa.c
>> +++ b/target/xtensa/xtensa-isa.c
>> @@ -1741,3 +1741,10 @@ int xtensa_funcUnit_num_copies(xtensa_isa isa, xtensa_funcUnit fun)
>>       CHECK_FUNCUNIT(intisa, fun, XTENSA_UNDEFINED);
>>       return intisa->funcUnits[fun].num_copies;
>>   }
>> +
>> +bool xtensa_isa_is_big_endian(xtensa_isa isa)
>> +{
>> +    xtensa_isa_internal *intisa = (xtensa_isa_internal *)isa;
>> +
>> +    return intisa->is_big_endian;
>> +}
>