Re: [Qemu-devel] [RFC PATCH v3 02/46] target/i386: Push rex_w into DisasContext

[Richard Henderson <richard.henderson@linaro.org>]

On 8/15/19 8:30 AM, Aleksandar Markovic wrote:
> 
> 15.08.2019. 04.13, "Jan Bobek" <jan.bobek@gmail.com
> <mailto:jan.bobek@gmail.com>> је написао/ла:
>>
>> From: Richard Henderson <rth@twiddle.net <mailto:rth@twiddle.net>>
>>
>> Treat this the same as we already do for other rex bits.
>>
>> Signed-off-by: Richard Henderson <rth@twiddle.net <mailto:rth@twiddle.net>>
>> ---
>>  target/i386/translate.c | 19 +++++++++++--------
>>  1 file changed, 11 insertions(+), 8 deletions(-)
>>
>> diff --git a/target/i386/translate.c b/target/i386/translate.c
>> index d74dbfd585..c0866c2797 100644
>> --- a/target/i386/translate.c
>> +++ b/target/i386/translate.c
>> @@ -44,11 +44,13 @@
>>  #define REX_X(s) ((s)->rex_x)
>>  #define REX_B(s) ((s)->rex_b)
>>  #define REX_R(s) ((s)->rex_r)
>> +#define REX_W(s) ((s)->rex_w)
>>  #else
>>  #define CODE64(s) 0
>>  #define REX_X(s) 0
>>  #define REX_B(s) 0
>>  #define REX_R(s) 0
>> +#define REX_W(s) -1
> 
> The commit message says "treat rex_w the same as other rex bits". Why is then
> REX_W() treated differently here?

"Treated the same" in terms of being referenced by a macro instead of a local
variable.  As for the -1, if you look at the rest of the patch you can clearly
see it preserves existing behaviour.

>> @@ -4503,6 +4504,7 @@ static target_ulong disas_insn(DisasContext *s,
> CPUState *cpu)
>>      s->rex_x = 0;
>>      s->rex_b = 0;
>>      s->rex_r = 0;
>> +    s->rex_w = -1;
>>      s->x86_64_hregs = false;
>>  #endif
>>      s->rip_offset = 0; /* for relative ip address */
>> @@ -4514,7 +4516,6 @@ static target_ulong disas_insn(DisasContext *s,
> CPUState *cpu)
>>      }
>>
>>      prefixes = 0;
>> -    rex_w = -1;


r~