Re: [Qemu-devel] [PATCH] target-i386: set CC_OP to CC_OP_EFLAGS in cpu_load_eflags

[Paolo Bonzini <pbonzini@redhat.com>]

Il 15/05/2014 19:30, Richard Henderson ha scritto:
> On 05/15/2014 10:04 AM, Paolo Bonzini wrote:
>> There is no reason to keep that out of the function.  The comment refers
>> to the disassembler's cc_op state rather than the CPUState field.
>
> Yes, but...
>
>> -/* NOTE: CC_OP must be modified manually to CC_OP_EFLAGS */
>> +/* NOTE: set CC_OP to CC_OP_EFLAGS after calling a helper that uses this! */
>>  static inline void cpu_load_eflags(CPUX86State *env, int eflags,
>>                                     int update_mask)
>>  {
>>      CC_SRC = eflags & (CC_O | CC_S | CC_Z | CC_A | CC_P | CC_C);
>> +    CC_OP = CC_OP_EFLAGS;
>>      env->df = 1 - (2 * ((eflags >> 10) & 1));
>
> ... we'd do well to reflect that in the comment here, rather than
> in the commit message.  Because by itself it looks like the comment
> is out of date.

That's what I tried to do, but my wording was awful.

> /* NOTE: the translator must set DisasContext.cc_op to CC_OP_EFLAGS
>    after generating a call to a helper that uses this.  */

Much better.

>> --- a/target-i386/svm_helper.c
>> +++ b/target-i386/svm_helper.c
>> @@ -260,7 +260,6 @@ void helper_vmrun(CPUX86State *env, int aflag, int next_eip_addend)
>>                                    env->vm_vmcb + offsetof(struct vmcb,
>>                                                            save.rflags)),
>>                      ~(CC_O | CC_S | CC_Z | CC_A | CC_P | CC_C | DF_MASK));
>> -    CC_OP = CC_OP_EFLAGS;
>>
>>      svm_load_seg_cache(env, env->vm_vmcb + offsetof(struct vmcb, save.es),
>>                         R_ES);
>> --
>
> I see two sets of CC_OP in svm_helper.c.  Missed one?

Yes.

Paolo