Re: [Qemu-devel] Question about gen_jmp_tb

[Alex Bennée]

Jack Biggs writes:

> Hi Richard, thanks for your help.
>
> Which instruction, then, I should add my gen_helper to in order for it 
> to be called at the end of each basic block, as I've previously stated? 
> Is there a way I can generically have this change apply to every target?
>
> Jack
>
> On 05/30/2014 06:25 PM, Richard Henderson wrote:
>> On 05/30/2014 01:56 AM, Jack Biggs wrote:
>>> Hi all,
>>>
>>> I'm trying to add some arbitrary code to the end of each translation block, 
>>> and
>>> I wanted to confirm my suspicion that each translation block ends in
>>> a jmp

When you say arbitrary code what do you mean? Are you wanting to put
backend specific code there or a common post-amble of tcg ops?

Can you give a bit more detail about your use case?

>>> instruction, and that each translation block ends (or jumps to another TB) 
>>> with
>>> the call to gen_jmp_tb. My guest is i386, but if this is 
>>> architecture-specific
>>> I'd like to know more about per-target semantics.
>> No, not every tb ends with gen_jmp_tb.  Indeed, only those for which we have 
>> an
>> immediate address end that way.  Plenty of tb's end with indirect branches, 
>> or
>> for a variety of other reasons.
>>
>> Certainly gen_jmp_tb is specific to the i386 translator.
>>
>>
>> r~

-- 
Alex Bennée