Re: [Qemu-devel] classic emulator Vs QEMU-TCG

[Andreas Färber]

Hi,

Am 17.12.2010 um 10:47 schrieb Stefano Bonifazi:

> I've got an explanation from a C guru :)
>
> > ((long REGPARM (*)(void *))code_gen_prologue)(tb_ptr)
> > ---------
> > (long REGPARM (*)(void *)) is a type: a pointer pointing to a  
> > function, which takes one (void*) parameter. code_gen_prologue is  
> > an>array, array's name when used is considered to be a pointer to  
> > its first element, thus you are casting here pointer to the first  
> > byte of>array to pointer to function (...).
> > Ellipsis with tb_ptr mean 'call function under this address and  
> > pass there whatever tb_ptr is'
>
> Now everything is very clear for me :)
> I do know pointer to functions, and if I had got:
>
> > long REGPARM (*myfunc)(void *)
>
> I would have recognized it.. but removing the function pointer name,  
> leaving only the * was enough for me to be lost :[

Feel free to take the next step then and read CODING_GUIDELINES to  
create and submit your first Git patch to make the code more readable  
for others. Introducing a typedef for the cast might not be a bad idea.

> also the definition of code_gen_prologue was tricky:
> > uint8_t code_gen_prologue[1024] code_gen_section;
> that code_gen_section at first confused my idea of a normal variable  
> definition as "type identifier" .. until I found out it was a define  
> for a compiler directive (alignment) :[

Would capitalizing code_gen_section have helped to recognize it as a  
preprocessor define? Another patch idea. :)

Regards,
Andreas