Re: [pcre-dev] Question about sljit_emit_enter

Zoltan,

thanks very much!

the other question is:

     looks like float type is not necessary in JIT ?  those XXX_fop is 
not used ?

---
Jiong

on 2013/6/6 18:41, Zoltan Herczeg wrote:
> Hi,
>
> yes, your guess is right in both cases.
>
> On mips:
> 1 - for saving the return register
> 4 - excerpt form the MIPS ABI: In a non-leaf function the maximum number
> of bytes of arguments used to call other functions from the non-leaf
> function must be allocated. However, at least four words (16 bytes) must
> always be reserved, even if the maximum number of arguments to any called
> function is fewer than four words.
> In SLJIT we can pass maximum of 3, machine word sized arguments to a
> function.
>
> ARM has much less scratch registers than MIPS, and sometimes we need to
> use saved registers for scratch.
>
> Btw the JIT compiler has a separate repository, where additional test
> cases are available:
> http://sourceforge.net/projects/sljit/
>
> Regards,
> Zoltan
>
> "WANG.Jiong" <wong.kwongyuan@???> írta:
>> Hi All,>
>>
> I am trying to port PCRE to a VLIW processor and I am studing MIPS>
> backend to warm up with the code.>
> But the following things confused me:>
>>
> in sljit/sljitNativeMIPS_common.c:>
> 475 local_size += (saveds + 1 + 4) * sizeof(sljit_sw);>
> how does the "saveds + 1 + 4" comes ? I guess "1" means the extra return>
> address register, but what does "4" mean? the shadown area on mips stack ?>
> and I found ARM backend will push the last two scratch registers on>
> stack, while mips don't, could anyone give me some hint on this? just>
> because ARM don't have enough caller saved registers to be used as>
> scratch register?>
> thanks in advance !>
> --->
> Regards,>
> Jiong>
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