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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