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Re: question about allocating local variable
Hi Prawit,
>And I will be appreciate if you could tell me why it gonna be that way.
I presume it is due to allocated space for register backing stores.
Granted, in lovingly hand-crafted assembly, you may dispense with over
reserved stack space through meticulous care.
In this situation, GCC seems to over-allocate the stack beyond what it
strictly needs (moreso than just alignment). Considering that the small
routine I wrote is a leaf-node (doesn't call any other subroutines).
>gcc 2.96 on x86
There is no "GCC 2.96" -- there's a Red Hat 2.96, which is a maverick /
rogue release. Red Hat 2.96 is not supported in this forum; it may be
supported by Red Hat.
That being said, GCC 3.3.1 on Cygwin / WinNT has the same behavior.
You may want to try the current releases of GCC, either GCC 3.3.4 or GCC 3.4.0.
>And asm code are the same no matter what you gonna optimized or not.
Okay, I've confirmed that with -O0 and -O3 on my platform.
--Eljay