Help with stack layout in SPARC.

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Article #42322

#42322

From: Varadarajan
Date: Tue, 12 Dec 1995 00:00

27 lines
1635 bytes

Hi all,

I tried posting this yesterday, but never showed up in my news
group. So I am trying my luck again.

This is an extract from sparc.h file from gcc...
/* Actual top-of-stack address is 92/136 greater than the contents of the
   stack pointer register for !v9/v9.  That is:
   - !v9: 64 bytes for the in and local registers, 4 bytes for structure return
     address, and 24 bytes for the 6 register parameters.
   - v9: 128 bytes for the in and local registers + 8 bytes reserved.  */

But when I see the output of assembly programs that are generated by
gcc, I happen to get 
save %sp, -112, %sp... (occassionally even -104)

Now what is this extra 20 bytes used for?? Am I missing something very
silly and stupid???
Thanks for the help,
Best Regards,

------------------------------------------------------------------------
| Varadarajan.T.S.            |  It's not an optical illusion, it just |
| M.S. Comp Science           |              looks like one.           |
| tsv@cs.umanitoba.ca         |         #include "std_disclaimer.h"    |
------------------------------------------------------------------------

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From: tsv@nickel.cs.umanitoba.ca (Varadarajan)
Subject: Help with stack layout in SPARC.
Date: 1995/12/12
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