[Simh] Simh execution speed improvement

[Davis Johnson]

Davis Johnson wrote:

>Bailey, Scott wrote:
>  
>
>>... it is possible to compile using gcc with the "-fwhole-program
>>--combine" flags -- on paper, this presents the compiler with additional
>>opportunities for optimization.
>>
>>    
>>
>If the compiler is smart enough to do this, might it be smart enough to 
>inline without being asked? I really need to read the compiler 
>documentation again.
>
>  
>
-O3 (and higher, although -O3 seems to be as far as it goes, yet) does 
include --finline-functions. From 
http://gcc.gnu.org/onlinedocs/gcc-3.3.6/gcc/Optimize-Options.html#Optimize-Options 
:

    |-finline-functions|
        Integrate all simple functions into their callers. The compiler
        heuristically decides which functions are simple enough to be
        worth integrating in this way.

        If all calls to a given function are integrated, and the
        function is declared |static|, then the function is normally not
        output as assembler code in its own right.

        Enabled at level -O3.

Memory management (relocation and protection) on Interdata machines is 
fairly simple. My guess is that it is simple enough to be considered 
"simple functions" by the compiler. This probably explains the mystery. 
This may not be true when emulating a machine with more complex memory 
management.


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