RE: int vs binary questions

[cozzi@xxxxxxxxx]

   Hans,
    
   >>performance difference disappears with optimization
    
   Oh great! Now I have to tell people to use optimization. <tic>
   I've always said, if you must use optimization use *BASIC with RPG as
   using *FULL will take more time to compile than you will every save in
   runtime performance. :)
    
   -Bob

    

     -------- Original Message --------
     Subject: Re: int vs binary questions
     From: "Hans Boldt" <boldt@xxxxxxxxxx>
     Date: Mon, February 09, 2004 1:09 pm
     To: rpg400-l@xxxxxxxxxxxx

     cozzi@xxxxxxxxx wrote:

     >    Hans,
     >    That's all well and good, but...
     >    1) Why is DDS limited to 2 and 4 byte binaries and seems to use the
     >    RPG-like declaration for them (or has that changed?)
     >    2) Why would the timing of int->int copy be slower than Bin->Bin in
     RPG IV
     >    as was reported here earlier today?
     >    

     1) DDS is NOT limited to 2 and 4 byte binaries. DDS also supports 8 byte
     binaries.

     2) Why did Steve report faster timings on bin->bin copy compared to
     int->int copy?  First, on a simple "EVAL B1=B2;" copy from binary to
     binary where both variables have the same size, no conversion happens.
     In W-Code, we do just a LOD and STR. For an assignment "EVAL I1=I2;", it
     actually is a little bit more complicated. If I1 and I2 are defined as
     20I0, there's a LOD and STR which runs at around the same speed as the
     binary. However, if the source argument is not 20I0, the compiler emits
     a "convert to 8-byte integer" instruction first, and that tends to slow
     things down a little bit. The performance difference disappears with
     optimization, however.

     Cheers! Hans

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