RE: Humorous Enhancements: now

["Kahn, David [JNJFR]" <DKahn1@xxxxxxxxxxxxx>]

Scott,

You can use BITON and BITOF to emulate the logical operators OR AND and XOR
much more efficiently than that. You don't need to do a TESTB or use
indicators. Assume the operands are in single byte fields A and B and you
want the result in field C without altering A or B.

To perform OR:
        
     C                     MOVE A         C       1
     C                     BITONB         C        

To perform AND:
     
     C                     MOVE A         C       1
     C                     MOVE A         X       1
     C                     BITOFB         X        
     C                     BITOFX         C        

To perform XOR:
       
     C                     MOVE A         C       1
     C                     MOVE B         X       1
     C                     BITOFA         X        
     C                     BITOFB         C        
     C                     BITONX         C        

Still not as efficient as directly implemented operations, but not bad.

Dave Kahn
Johnson & Johnson International (Ethicon) France
Phone : +33 1 55 00 3180
Email :  dkahn1@jnjfr.jnj.com (work)
           dkahn@cix.co.uk      (home)



-----Message d'origine-----
De: Scott Klement [mailto:infosys@klements.com]
Date: 06 August 1999 06:43
À: RPG400-L@midrange.com
Objet: Re: Humorous Enhancements


YES!!! YES!!!  We need some real bitwise operations.
(this probably doesn't surprise you coming from me)

I've had to write special routines that go through a string of
bytes, check every single bit with TESTB, compare it against the
same bit pos in a different string, and finally do a manual XOR.
(by checking the result indicators of testb) and then finally
using BITON to set the string of bytes to the result.

Doesnt perform real well when compared to a real XOR operation.
I'm sure the CPU can do XOR at the machine code level...  so it seems
silly to have to go that far to make an XOR. :)
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