Online HelpPC 2.10      Quick Reference Utility     Copyright 1991 David Jurgens

 
                       CMPXCHG - Compare and Exchange                       
                                                                                
        Usage:  CMPXCHG dest,src  (486+)                                        
        Modifies flags: AF CF OF PF SF ZF                                       
                                                                                
                                                                                
        Compares the accumulator (8-32 bits) with "dest".  If equal the         
        "dest" is loaded with "src", otherwise the accumulator is loaded        
        with "dest".                                                            
                                                                                
                                                                                
                                 Clocks                 Size                    
        Operands         808x  286   386   486          Bytes                   
                                                                                
        reg,reg           -     -     -     6             2                     
        mem,reg           -     -     -     7             2                     
                                                                                
                                                                                
        - add 3 clocks if the "mem,reg" comparison fails                        
        - see Instruction Timing                                                
                                                                                
                                                                                
 

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