Difference between revisions of "Not"

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= Boolean operation =
 
= Boolean operation =
  

Revision as of 07:07, 10 July 2013

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Boolean operation

Not produces a value of true if original value is false.

Truth table

A Not A
  false     true
  true     false  


Bitwise operation

Bitwise not sets the bit to 1 if corresponding bit is 0, and to 0 if bit is 1.

Ones' complement

 function OnesComplement ( const aValue : byte ): byte;
 begin
   result := Not AValue;
 end;

If you call OnesComplement(%10000000) then get %01111111 (%10000000 = 128 and %01111111 = 127). If you call OnesComplement(%00000111) then get 248 (248 = %11111000).


 function OnesComplement2 ( const aValue : shortint ): shortint;
 begin
   result := Not AValue;
 end;

If you call OnesComplement2(%00000010) then get %11111101 (%00000010 = 2 and %11111101 = -3 when type is shortint). If you call OnesComplement2(7) then get -8 (-8 = %11111000 when type is shortint and 7 = %00000111 ).


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