Detailed explanation of Delphi's bitwise operations-reply to the "Beginner's assembly" question

Source:
Http://www.cnblogs.com/del/archive/2008/04/02/1055762.html#1134153
Http://www.cnblogs.com/del/archive/2008/04/02/1055648.html#1134081

Delphi has six bitwise operators: Not and or xor shr shl;
The not and or XOR is also called a logical operator. In fact, the functions are the same, because no matter what data is chased, it is a combination of 0 and 1;
In Delphi embedded assembly, there should be no difference (Embedded Assembly is still learning, not familiar ).

The following method can be used to test the example below: http://www.cnblogs.com/del/archive/2008/03/09/1097845.html

Unit unit1; interfaceuses windows, messages, sysutils, variants, classes, graphics, controls, forms, dialogs, stdctrls; Type tform1 = Class (tform) button1: tbutton; button2: tbutton; button3: tbutton; button4: tbutton; button5: tbutton; button6: tbutton; Procedure processing (Sender: Taobao); Procedure processing (Sender: tobject ); procedure button4click (SE Nder: tobject); Procedure button5click (Sender: tobject); Procedure button6click (Sender: tobject); end; var form1: tform1; implementation {$ R *. DFM} const W1: Word = 61680; {binary representation: 11110000 11110000} W2: Word = 3855; {binary representation: 00001111 00001111} var W: word; {not operation, only one operation count} procedure tform1.button1click (Sender: tobject); begin W: = Not W1; {not is bitwise (to every bit of binary) reverse retrieval} {11110000 11110000 00001111 after reverse retrieval:} {0000111 1} showmessage (inttostr (w); {3855} end; {and operation, requires two operation numbers} procedure tform1.button2click (Sender: tobject); begin W: = W1 and W2; {and is to compare two arithmetic operations by bit. 1 returns 1, and 0} {W1: 11110000 11110000 and} {W2: 00001111 00001111 returns 1, so return:} {W: 00000000 00000000} showmessage (inttostr (w); {0} end; {or operation, two operations are required} procedure tform1.button3click (Sender: tobject ); begin W: = W1 or W2; {and is to compare two arithmetic values by bit. If one of them is 1, 1 is returned. 0 returns 0} {W1: 11110000 11110000 and} {W2: 00001111 00001111 or, then returns :}{ W: 11111111 11111111} showmessage (inttostr (w )); {65535} end; {XOR operation, requires two operation numbers} procedure tform1.button4click (Sender: tobject); begin W: = W1 or W2; {and is to compare the two operation numbers by bit, 1 is returned only when there are two differences. If both are 0 or 1, 0} {W1: 11110000 11110000 and} {W2: 00001111 00001111 XOR are returned, :}{ W: 11111111 11111111} showmessage (inttostr (w); {65535; the number of two instances is not good, and XOR and or Significant difference} end; {SHR operation, only one operation number} procedure tform1.button5click (Sender: tobject); begin W: = W1 SHR 1; {SHR is shifted right by bit, SHR 1 is shifted to one right} {W1: 11110000 11110000 shifted to one right followed by :}{ W: * 1111000 before * 0} showmessage (inttostr (w )); {30840} {Likewise, several digits can be moved, for example, 3} W: = W1 SHR 3; showmessage (inttostr (w )); {7710} {W1 SHR 3 is equivalent to the 3rd power of W1 Div 2} W: = W1 Div 8; showmessage (inttostr (w); {7710} end; {SHL operation, only one operation count} procedure tform1. Button6click (Sender: tobject); var I: integer; begin W: = W1 SHL 1; {SHR is shifted left by bit} {W1: 11110000 11110000 shifted left by one after :} {W: 1110000 111100000} showmessage (inttostr (w); {57824} {shifts three places left} W: = W1 SHL 3; showmessage (inttostr (w )); {34688} {W1 SHL 3 is equivalent to the 3rd power of W1 * 2} W: = W1 * 8; showmessage (inttostr (w )); {34688} {Note the following question: why is it small after W1 * 8 ?} {Because the previously defined W is of the Word type, its size is only 2 bytes (16 bits in binary) and will be ignored if it is exceeded} {if it is changed to 32 bits (4 bytes) the actual result is:} I: = W1 SHL 3; showmessage (inttostr (I); {493440} I: = W1 * 8; showmessage (inttostr (I); {493440} end; end.