BIT的操作

位操作，Bit操作： shr，and
如读第三位：( x shr 3 ) and 1
/// Check the bit is 0 or 1? 1:True,0:False
function CheckBit(const val: DWORD; const TheBit: byte): boolean;
begin
result := (val and (1 shl TheBit)) <> 0;
end;
/// Set bit 1
function SetBitOn(const val: DWORD; const TheBit: byte): DWORD;
begin
result := val or (1 shl TheBit);
end;
/// Set bit 0
function SetBitOff(const val: DWORD; const TheBit: byte): DWORD;
begin
result := val and ((1 shl TheBit) xor $FFFFFFFF);
end;
/// Toggle the bit,1-->0 ,0-->1
function ToggleBit(const val: DWORD; const TheBit: byte): DWORD;
begin
result := val xor (1 shl TheBit);
end;