Difference between revisions of "Shl"
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== Overview == | == Overview == | ||
| − | '''Sh'''ift '''l'''eft ('''shl''') performs a left bit-shift operation (opposite | + | '''Sh'''ift '''l'''eft ('''shl''') performs a left bit-shift operation (opposite of [[Shr|shr]]). |
E.g | E.g | ||
| − | Command is: 00000100 | + | Command is: 00000100 shl 2 |
| − | Action is: 00000100 <- 00 | + | Action is: 00000100 <- 00 (00 gets added to the right of the value) |
Result is: 00010000 | Result is: 00010000 | ||
| Line 17: | Line 17: | ||
function ClearBit( const aValue, aBitNumber : integer ) : integer; | function ClearBit( const aValue, aBitNumber : integer ) : integer; | ||
begin | begin | ||
| − | + | result := aValue and not( 1 shl aBitNumber ); | |
end; | end; | ||
</syntaxhighlight> | </syntaxhighlight> | ||
Revision as of 10:32, 15 October 2014
Overview
Shift left (shl) performs a left bit-shift operation (opposite of shr).
E.g
Command is: 00000100 shl 2 Action is: 00000100 <- 00 (00 gets added to the right of the value) Result is: 00010000
Clear a bit
function ClearBit( const aValue, aBitNumber : integer ) : integer;
begin
result := aValue and not( 1 shl aBitNumber );
end;If you call ClearBit(%1111,1), then you get %1101 (%1111 = 15 and %1101 = 13).
If you call ClearBit(13,2), then you get 9 (9 = %1001) .
