Shl: what changed

Revision 0 to 1. Removed lines have a minus sign; added lines have a plus sign.

Title: Shl

New		Line
1	+	Back to [[Reserved words]].
2	+
3	+	## Overview
4	+
5	+	The reserved word Shift left (shl) performs a left bit-shift operation, shifting the value by the amount of bits specified as an argument (opposite of [[Shr\|shr]]).
6	+
7	+	Example:
8	+
9	+	`Command is: 00000100 shl 2 (shift left 2 bits)`\
10	+	` `\
11	+	`Action is: 00000100 <- 00 (00 gets added to the right of the value; left 00 "disappears")`\
12	+	` `\
13	+	`Result is: 00010000`
14	+
15	+	## Clear a bit
16	+
17	+	``` pascal
18	+	function ClearBit( const aValue, aBitNumber : integer ) : integer;
19	+	begin
20	+	// sanity check supplied value
21	+	if (aBitNumber <0) or (aBitNumber >15) then
22	+	result :=0
23	+	else
24	+	// value ok
25	+	result := aValue and not( 1 shl aBitNumber );
26	+	end;
27	+	```
28	+
29	+	If you call ClearBit(%1111,1), then you get %1101 (The [[Binary numeral system\|binary number]] %1111 is 15 and %1101 = 13).
30	+
31	+	If you call ClearBit(13,2), then you get 9 (9 = %1001).
32	+
33	+	In this case, bits are numbered right to left from 0 to 15, bit 0 being the ones bit and bit 15 being the sign bit.
34	+
35	+	- [[Or\|Set a bit]]
36	+	- [[Xor\|Toggle a bit]]
37	+	- [[Bit manipulation]]
38	+	- [[$Bitpacking]]
39	+
40	+	---
41	+	From the Free Pascal wiki, page "Shl", as it stood on 2021-08-29 after a change by AndreasFilsinger, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's [[Licensing]] page. If you have concerns about this material, [message the admin](/wiki-contact).
42	+	Category: Code
43	+	Category: Operators