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--- reference:lp0604 [2009/08/04 08:13]
don created
+++ reference:lp0604 [2010/01/17 22:19] (current)
don
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-====== 6.04 Miscellaneous System Commands ======
+====== 6.04 Binary & Logical Operations ======
-===== BEEP =====
+===== Binary Operators =====
-=== Function: ===
+Binary operations are used to test and set individual bits and bit combinations.  They are most often used when dealing with internal representation on computers.
-Generates a beep sound
-=== Syntax: ===
-  BEEP
-===== DELAY =====
+  =**Number Formats**
-=== Function: ===
+  =&h or 0x
-Delay for a specified amount of milliseconds. This 'delay' is also dependent on system clock.
+  :Prefix for hexadecimal constant (0x1F, &h3C)
-=== Syntax: ===
+  =&o or 0o
-  DELAY ms
+  :Prefix for octal constant (0o33, &o33)
+  =&b or 0b
+  :Prefix for binary constant (0b1010, &b1110)
-===== PAUSE =====
+The following operators are used. They are listed in priority order. Those that are in a group that is higher in the list take precedence over those in a group that is lower down the list.
-=== Function: ===
-Pauses the execution for a specified length of time, or until the user hits the keyboard.
-=== Syntax: ===
-  PAUSE [secs]
-===== ENVIRON Command =====
+  =**Operator**
-=== Function: ===
+  :**Usage**
-Adds a variable to or deletes a variable from the current environment variable-table.
+  =**Binary Operations**
-=== Syntax: ===
+  =%%<<, >>%%
-  ENViron expr
+  :bitwise shift left and shift right.\\
-  =expr
+b0011 %%<<%% 1 -> 0b0110\\
-  :A string expression of the form &quot;name=parameter&quot;
+b1100 %%>>%% 3 -> 0b0001
-  :If name already exists in the environment table, its current setting is replaced with the new setting. If name does not exist, the new variable is added.
+  =~
+  :bitwise NOT (~A).\\
+Result bit is 1 if operand A bit is 0 and vice versa, otherwise result bit is 0.\\
+~0b1100 -> 0b0011
+  =BAND or &
+  :bitwise AND (A AND B)\\
+Result bit is 1 if both operand bits are 1, otherwise result bit is 0.\\
+b1100 & 0b1010 -> 0b1000
+  =BOR or %%|%%
+  :bitwise OR (A OR B)\\
+Result bit is 1 if either operand bit is 1, otherwise result bit is 0.\\
+b1100 %%|%% 0b1010 -> 0b1110
+  =XOR
+  :bitwise XOR (A XOR B).\\
+Result bit is 1 if either A is 1 or B is 1 but not both(i.e. not the same), otherwise result bit is 0.\\
+b1100 XOR 0b1010 -> 0b0110
+  =EQV\\
+XNOR
+  :bitwise EQV/XNOR (NOT (A XOR B)).\\
+Result bit is 1 if both operand bits are the same, otherwise result bit is 0.\\
+b1100 EQV 0b1010 -&gt; 0b1001
+  =IMP
+  :bitwise IMP (NOT (A AND NOT B)).\\
+Result bit is 0 if first operand bit is 1 and second operand bit is 0, otherwise result bit is 1.\\
+b1100 IMP 0b1010 -&gt; 0b1011
+  =NAND
+  :bitwise NAND (NOT (A AND B))\\
+Result bit is 0 if both operand bits are 1, otherwise result bit is 0.\\
+b1100 NAND 0b1010 -> 0b0111
+  =NOR
+  :bitwise NOR (NOT (A OR B))\\
+Result bit is 1 if both operand bits are 0, otherwise result bit is 1.\\
+b1100 NOR 0b1010 -> 0b0001
-===== ENVIRON Function =====
-=== Function: ===
+===== Logical Operators =====
-Returns the value of a specified entry in the current environment table. If the parameter is empty (&quot;&quot;) then returns an array of the envirment variables (in var=value form)
+Logical operations are used to test conditions to determine what action a program should take.
-=== Syntax: ===
-  ENViron(var)
+  =**Operator**
-  =var
+  :**Usage**
-  :A string expression of the form &quot;var&quot;
+  =NOT or !
+  :Logical NOT (NOT false = true)
+  ==
+  :Equal
+  =&lt;&gt; or !=
+  :Not Equal
+  =<, >
+  :Less Than, Greater Than
+  =%%=<, =>, <=, >=%%
+  :Less Than or Equal, Greater than or Equal
+  =IN
+  :belongs to ... (see [[lp0409#The operator IN]])
+  =LIKE
+  :Regular expression match (see [[lp0409#The operator LIKE]])
+  =AND or &&
+  :Logical AND (A AND B)
+  =OR or %%||%%
+  :Logical OR (A OR B)
+===== Page Links =====
+|  &lt;= [[lp0603]]  | |  [[start]]  | |  [[lp0605]] =&gt;  |

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reference/lp0604.txt · Last modified: 2010/01/17 22:19 by don