7.2 Variables

You can declare numeric, logical, or string variables using assembler directives.

The value of a variable can be changed as assembly proceeds. Variables are local to the assembler. This means that in the generated code or data, every instance of the variable has a fixed value.
The type of a variable cannot be changed. Variables are one of the following types:
  • Numeric.
  • Logical.
  • String.
The range of possible values of a numeric variable is the same as the range of possible values of a numeric constant or numeric expression.
The possible values of a logical variable are {TRUE} or {FALSE}.
The range of possible values of a string variable is the same as the range of values of a string expression.
Use the GBLA, GBLL, GBLS, LCLA, LCLL, and LCLS directives to declare symbols representing variables, and assign values to them using the SETA, SETL, and SETS directives.


a    SETA 100
L1   MOV R1, #(a*5) ; In the object file, this is MOV R1, #500
a    SETA 200       ; Value of 'a' is 200 only after this point. 
                    ; The previous instruction is always MOV R1, #500
     BNE L1         ; When the processor branches to L1, it executes 
                    ; MOV R1, #500
Related concepts
7.14 Numeric expressions
7.12 String expressions
7.3 Numeric constants
7.17 Logical expressions
Related reference
12.43 GBLA, GBLL, and GBLS
12.50 LCLA, LCLL, and LCLS
12.63 SETA, SETL, and SETS
Non-ConfidentialPDF file icon PDF versionARM DUI0379G
Copyright © 2007, 2008, 2011, 2012, 2014, 2015 ARM. All rights reserved.