ARM VERSION 1.2 - Manual (Page 91)

Assembler Reference
ARM DUI 0068B Copyright © 2000, 2001 ARM Limited. All rights reserved. 3-13
3.5.2 Variables
The value of a variable can be changed as assembly proceeds. Variables are of three
types:
• numeric
• logical
• string.
The type of a variable cannot be changed.
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 (see Numeric constants and
Numeric expressions on page 3-20).
The possible values of a logical variable are {TRUE} or {FALSE} (see Logical expressions
on page 3-23).
The range of possible values of a string variable is the same as the range of values of a
string expression (see String expressions on page 3-19).
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. See:
• GBLA, GBLL, and GBLS on page 7-4
• LCLA, LCLL, and LCLS on page 7-6
• SETA, SETL, and SETS on page 7-7.
3.5.3 Numeric constants
Numeric constants are 32-bit integers. You can set them using unsigned numbers in the
range 0 to 2
32 – 1, or signed numbers in the range –2 31 to 2 31 – 1. However, the
assembler makes no distinction between –n and 2 32 – n. Relational operators such as >=
use the unsigned interpretation. This means that 0 > –1 is {FALSE} .
Use the EQU directive to define constants (see EQU on page 7-57). You cannot change
the value of a numeric constant after you define it.
See also Numeric expressions on page 3-20 and Numeric literals on page 3-21.