ARM VERSION 1.2 - page 102

Assembler Reference

3.6.9 Operator precedence

The assembler includes an extensive set of operators for use in expressions. Many of the

operators resemble their counterparts in high-level languages such as C (see Unary

operators on page 3-26 and Binary operators on page3-28).

There is a strict order of preceden ce in their evaluation:

1. Expressions in parentheses are evaluated first.

2. Operators are applied in precedence order.

3. Adjacent unary operators are evaluated from right to left.

4. Binary operators of equal precedence are evaluated from left to right.

Note

The order of precedence is not exactly the same as in C.

For example,

(1 + 2 :SHR; 3)

evaluates as

(1 + (2 :SHR: 3))

= 1 in

armasm

. The

equivalent expression in C evaluates as

((1 + 2) >> 3)

= 0.

You are recommended to use brackets to make the precedence explicit.

Table3-2 shows the order of precedence of operators in

armasm

, and a comparison with

the order in C.

If your code contains an expression which would parse differently in C,

armasm

normally

gives a warning:

A1466W: Operator precedence means that expression would evaluate differently in C

The warning is not given if you use the

-unsafe

command line option.

Table3-2 Operator precedence in armasm

armasm precedence equivalent C operators

unary operators unary operators

* / :MOD

* / %

string manipulation n/a

:SHL: :SHR: :ROR: :ROL: << >>