ARM VERSION 1.2 Symbols, Numeric constants on, Labels on, Local labels on, Symbol naming rules

Assembler Reference

3.5Symbols

You can use symbols to represent variables, addresses, and numeric constants. Symbols representing addresses are also called labels. See:

•Variables on page 3-13

•Numeric constants on page 3-13

•Labels on page 3-15

•Local labels on page 3-16.

3.5.1Symbol naming rules

The following general rules apply to symbol names:

•You can use uppercase letters, lowercase letters, numeric characters, or the underscore character in symbol names.

•Do not use numeric characters for the first character of symbol names, except in local labels (see Local labels on page 3-16).

•Symbol names are case-sensitive.

•All characters in the symbol name are significant.

•Symbol names must be unique within their scope.

•Symbols must not use built-in variable names or predefined symbol names (see Predefined register and coprocessor names on page 3-9 and Built-in variables on page 3-10).

•Symbols must not use the same name as instruction mnemonics or directives. If you use the same name as an instruction mnemonic or directive, use double bars to delimit the symbol name. For example:

ASSERT

The bars are not part of the symbol.

If you need to use a wider range of characters in symbols, for example, when working with compilers, use single bars to delimit the symbol name. For example:

.text

The bars are not part of the symbol. You cannot use bars, semicolons, or newlines within the bars.

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