Assembler Syntax

The SunOS 5.x SPARC assembler takes assembly language programs, as specified in this document, and produces relocatable object files for processing by the SunOS 5.x SPARC link editor. The assembly language described in this document corresponds to the SPARC instruction set defined in the SPARC Architecture Manual (Version 8 and Version 9) and is intended for use on machines that use the SPARC architecture.

This chapter is organized into the following sections:

• "2.1 Syntax Notation"

• "2.2 Assembler File Syntax"

• "2.3 Lexical Features"

• "2.4 Assembler Error Messages"

2.1 Syntax Notation

In the descriptions of assembly language syntax in this chapter:

• Brackets ([ ]) enclose optional items.

• Asterisks (*) indicate items to be repeated zero or more times.

• Braces ({ }) enclose alternate item choices, which are separated from each other by vertical bars (|).

• Wherever blanks are allowed, arbitrary numbers of blanks and horizontal tabs may be used. Newline characters are not allowed in place of blanks.

2.2 Assembler File Syntax

The syntax of assembly language files is:

[line]*

2.2.1 Lines Syntax

The syntax of assembly language lines is:

[statement [ ; statement]*] [!comment] 

2.2.2 Statement Syntax

The syntax of an assembly language statement is:

[label:] [instruction] 

where:

label

is a symbol name.

instruction

is an encoded pseudo-op, synthetic instruction, or instruction.

2.3 Lexical Features

This section describes the lexical features of the assembler syntax.

2.3.1 Case Distinction

Uppercase and lowercase letters are distinct everywhere except in the names of special symbols. Special symbol names have no case distinction.

2.3.2 Comments

A comment is preceded by an exclamation mark character (!); the exclamation mark character and all following characters up to the end of the line are ignored. C language-style comments (``/*...*/'') are also permitted and may span multiple lines.

2.3.3 Labels

A label is either a symbol or a single decimal digit n (0...9). A label is immediately followed by a colon ( : ).

Numeric labels may be defined repeatedly in an assembly file; normal symbolic labels may be defined only once.

A numeric label n is referenced after its definition (backward reference) as nb, and before its definition (forward reference) as nf.

2.3.4 Numbers

Decimal, hexadecimal, and octal numeric constants are recognized and are written as in the C language. However, integer suffixes (such as L) are not recognized.

For floating-point pseudo-operations, floating-point constants are written with 0r or 0R (where r or R means REAL) followed by a string acceptable to atof(3); that is, an optional sign followed by a non-empty string of digits with optional decimal point and optional exponent.

The special names 0rnan and 0rinf represent the special floating-point values Not-A-Number (NaN) and INFinity. Negative Not-A-Number and Negative INFinity are specified as 0r-nan and 0r-inf.

Note - The names of these floating-point constants begin with the digit zero, not the letter "O."

2.3.5 Strings

A string is a sequence of characters quoted with either double-quote mark (") or single-quote mark (') characters. The sequence must not include a newline character. When used in an expression, the numeric value of a string is the numeric value of the ASCII representation of its first character.

The suggested style is to use single quote mark characters for the ASCII value of a single character, and double quote mark characters for quoted-string operands such as used by pseudo-ops. An example of assembly code in the suggested style is:

add %g1,'a'-'A',%g1 ! g1 + ('a' - 'A') --> g1 

The escape codes described in Table 2-1, derived from ANSI C, are recognized in strings.

Table 2-1

2.3.6 Symbol Names

The syntax for a symbol name is:

{ letter | _ | $ | . }   { letter | _ | $ | . | digit }* 

In the above syntax:

• Uppercase and lowercase letters are distinct; the underscore ( _ ), dollar sign ($), and dot ( . ) are treated as alphabetic characters.

• Symbol names that begin with a dot ( . ) are assumed to be local symbols. To simplify debugging, avoid using this type of symbol name in hand-coded assembly language routines.

• The symbol dot ( . ) is predefined and always refers to the address of the beginning of the current assembly language statement.

• External variable names beginning with the underscore character are reserved by the ANSI C Standard. Do not begin these names with the underscore; otherwise, the program will not conform to ANSI C and unpredictable behavior may result.