A statement is a combination of mnemonics, operands, and comments the defines the object code to be created at assembly time. Each line of source code contains a single statement.

##### Syntax

Assembler statements take the form:

> [label] [operation] [operands] [comment]

All fields are optional, although the operand or label fields may be required if certain directives or instructions are used in the operation field.

###### Label Field

The label field starts at the left of the line, with no preceding spaces. A label name is a sequence of alphanumeric characters, starting with a letter. You can also use the dollar sign '$' and underline character '_' in label names. A colon may be placed directly after the label, or it can be omitted. If a colon is placed after a label, it defines that label to be the value of the location counter in the current section.

###### Operation field

The operation field contains either a machine instruction or an assembler directive. You must write these in either all upper-case or all lower-case—mixed case is not allowed. The operation field must not start at the left of the line; at least one space must precede it if there is no label field. At least one space must separate the label field and the operation field.

###### Operand field

The contents of the operand depend upon the instruction or directive in the operation field. Different instructions and directives have different operand field formats. Please refer to the specific section for details of the operand field.

###### Comment field

The comment field is optional, and contains information that is not essential to the assembler, but is useful for documentation. The comment field must be separated from the previous fields by at least one space.