Comment line, Label field, Instruction – Zilog ZUSBOPTS User Manual
Page 245: Directive
UM017105-0511
Source Language Structure
Zilog Developer Studio II – ZNEO™
User Manual
217
Comment Line
A semicolon (;) terminates the scanning action of the assembler. Any text following the
semicolon is treated as a comment. A semicolon that appears as the first character causes
the entire line to be treated as comment.
Label Field
A label must meet at least one of the following conditions:
•
It must be followed by a colon.
•
It must start at the beginning of the line, with no preceding white space (start in col-
umn 1). When an instruction is in the first column, it is treated as an instruction and
not a label.
The first character of a label can be a letter, an underscore ( _ ) , a dollar sign ($), a question
mark (?), a period (.) or a pound sign (#). Following characters can include letters, digits,
underscores, dollar signs ($), question marks (?), periods (.), or pound signs (#). The label
can be followed by a colon (:) that completes the label definition. A label can only be
defined once. The maximum label length is 129 characters. See the
page 250 for more information.
Labels that can be interpreted as hexadecimal numbers are not allowed. For example,
ADH:
ABEFH:
cannot be used as labels.
For more information, see the
Instruction
An instruction contains one valid assembler instruction that consists of a mnemonic and its
arguments. When an instruction is in the first column, it is treated as an instruction and not
a label. Use commas to separate the operands. Use a semicolon or carriage return to termi-
nate the instruction. For more information about ZNEO CPU instructions, see the Instruc-
tion Set Description section of
.
Directive
A directive tells the assembler to perform a specified task. Use a semicolon or carriage
return to terminate the directive. Use spaces or tabs to separate the directive from its oper-
ands. See the
section on page 226 for more information.