Echelon Neuron - Manual (Page 24)

Displacements
A displacement is a relative address value. A displacement can be interpreted as
a signed or unsigned number, depending on the instruction with which the
displacement appears.
To compute the absolute address value, add the displacement (using either
signed or unsigned arithmetic, as appropriate) to the absolute address of the
instruction that contains the displacement.
Address Expressions
An address expression is an expression that specifies an address, and can be one
of the following types of expression: a literal constant, a symbol with an optional
offset expression, or the * special operator with an optional offset expression.
The optional offset expression is a general expression with a prefixed + (addition)
or - (subtraction) operator.
An address expression can consist of a mixture of locally defined and imported
symbols from the same or from multiple segments. However, symbols from other
segments must be exported, even if they are not used by other modules.
Comments
A comment is part of an assembly source line that provides useful information to
the code developer. The Neuron Assembler ignores comments. A comment starts
with a semicolon character (;) and ends with a newline or carriage-return
character.
Recommendation: Use comments to document changes to the data and return
stacks. See Documenting Changes to the Stack for a recommended method of
documenting stack changes.
Assembler Directives
An assembler directive provides information to the Neuron Assembler to control
or affect the processing of the remainder of the assembly file.
The directives have syntax analogous to the assembly instructions. Most
directives require arguments, which are similar to the operands of the assembly
instructions.
See Chapter 7, Neuron Assembler Directives, for more information about the
Neuron Assembler directives.
Interfacing with Neuron C Programs
Typically, you use Neuron assembly language to create utilities that can be used
with an application that is written in Neuron C. The Neuron C program code
might call functions defined in Neuron assembly, or a Neuron assembly function
might call a Neuron C function or program.
See Chapter 4, Interfacing with a Neuron C Application, for more information
about how Neuron assembly language functions and Neuron C program interact.
14 Introduction