Zilog Z8F0130 - Manual (Page 336)

Using the Macro Assembler UM013037-1212
312
Zilog Developer Studio II – Z8 Encore!
User Manual
XREF
Specifies that a list of labels in the operand field are defined in another module. The refer-
ence is resolved by the linker. The labels must not be defined in the current module. This
directive optionally specifies the address space in which the label resides.
Synonyms
.extern , EXTERN , EXTERNAL , .ref
Syntax
<xref_directive> => XREF <ident_space_list>

<ident_space_list> => <ident_space>

=> <ident_space_list>, <ident_space>

<ident_space> => <ident> [:<space>]
Examples
XREF label

XREF label1,label2,label3

XREF label:ROM
Structures and Unions in Assembly Code
The assembler provides a set of directives to group data elements together, similar to high-
level programming language constructs like a C structure or a Pascal record. These direc-
tives allow you to declare a structure or union type consisting of various elements, assign
labels to be of previously declared structure or union type, and provide multiple ways to
access elements at an offset from such labels.
The assembler directives associated with structure and union support are listed in the fol-
lowing table:
The structure and union directives are described in the following sections:
Assembler Directive Description
.STRUCT Group data elements in a structure type
.ENDSTRUCT Denotes end of structure or union type
.UNION Group data elements in a union type
.TAG Associate label with a structure or union type
.WITH A section in which the specified label or structure tag is
implicit
.ENDWITH Denotes end of with section