Zilog Z8F0130 - Manual (Page 339)

UM013037-1212 Structures and Unions in Assembly Code
Zilog Developer Studio II – Z8 Encore!
User Manual
315
The .TAG directive to assign a label to have a structure type has the following form:
[tname] .TAG stag ; Apply stag to tname
[tname] DS ssize ; Allocate space for tname
Once applied to label tname, the individual structure elements are applied to tname to pro-
duce the desired offsets using tname as the structure base. For example, the label
tname.name_2 is created and assigned the value tname + stag.name_2 . If there are
any alignment requirements with the structure, the .TAG directive attaches the required
alignment to the label. The optional count on the .TAG directive is meaningful only inside
a structure definition and implies an array of the .TAG structure.
Keeping the space allocation separate allows you to place the .TAG declarations that assign
structure to a label in the header file in a similar fashion to the .STRUCT and XREF direc-
tives. You can then include the header file in multiple source files wherever the label is
used. Make sure to perform the space allocation for the label in only one source file.
Examples of the .TAG directive are as follows:
DATE .STRUCT

MONTH DS 1

DAYDS 1

YEAR DS 2

DSIZE .ENDSTRUCT DATE
NAMELEN EQU 30
EMPLOYEE .STRUCT

NAME DS NAMELEN

SOCIAL DS 10

START .TAG DATE

SALARY DS 1

ESIZE .ENDSTRUCT EMPLOYEE
NEWYEARS .TAG DATE

NEWYEARS DS DSIZE
The .TAG directive in the last example above creates the symbols NEWYEARS.MONTH ,
NEWYEARS.DAY , and NEWYEARS.YEAR . The space for NEWYEARS is allocated by the DS
directive.
Note: