Assembler Directives - SECTION

SECTION - This directive causes the program counter to be restored to the address following the last location allocated in the indicated section (or to zero if used for the first time). The ORG directive may be used within a section, at any time, to set the current program location. The assembler does not check for overlapping sections. The section directive provides a convenient way of separating code from data within a program.

Usage:
[label] SECTION [<number>]

<number> must be in the range 0..15.  No section numbers are reserved in any way. By default, the assembler will begin with section 0. Labels may be used for section numbers. If no section number is specified then a label is required and will be set to the value of the current section (0..15).
 

CODE   EQU    0
DATA   EQU    1

       SECTION DATA
       ORG     $2000
msg1   DC.B    'Hello World',$d,$a,0
       SECTION CODE
       ORG     $1000
       <code>
       SECTION DATA
msg2   DC.B    'EASy68K Rules!',$d,$a,0

Macros may be written to change sections and restore the previous section as shown in the following example:

DATA    EQU     0
CODE    EQU     1

MAC1    MACRO
SECT\@  SECTION
        SECTION DATA
        DC.B    'Hello World.'
        SECTION SECT\@
        ENDM

It is also possible to write a macro that modifies its behavior using conditional assembly based upon the section it is in when invoked as shown in the following example:

DATA    EQU     0
CODE    EQU     1

MAC2    MACRO
SECT\@  SECTION
        IFEQ SECT\@-CODE
          NOP
        ENDC
        IFEQ SECT\@-DATA
          DC.B  'Greetings'
        ENDC
        ENDM

See Macro Assembly for more help on writing macros.