Accessing Labels From Other Modules

Accessing Labels From Other Modules

Labels that are defined in one module for use in other modules must be exported using the GLOBAL directive. Labels must be defined before they are declared GLOBAL. Modules that use these labels must use the EXTERN directive to declare the existence of these labels. An example of using the GLOBAL and EXTERN directives is shown below.

Relocatable Code, Defining Module

UDATA

InputGain RES 1

OutputGain RES 1

GLOBAL InputGain, OutputGain

CODE

Filter

GLOBAL Filter

: ; Filter code

Relocatable Code, Referencing Module

EXTERN InputGain, OutputGain, Filter

UDATA

Reading RES 1

CODE

...

MOVLW GAIN1

MOVWF InputGain

MOVLW GAIN2

MOVWF OutputGain

MOVF Reading,W

CALL Filter