Using modules

Large projects can be hard to handle when using the single source file approach. The list of includes can get very long if you have several hundred files. To answer this concern RadASM is capable of separately assembling multiple asm source files to individual object files and bringing them together in the link process. The last edit time of the source file is checked against it's object file and the source is only compiled if necessary, this reduces compile time as only those modules that need to be recompiled will be.

You must enable Assemble Modules in in order to activate module support for a particular project. To add a module to a project requires two steps. First you must select Add New from the and add a new module. You will be prompted to create an asm source file. Once you are finished editing the source file you select Assemble Modules form the to assemble it. For the linker to see your file you must add it to the list of linked files by adding it's object file to the project using Add Existing and selecting the newly created module.

As an alternative to adding the object files to your project you can also change the link command to the following in order to have all object files included in the link, note that this will not work with linkers that do not permit wildcards in file names, for those you will have to add the object file manually. 

For masm
5,OT,$B\LINK.EXE /SUBSYSTEM:WINDOWS /RELEASE /VERSION:4.0 /LIBPATH:"$L" *.obj,4

The required structure for a module varies from assembler to assembler but generally it must not have an entry point and you must declare any commonly used variables as public. This is an example of a module file written for MASM 

.586
.mmx
.model flat,stdcall
option casemap:none
;#########################################################################
; Include files
include \masm32\include\windows.inc
include \masm32\include\user32.inc
include \masm32\include\kernel32.inc
;#########################################################################
; Libraries
includelib \masm32\lib\user32.lib
includelib \masm32\lib\kernel32.lib
PUBLIC datalabel ; exported to other modules
EXTERN extlabel:DWORD ; imported from another module
.data?
datalabel dd ?
.code
; note no entry point
end