Example using .comm pseudo-op with td storage-mapping class

The source for the C main program td2.c

1. The following is the source for the C main program td2.c:

   
   /* This C module named td2.c   */
   extern long   t_data;
   extern  void mod_s();
   main()
   {
           t_data = 1234; 
            mod_s();
            printf("t_data is %d\n", t_data);
   }
   

2. The following is the assembler source for module mod2.s:

   
           .file "mod2.s"
           .csect .mod_s[PR]
           .globl .mod_s[PR]
           .set    RTOC, 2
           l   5, t_data[TD](RTOC)  # Now GPR5 contains the
                                    # t_data value 
           ai  5,5,14
           stu 5, t_data[TD](RTOC)
           br
           .toc
           .comm  t_data[TD],4  # t_data is a global symbol
   

3. The following commands assemble and compile the source programs into an executable td2:

   
   as -o mod2.o mod2.s
   cc -o td2 td2.c mod2.o
   

4. Running td2 prints the following:

   
   t_data is 1248