9.3 Absolute Lister Example

This example uses three source files. The files module1.asm and module2.asm both include the file globals.def.

module1.asm

        .text
        .bss    dflag, 1
        .bss    array, 100
dflag_a .word   dflag
array_a .word   array
offst_a .word   offst
        .copy   globals.def
        LDR     r4, array_a     
        LDR     r5, offst_a
        LDR     r3, dflag_a
        LDR     r0, [r4, r5]
        STR     r0, [r3]

module2.asm

        .text
        .bss    offst, 1
offst_a .word   offst
        .copy   globals.def
        LDR     r4, offst_a
        STR     r0, [r4]

globals.def

        .global array
        .global offst
        .global dflag

The following steps create absolute listings for the files module1.asm and module2.asm:

Step 1:	First, assemble module1.asm and module2.asm: `armcl module1 armcl module2` This creates two object files called module1.obj and module2.obj.
Step 2:	Next, link module1.obj and module2.obj using the following linker command file, called bttest.cmd:

            --output_file=bttest.out
            --map_file=bttest.map
            module1.obj
            module2.obj
            MEMORY
            {
               P_MEM :  org = 0x00000000  len = 0x00001000
               D_MEM :  org = 0x00001000  len = 0x00001000
            }
            SECTIONS
            { 
               .data:  >D_MEM
               .text:  >P_MEM
               .bss:   >D_MEM
            }

Invoke the linker: armcl --run_linker bttest.cmd

This command creates an executable object file called bttest.out; use this file as input for the absolute lister.

Step 3:

Now, invoke the absolute lister:

armabs bttest.out

This command creates two files called module1.abs and module2.abs:

module1.abs:

                       .nolist
             array     .setsym     000001001h
             dflag     .setsym     000001000h
             offst     .setsym     000001068h
             .data     .setsym     000001000h
             edata     .setsym     000001000h
             .text     .setsym     000000000h
             etext     .setsym     00000002ch
             .bss      .setsym     000001000h
             end       .setsym     00000106ch
                       .setsect    ".text",000000000h
                       .setsect    ".data",000001000h
                       .setsect    ".bss",000001000h
                       .list
                       .text
                       .copy       "module1.asm"

module2.abs:

                       .nolist
             array     .setsym     000001001h
             dflag     .setsym     000001000h
             offst     .setsym     000001068h
             .data     .setsym     000001000h
             edata     .setsym     000001000h
             .text     .setsym     000000000h
             etext     .setsym     00000002ch
             .bss      .setsym     000001000h
             end       .setsym     00000106ch
                       .setsect    ".text",000000020h
                       .setsect    ".data",000001000h
                       .setsect    ".bss",000001068h
                       .list
                       .text
                       .copy       "module2.asm"

These files contain the following information that the assembler needs for Step 4:

They contain .setsym directives, which equate values to global symbols. Both files contain global equates for the symbol dflag. The symbol dflag was defined in the file globals.def, which was included in module1.asm and module2.asm.
They contain .setsect directives, which define the absolute addresses for sections.
They contain .copy directives, which defines the assembly language source file to include.

The .setsym and .setsect directives are useful only for creating absolute listings, not normal assembly.

Step 4:

Finally, assemble the .abs files created by the absolute lister (remember that you must use the --absolute_listing option when you invoke the assembler):

armcl --absolute_listing module1.abs
                
                
armcl --absolute_listing module2.abs

This command sequence creates two listing files called module1.lst and module2.lst; no object code is produced. These listing files are similar to normal listing files; however, the addresses shown are absolute addresses.

The absolute listing files created are module1.lst (see Example 1 ) and module2.lst (see Example 2).