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bss Section

   The bss section is used for local common variable storage.  You may
allocate address space in the bss section, but you may not dictate data
to load into it before your program executes.  When your program starts
running, all the contents of the bss section are zeroed bytes.

   Addresses in the bss section are allocated with special directives;
you may not assemble anything directly into the bss section.  Hence
there are no bss subsections. See `.comm': Comm, see `.lcomm': Lcomm..