as: Word
7.107 '.word EXPRESSIONS'
=========================
This directive expects zero or more EXPRESSIONS, of any section,
separated by commas.
The size of the number emitted, and its byte order, depend on what
target computer the assembly is for.
_Warning: Special Treatment to support Compilers_
Machines with a 32-bit address space, but that do less than 32-bit
addressing, require the following special treatment. If the machine of
interest to you does 32-bit addressing (or doesn't require it; 
Machine Dependencies), you can ignore this issue.
In order to assemble compiler output into something that works, 'as'
occasionally does strange things to '.word' directives. Directives of
the form '.word sym1-sym2' are often emitted by compilers as part of
jump tables. Therefore, when 'as' assembles a directive of the form
'.word sym1-sym2', and the difference between 'sym1' and 'sym2' does not
fit in 16 bits, 'as' creates a "secondary jump table", immediately
before the next label. This secondary jump table is preceded by a
short-jump to the first byte after the secondary table. This short-jump
prevents the flow of control from accidentally falling into the new
table. Inside the table is a long-jump to 'sym2'. The original '.word'
contains 'sym1' minus the address of the long-jump to 'sym2'.
If there were several occurrences of '.word sym1-sym2' before the
secondary jump table, all of them are adjusted. If there was a '.word
sym3-sym4', that also did not fit in sixteen bits, a long-jump to 'sym4'
is included in the secondary jump table, and the '.word' directives are
adjusted to contain 'sym3' minus the address of the long-jump to 'sym4';
and so on, for as many entries in the original jump table as necessary.
Info Catalog
as: Weakref
as: Pseudo Ops
as: Zero