As the assembler reads the second line of this program, an undefi ned label AGAIN is encoun-
tered. e assembler has no knowledge of it as yet, but the value of the symbol AGAIN is
needed before it can be defi ned. is is also called the future symbol problem or the problem
of unresolved references. is problem is solved in various ways depending on the type of the
assembler.
2.1.4|Two Pass Assemblers
ere are many types of assemblers – one pass, two pass and multi pass assemblers. Each pass
optimizes the assembly process. Two pass assemblers are the commonest, so let us discuss those.
A pass implies ...
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