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instruction set, which are used for instructing the system how we want the
program to be assembled inside the computer's memory. For example, there may
be pseudo-instructions for telling the system things like:
DATA AT 0000 ASIDE
ASIDE AN ADDRESS FOR FRST
AN ADDRESS FOR SCN AT 1000 SET ASIDE D
AN ADDRESS FOR ANS
R With this feature, a programmer need not keep track of the storage locations of the
data and instructions while writing an assembly language program. That is, he/she
need not even tell the computer where to place each data item and where to place
each instruction of a program.
A language, which allows instructions and storage locations to be represented by
letters and symbols instead of numbers, is called an assembly language or
symbolic language. A program written in an assembly language is called an
assembly language program or a symbolic program.
During the discussion of machine language, we saw that a computer can directly
execute only machine language programs that use numbers for representing
instructions and storage locations. Hence an assembly language program must be
converted (translated) into its equivalent machine language program before it can
be executed on the computer. This translation is done with the help of a translator
program known as an assembler. The assembler of a computer system is a system
software, supplied by the computer manufacturer that translates an assembly
language program into an equivalent machine language program of the computer.
It is so called because in addition to translating an assembly language program
into its equivalent machine language program, it also, "assembles" the machine
language program in the main memory of the computer and makes it ready for
The process of translating an assembly language program into its equivalent
machine language program with the use of an assembler is illustrated in Figure
12.2. As shown in the figure, the input to the assembler is the assembly language
program (often referred to as a source program) and its output is the mac...
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- Spring '14