B. Assemblers, Compilers, Linkers, and Loaders [15]

Assemblers and compilers both translate statements in the programming language, referred to as a source-code statement, into some other format that eventually leads to a binary code that the processor can execute. The simplest form o f assembler converts a mnemonic name to the appropriate binary code, for example, the state­ ment L D A , 10 to a bit pattern 01011010. The basic assembly statement pattern is

Most assemblers supplement the above by allowing the use o f symbolic names for addresses, labels, and constants, wi th , in addition, means o f allocating storage ar­ eas and support for modularization o f the code into segments wi th control o f scope and visibili ty o f symbols. Some other assembler features are

• Absolute addressing: Assemblers o f this determine all addresses at the time o f assembly and the object-code produced can be directly loaded into memory and run. This type o f assembler is suitable for small systems but poses difficulties i f there is a need to divide the source-code into separate modules.