MACHINE LANGUAGE AND ASSEMBLY LANGUAGE

Although there are many different machine languages, many concepts are common to all of these languages. Some of the common ideas are binary arithmetic, index registers, memory addresses, floating-point arithmetic, control operations, and logical operations. This chapter presents these ideas by discussing IBM 7090. These ideas can be easily extended to a variety of other machines. The IBM 7090 has a simple structure and most of what is relevant to the description of any other large computer. The chapter focuses on the central part of the computer, namely, the central processing unit (CPU) and the memory. The memory contains numbers and instructions. Information to be used by a computer can be stored on a number of different devices. Magnetic tape, magnetic disks, or magnetic cores are some of the more common memories used in computers. The contents of the memory can be represented in the binary notation or they can be represented in the equivalent octal notation. The memory is divided into words. A word consists of 36 bits in the IBM 7090.