CS 121 Lecture Notes - Lecture 10: Binary Number, Program Counter, Register File
27 Jul 2020
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Document Summary
The alu is the calculation engine of the cpu. The set of operations that the alu is capable of, and the speed with which it can perform them, greatly influences the final performance of the microprocessor. Therefore, the design of the alu is crucial in the design of a processor and deserves special attention. Figure 3 shows the general layout of an alu. The $ and % terminals are actually input ports (composed of several lines, forming one binary word each). The data entered in $ and % are the operands with which the alu will perform the following operation. This operation is selected through the lines of the port named 23(5$&, 1. Each possible operation to be made has a binary number associated with it, which is the one introduced in that port. When the alu performs the selected mathematical or logical operation, it returns the result using the & port.
