Register Transfer Language
A digital system Is an interconnection of digital hardware module. that accompalish a specific Wormation-proceaslna taslc. Digital systems vary in size and complexi.ty interacting digital &om a few integrated circuits to a complex of interconnected and computers. Digital system design invariably Uses a modular approach. The modules are constructed &om such digital components as ules registet&, are in decoders, terconnected arithmetic with common elements data and control paths , and control logic. The to fonn various moda digital computer system.
Digital modules are best defined by the registet& they contain and the operations executed that are performed on the data stored in them. The operations on data stored in reglstet& are called miaooperations. A mlaooperation is an elementaxy operation perfonned on the infonNtion stored in one or infonNition more registers. The result of the operation may replace the previous binary of a register or may be tnmsferred to another register. Examples of ponents mlcrooperations introduced are in Chap. shift, count, 2 are registet& clear, and load. that implement Some of microoperations. the digital comFor example, a counter with parallel load is capable of performing the moperations increment and load. A bidirectional shift register is capable of performing the shift right and shift left microoperations.
The internal hardware organization of a digital computer is best defined by specifying:
1. The set of registers it contains and their function.
2. The sequence of microoperations performed on the binary information stored in the registers.
3. The control that initiates the sequence of microoperations.
It is possible to specify the sequence of microoperations in a computer by explaining every operation in words, but this procedure usually involves a lengthy descriptive explanation. It is more convenient to adopt a suitable symbology to describe the sequence of transfers between registers and the various arithmetic and logic microoperations associated with the transfers. The use of symbols instead of a narrative explanation provides an organized and concise manner for listing the microoperation sequences in registers and the control functions that initiate them.