BUS, Registers, and Flags Bus A bus is a bundle of wires grouped together to serve a single-purpose. The main application of the bus is to transfer data from one device to another. The processor’s interface to the bus includes connections used to pass data, connections to represent the address with which the processor interested, and …
Buffers Rarely does a processor operate in isolation. Typically there are multiple processors supporting the operation of the main processor. These include video processors, the keyboard and mouse interface processor, and the processors providing data from hard drives and CROMs. There are also processors to control communication interfaces such as USB, Firewire, and Ethernet networks. These processors …
Processor Level and CPU Level Processor Level An image below presents the generic block diagram of a processor system. It represents the interface between the processor, memory, and I/O devices through the bus that we discussed in the section on memory interfacing in. The internals of a processor are a microcosm of the processor system shown in …
8086 Execution Unit The 8086 processor is divided into two main components: the execution unit and the bus interface unit. It is controlled by the EU control system which serves a dual purpose: it acts as the control unit and also as a portion of the instruction decoder. The EU also contains the ALU, the processor flags, and the general purpose and …
8086 Bus Interface The bus interface unit (BIU) controls the transfer of information between the processor and the external devices such as memory, I/O ports, and storage devices. Basically, it acts as the bridge between the EU and the external bus. A portion of the instruction decoder is located in the BIU. The instruction queue acts as a buffer …
8086 Assembly Language This language was presented to create a few simple programs and present how the CPU executed code. In this chapter, the assembly language of the Intel 80×86 processor family is introduced along with the typical syntax for writing 80×86 assembly language programs. This information is then used to write a sample program for the 80×86 processor. Assemblers versus Compilers For …