Search results
Results From The WOW.Com Content Network
A complex instruction set computer (CISC / ˈ s ɪ s k /) is a computer architecture in which single instructions can execute several low-level operations (such as a load from memory, an arithmetic operation, and a memory store) or are capable of multi-step operations or addressing modes within single instructions.
An instruction set architecture (ISA) is an abstract model of a computer, also referred to as computer architecture.A realization of an ISA is called an implementation.An ISA permits multiple implementations that may vary in performance, physical size, and monetary cost (among other things); because the ISA serves as the interface between software and hardware.
The first was the CISC (Complex Instruction Set Computer), which had many different instructions. In the 1970s, however, places like IBM did research and found that many instructions in the set could be eliminated. The result was the RISC (Reduced Instruction Set Computer), an architecture that uses a smaller set of instructions.
The PDP-11 architecture [1] is a 16-bit CISC instruction set architecture (ISA) developed by Digital Equipment Corporation (DEC). It is implemented by central processing units (CPUs) and microprocessors used in PDP-11 minicomputers. It was in wide use during the 1970s, but was eventually overshadowed by the more powerful VAX architecture in the ...
z/Architecture, initially and briefly called ESA Modal Extensions (ESAME), is IBM's 64-bit complex instruction set computer (CISC) instruction set architecture, implemented by its mainframe computers. IBM introduced its first z/Architecture-based system, the z900, in late 2000. [1]
VAX has been perceived as the quintessential CISC ISA, [3] with its very large number of assembly language programmer-friendly addressing modes and machine instructions, highly orthogonal instruction set architecture, and instructions for complex operations such as queue insertion or deletion, number formatting, and polynomial evaluation. [4]
Very long instruction word (VLIW) refers to instruction set architectures that are designed to exploit instruction-level parallelism (ILP). A VLIW processor allows programs to explicitly specify instructions to execute in parallel, whereas conventional central processing units (CPUs) mostly allow programs to specify instructions to execute in sequence only.
Selection of an instruction set architecture affects , whereas is largely determined by the manufacturing technology. Classic Complex Instruction Set Computer (CISC) ISAs optimized I n s t r u c t i o n s P r o g r a m {\displaystyle \mathrm {\tfrac {Instructions}{Program}} } by providing a larger set of more complex CPU instructions .