Search results
Results From The WOW.Com Content Network
In computing, an arithmetic logic unit (ALU) is a combinational digital circuit that performs arithmetic and bitwise operations on integer binary numbers. [ 1 ] [ 2 ] This is in contrast to a floating-point unit (FPU), which operates on floating point numbers.
The 74181 is a 4-bit slice arithmetic logic unit (ALU), implemented as a 7400 series TTL integrated circuit. Introduced by Texas Instruments in February 1970, [1] it was the first complete ALU on a single chip. [2] It was used as the arithmetic/logic core in the CPUs of many historically significant minicomputers and other devices.
Opcodes are employed in hardware devices such as arithmetic logic units (ALUs) and central processing units (CPUs) as well as in some software instruction sets. In ALUs the opcode is directly applied to circuitry via an input signal bus, whereas in CPUs, the opcode is the portion of a machine language instruction that specifies the operation to ...
An adder, or summer, [1] is a digital circuit that performs addition of numbers. In many computers and other kinds of processors, adders are used in the arithmetic logic units (ALUs).
List of arbitrary-precision arithmetic software; Arbitrary-precision arithmetic; ARITH Symposium on Computer Arithmetic; Arithmetic logic unit; Arithmetic overflow; Arithmetic underflow; Augmented assignment
Also, 12-bit central processing unit (CPU) and arithmetic logic unit (ALU) architectures are those that are based on registers, address buses, or data buses of that size. Before the widespread adoption of ASCII in the late 1960s, six-bit character codes were common and a 12-bit word, which could hold two characters, was a convenient size.
In the 1970s and 1980s, a number of research and commercial computers used bit slicing, in which the CPU's arithmetic logic unit (ALU) was built from multiple 4-bit-wide sections, each section including a chip such as an Am2901 or 74181. The Zilog Z80, although it is an 8-bit microprocessor, has a 4-bit ALU. [11] [12]
This method is mathematically correct and has the advantage that a small CPU may perform the multiplication by using the shift and add features of its arithmetic logic unit rather than a specialized circuit. The method is slow, however, as it involves many intermediate additions. These additions are time-consuming.