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Texas Instruments SN74181
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, it was the first complete ALU on a single chip. It was used as the arithmetic/logic core in the CPUs of many historically significant minicomputers and other devices. The 74181 represents an evolutionary step between the CPUs of the 1960s, which were constructed using discrete logic gates, and single-chip microprocessors of the 1970s. Although no longer used in commercial products, the 74181 later was used in hands-on computer architecture courses and is still referenced in textbooks and technical papers. Specifications The 74181 is a 7400 series medium-scale integration (MSI) TTL integrated circuit, containing the equivalent of 75 logic gates and most commonly packaged as a 24-pin DIP. The 4-bit wide ALU can perform all the traditional add / subtract / decrement operations with or without carry, as well as AND / NA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bitwise XOR
In computer programming, a bitwise operation operates on a bit string, a bit array or a binary numeral (considered as a bit string) at the level of its individual bits. It is a fast and simple action, basic to the higher-level arithmetic operations and directly supported by the processor. Most bitwise operations are presented as two-operand instructions where the result replaces one of the input operands. On simple low-cost processors, typically, bitwise operations are substantially faster than division, several times faster than multiplication, and sometimes significantly faster than addition. While modern processors usually perform addition and multiplication just as fast as bitwise operations due to their longer instruction pipelines and other architectural design choices, bitwise operations do commonly use less power because of the reduced use of resources. Bitwise operators In the explanations below, any indication of a bit's position is counted from the right (least si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
16-bit Computing
16-bit microcomputers are microcomputers that use 16-bit microprocessors. A 16-bit register can store 216 different values. The range of integer values that can be stored in 16 bits depends on the integer representation used. With the two most common representations, the range is 0 through 65,535 (216 − 1) for representation as an ( unsigned) binary number, and −32,768 (−1 × 215) through 32,767 (215 − 1) for representation as two's complement. Since 216 is 65,536, a processor with 16-bit memory addresses can directly access 64 KB (65,536 bytes) of byte-addressable memory. If a system uses segmentation with 16-bit segment offsets, more can be accessed. As of 2025, 16-bit microcontrollers cost well under a dollar (similar to close in price legacy 8-bit); the cheapest 16-bit microcontrollers cost less than other types including any 8-bit (and are more powerful, and easier to program generally), making 8-bit legacy microcontrollers not worth it for new applications ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data General Nova
The Nova is a series of 16-bit computing, 16-bit minicomputers released by the American company Data General. The Nova family was very popular in the 1970s and ultimately sold tens of thousands of units. The first model, known simply as "Nova", was released in 1969. The Nova was packaged into a single Rack unit, 3U rack-mount case and had enough computing power to handle most simple tasks. The Nova became popular in science laboratories around the world. It was followed the next year by the SuperNOVA, which ran roughly four times as fast, making it the fastest mini for several years. Introduced during a period of rapid progress in integrated circuit (or "microchip") design, the line went through several upgrades over the next five years, introducing the 800 and 1200, the Nova 2, Nova 3, and ultimately the Nova 4. A single-chip implementation was also introduced as the microNOVA in 1977, but did not see widespread use as the market moved to new microprocessor designs. Fairchil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CPU Design
Processor design is a subfield of computer science and computer engineering (fabrication) that deals with creating a processor (computing), processor, a key component of computer hardware. The design process involves choosing an instruction set and a certain execution paradigm (e.g. Very long instruction word, VLIW or Reduced instruction set computing, RISC) and results in a microarchitecture, which might be described in e.g. VHDL or Verilog. For microprocessor design, this description is then manufactured employing some of the various semiconductor device fabrication processes, resulting in a Die (integrated circuit), die which is bonded onto a chip carrier. This chip carrier is then soldered onto, or inserted into a CPU socket, socket on, a printed circuit board (PCB). The mode of operation of any processor is the execution of lists of instructions. Instructions typically include those to compute or manipulate data values using Processor register, registers, change or retrieve va ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Organization
In electronics, computer science and computer engineering, microarchitecture, also called computer organization and sometimes abbreviated as μarch or uarch, is the way a given instruction set architecture (ISA) is implemented in a particular processor. A given ISA may be implemented with different microarchitectures; implementations may vary due to different goals of a given design or due to shifts in technology. Computer architecture is the combination of microarchitecture and instruction set architecture. Relation to instruction set architecture The ISA is roughly the same as the programming model of a processor as seen by an assembly language programmer or compiler writer. The ISA includes the instructions, execution model, processor registers, address and data formats among other things. The microarchitecture includes the constituent parts of the processor and how these interconnect and interoperate to implement the ISA. The microarchitecture of a machine is usua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Printed Circuit Board
A printed circuit board (PCB), also called printed wiring board (PWB), is a Lamination, laminated sandwich structure of electrical conduction, conductive and Insulator (electricity), insulating layers, each with a pattern of traces, planes and other features (similar to wires on a flat surface) Chemical milling, etched from one or more sheet layers of copper laminated onto or between sheet layers of a non-conductive substrate. PCBs are used to connect or Electrical wiring, "wire" Electronic component, components to one another in an electronic circuit. Electrical components may be fixed to conductive pads on the outer layers, generally by soldering, which both electrically connects and mechanically fastens the components to the board. Another manufacturing process adds Via (electronics), vias, metal-lined drilled holes that enable electrical interconnections between conductive layers, to boards with more than a single side. Printed circuit boards are used in nearly all e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bitwise Operation
In computer programming, a bitwise operation operates on a bit string, a bit array or a binary numeral (considered as a bit string) at the level of its individual bits. It is a fast and simple action, basic to the higher-level arithmetic operations and directly supported by the central processing unit, processor. Most bitwise operations are presented as two-operand instructions where the result replaces one of the input operands. On simple low-cost processors, typically, bitwise operations are substantially faster than division, several times faster than multiplication, and sometimes significantly faster than addition. While modern processors usually perform addition and multiplication just as fast as bitwise operations due to their longer instruction pipelines and other computer architecture, architectural design choices, bitwise operations do commonly use less power because of the reduced use of resources. Bitwise operators In the explanations below, any indication of a bit's p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carry-lookahead Adder
A carry-lookahead adder (CLA) or fast adder is a type of Adder (electronics), electronics adder used in digital logic. A carry-lookahead adder improves speed by reducing the amount of time required to determine carry bits. It can be contrasted with the simpler, but usually slower, ripple-carry adder (RCA), for which the carry bit is calculated alongside the sum bit, and each stage must wait until the previous carry bit has been calculated to begin calculating its own sum bit and carry bit. The carry-lookahead adder calculates one or more carry bits before the sum, which reduces the wait time to calculate the result of the larger-value bits of the adder. Already in the mid-1800s, Charles Babbage recognized the performance penalty imposed by the ripple-carry used in his Difference engine, Difference Engine, and subsequently designed mechanisms for ''anticipating carriage'' for his never-built Analytical Engine. Konrad Zuse is thought to have implemented the first carry-lookahead ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Logic Level
In digital circuits, a logic level is one of a finite number of states that a digital signal can inhabit. Logic levels are usually represented by the voltage difference between the signal and ground, although other standards exist. The range of voltage levels that represent each state depends on the logic family being used. A '' logic-level shifter'' can be used to allow compatibility between different circuits. 2-level logic In binary logic the two levels are logical high and logical low, which generally correspond to binary numbers 1 and 0 respectively or truth values ''true'' and ''false'' respectively. Signals with one of these two levels can be used in Boolean algebra for digital circuit design or analysis. Active state The use of either the higher or the lower voltage level to represent either logic state is arbitrary. The two options are active high (''positive logic'') and active low (''negative logic''). Active-high and active-low states can be mixed at will: for ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
64-bit Computing
In computer architecture, 64-bit integers, memory addresses, or other data units are those that are 64 bits wide. Also, 64-bit central processing units (CPU) and arithmetic logic units (ALU) are those that are based on processor registers, address buses, or data buses of that size. A computer that uses such a processor is a 64-bit computer. From the software perspective, 64-bit computing means the use of machine code with 64-bit virtual memory addresses. However, not all 64-bit instruction sets support full 64-bit virtual memory addresses; x86-64 and AArch64, for example, support only 48 bits of virtual address, with the remaining 16 bits of the virtual address required to be all zeros (000...) or all ones (111...), and several 64-bit instruction sets support fewer than 64 bits of physical memory address. The term ''64-bit'' also describes a generation of computers in which 64-bit processors are the norm. 64 bits is a Word (computer architecture), word size that defines ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
