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Manufacturer's data sheets: Texas Instruments (and 74182 look-ahead carry generator) Signetics; Philips; Fairchild. Explanation of how the chip works. Inside the vintage 74181 ALU chip: how it works and why it's so strange; Inside the 74181 ALU chip: die photos and reverse engineering showing its floorplan and transistor layout of some of its gates
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]
The 74181 ALU is the large IC center-right. As a demonstration of the power of their Micromatrix gate array technology, in 1968 Fairchild prototyped the 4711, a single-chip 4-bit ALU. [ 10 ] [ 21 ] The design was never intended for mass production and was quite expensive to produce.
4-bit arithmetic logic unit/function generator, generate and propagate outputs 20 SN74LS381A: 74x382 1 4-bit arithmetic logic unit/function generator, ripple carry and overflow outputs 20 SN74LS382: 74x383 1 8-bit register open-collector 20 SN74S383: 74x384 1 8-bit by 1-bit two's complement multipliers 16 SN74LS384: 74x385 4 quad serial adder ...
Applications such as Pinball take advantage of this to accelerate performance. The Alto has a bit-slice arithmetic logic unit (ALU) based on the Texas Instruments 74181 chip, a ROM control store with a writable control store extension and has 128 (expandable to 512) KB of main memory organized in 16-bit words.
Some models of the DEC PDP-series 'minis' used the 74181 ALU as the main computing element in the CPU. Other examples were the Data General Nova series and Hewlett-Packard 21MX, 1000, and 3000 series. In 1965, typical quantity-one pricing for the SN5400 (military grade, in ceramic welded flat-pack) was around 22 USD. [19]
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.
Front page of a floppy disk controller data sheet (1979) A datasheet, data sheet, or spec sheet is a document that summarizes the performance and other characteristics of a product, machine, component (e.g., an electronic component), material, subsystem (e.g., a power supply), or software in sufficient detail that allows a buyer to understand what the product is and a design engineer to ...