A report on X86 and Accumulator (computing)

The x86 architectures were based on the Intel 8086 microprocessor chip, initially released in 1978.
Walther WSR-16 mechanical calculator. The row of digit-wheels in the carriage (at the front), is the Accumulator.
Intel Core 2 Duo, an example of an x86-compatible, 64-bit multicore processor
Front panel of an IBM 701 computer with lights displaying the accumulator and other registers
AMD Athlon (early version), a technically different but fully compatible x86 implementation
Am386, released by AMD in 1991
Registers available in the x86-64 instruction set
In supercomputer clusters (as tracked by TOP 500 data and visualized on the diagram above, last updated 2013), the appearance of 64-bit extensions for the x86 architecture enabled 64-bit x86 processors by AMD and Intel (teal hatched and blue hatched, in the diagram, respectively) to replace most RISC processor architectures previously used in such systems (including PA-RISC, SPARC, Alpha, and others), and 32-bit x86 (green on the diagram), even though Intel initially tried unsuccessfully to replace x86 with a new incompatible 64-bit architecture in the Itanium processor. The main non-x86 architecture which is still used, as of 2014, in supercomputing clusters is the Power ISA used by IBM Power microprocessors (blue with diamond tiling in the diagram), with SPARC as a distant second.

The 8051 microcontroller has two, a primary accumulator and a secondary accumulator, where the second is used by instructions only when multiplying (MUL AB) or dividing (DIV AB); the former splits the 16-bit result between the two 8-bit accumulators, whereas the latter stores the quotient on the primary accumulator A and the remainder in the secondary accumulator B. As a direct descendant of the 8008, the 8080, and the 8086, the modern ubiquitous Intel x86 processors still uses the primary accumulator EAX and the secondary accumulator EDX for multiplication and division of large numbers.

- Accumulator (computing)

For example, using AL as an accumulator and adding an immediate byte value to it produces the efficient add to AL opcode of 04h, whilst using the BL register produces the generic and longer add to register opcode of 80C3h.

- X86
The x86 architectures were based on the Intel 8086 microprocessor chip, initially released in 1978.

2 related topics with Alpha

Overall

Processor register

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Quickly accessible location available to a computer's processor.

Quickly accessible location available to a computer's processor.

Modern x86 design acquired these techniques around 1995 with the releases of Pentium Pro, Cyrix 6x86, Nx586, and AMD K5.

Data registers can hold numeric data values such as integer and, in some architectures, floating-point values, as well as characters, small bit arrays and other data. In some older and low-end CPUs, a special data register, known as the accumulator, is used implicitly for many operations.

An Intel C8080A processor variant with white ceramic package, solder seal metal lid, and gold pins.

Intel 8080

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Second 8-bit microprocessor designed and manufactured by Intel.

Second 8-bit microprocessor designed and manufactured by Intel.

An Intel C8080A processor variant with white ceramic package, solder seal metal lid, and gold pins.
i8080 microarchitecture
8080 Pinout
AMD Am9080
CEMI MCY7880 (Poland)
Kvazar Kiev K580IK80 (Soviet Union)
Mitsubishi Electric M5L8080
National Semiconductor INS8080
NEC μPD8080AF
OKI MSM8080
Siemens SAB8080
Signetics MP8080
Tesla (Czechoslovak company) MHB8080
Texas Instruments TMS8080

The 8080 directly influenced the later x86 architecture.

All 8-bit operations with two operands can only be performed on the 8-bit accumulator (the A register).