x86

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x86
Designer Intel, AMD
Bits 16-bit, 32-bit an 64-bit
Introduced 1978 (16-bit), 1985 (32-bit), 2003 (64-bit)
Design CISC
Teep Register-memory
Encodin Variable (1 tae 15 bytes)
Branchin Status register
Endianness Little
Page size 8086i286: None
i386, i486: 4 KB pages
P5 Pentium: addit 4 MB pages
(Legacy PAE: 4 KB→2 MB)
x86-64: addit 1 GB pages
Extensions x87, IA-32, MMX, SSE, SSE2, x86-64, SSE3, SSSE3, SSE4, SSE5, AVX
Open Pairtly. For some advanced featurs, x86 mey require license frae Intel; x86-64 mey require an addeetional license frae AMD. The 80486 processor haes been on the mercat for mair than 20 years[1] an so cannot be subject tae patent claims. The pre-586 subset o the x86 airchitectur is tharefore fully open.
Registers
General purpose
  • 16-bit: six semi-dedicatit registers, BP an SP are nae general-purpose
  • 32-bit: aicht GPRs, includin EBP an ESP
  • 64-bit: 16 GPRs, includin RBP an RSP
Floatin pynt
  • 16-bit: optional separate x87 FPU
  • 32-bit: optional separate or integratit x87 FPU, integratit SSE2 units in later processors
  • 64-bit: integratit x87 an SSE2 units

x86 is a faimily o backward compatible instruction set airchitecturs[lower-alpha 1] based on the Intel 8086 CPU an its Intel 8088 variant.

Notes[eedit | eedit soorce]

  1. Unlik the microairchitectur (an speceefic electronic an phesical implementation) uised for a speceefic microprocessor design

References[eedit | eedit soorce]

  1. Pryce, Dave (Mey 11, 1989). "80486 32-bit CPU breaks new ground in chip density and operating performance. (Intel Corp.) (product announcement) EDN" (Press release).