Microarchitectures

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Microarchitecture is defined as those elements of a CPU design which are, to first order, invisible to application programmers (ie, not part of the instruction set). Those elements which are visible comprise the architecture.

x86 μarchitectures

FIXME: add early clones (NEC V20/V30, etc), AMD, VIA, Cyrix etc...
FIXME: add variants (80188, embedded 80386's, etc)

Name Maker Date Process (min) Package ALU/data bits Addr bits Clock(s) ISA Notes
8086 Intel 1978 3.2 μm 40-pin DIP 16 20 4--10 MHz x86-16 Segmented memory
Optional 80-bit 8087 FP coprocessor
8088 Intel 1979 3.2 μm (?) 40-pin DIP

44-pin PLCC

16/8 20 5--8 MHz x86-16 Designed for use with 8-bit externals
Used in IBM PC-5150 / XT-5160 / PCjr-4860
80186 Intel 1980 2.6 μm 68-pin PLCC
68-pin PGA
100-pin PQFP
16 20 6--25 MHz 8086-2 Designed for embedded systems
(clock, PIC, DMA on-die)
80286 Intel 1982 1.5 μm 68-pin PGA
68-pin CLCC
68-pin PLCC
16 24 4--12.5 MHz 8086-2
+ PVAM
Introduced protected mode/MMU
Used in the IBM AT-5170
80386-DX Intel 1985 CHMOS III 1.5 µm
CHMOS IV 1 µm
132-pin PGA
132-pin PQFP
32 32 12--33 MHz x86-32 Introduced paging, VM86, flat memory
Optional 80287 or 80387 FP
Support for external caches
80386-SX Intel 1988 CHMOS IV 1 µm PQFP-100
PGA-88
32/16 24 16--33 MHz x86-32 Optional 80387SX (16-bit) FP
80376 Intel 1989 CHMOS IV 1 µm PQFP-100
PGA-88
32/16 24 16--20 x86-32 Protected mode only
No paging
Optional 80387SX (16-bit) FP
80386-SL Intel 1990 CHMOS IV 1 µm PQFP-132 32/16 24 20--25 MHz x86-32 Designed for mobile/low-power systems
Added System Management Mode

Instruction sets

  • x86-16: The granddaddy of 'em all
  • 8086-2: Added ENTER/LEAVE, PUSHA/POPA, INS/OUTS
  • PVAM: Added Protected Virtual Address Mode instructions (L/S*DT, etc)

Physical Packages

  • DIP (dual in-line package): 2 parallel rows of pins
  • PGA (pin grid array): Regularly-spaced pins in rectangular geometry
  • CLCC (ceramic leadless chip carrier): Regularly-spaced metallized castellations in rectangular geometry
  • PLCC (plastic lead chip carrier): Regularly-spaced J-leads in rectangular geometry, surface- or package-mounted
  • PQFP (plastic quad flat pack): Regularly-spaced side leads in rectangular geometry, designed for surface mounting

References