Microprocessor size

Question

I read that the microprocessor consists of several components, each of which has the same / different "sizes". But what really confuses me is that it defines the specified microprocessor size as 16-bit, 32-bit or 64-bit ...

It:

• ALU capacity?
• data bus size?
• address bus size?
• “least common denominator” of the above?
• or any other factor that I still don’t know about?

Answer 1

Typically, the processor bit size is the size of its general purpose registers. this often matches the size of the memory bus and possibly the address bus, but not necessarily.

, Intel 386 386SX (http://en.wikipedia.org/wiki/Intel_80386#The_i386SX_variant), 386 32- , 16- . , , - 32- , 16- .

Answer 2

, . , "" ( ) . "" DEC PDP-8/E - - 12 12- , PDP-11 16 , 16 - . IBM 370 VAX 32- 32- .

80386, . 8086, (PM) 80286 PM 80386. 64- , AMD64 x86-64, , 64- . ? , . Windows NT 2000, Windows XP-32, Vista-32 7-32 32-. "64" 64 .

. x86- + i/o. , /, .. 8086/8088 A0-A15 D0-D15/A0-A7 D0-D7, A16-A19/A8-A19 . 80286 , 80186/80188. 80286 24 16 . 80386 80486 32 . 80386SX , 80286.

. , , RAM. , 64- , Pentium Pentium MMX, 32- 32 , 64 .

36, 64 . 32-.

, . -. , , 128 .

64- 64 , 16 , . 128 , , 37 .

, . 25 (80386 ) .

C int . AMD64 , 64- ints : 32- ints . C AMD64 64 .

Answer 3

This usually refers to the number of memory bytes (2 ^ n) that are addressed to the CPU. Usually this is the same as the data bus, but the hardware can perform multiple access to extract this amount, so it is not 100% guaranteed. Sometimes this also matches the size of the CPU registers, but it may also be different.