Java a thousand questions about the basic concepts of _01. (016) what is the difference between a _32 bit and a 64 bit computer?

Label: 32 bit computer64 bit computer64 bit instruction setX8664 explain32 bit, 64 bit difference
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What's the difference between 32 and 64 bit computers? 1?

The 32 and 64 bit computers we usually refer to are computersCPU digit. Of course, there were 8 and 16 CPU very early, in order toIntel's 80x86 seriesFor example, 8, 8080, 16, 8088, 8086, 80186, 80286, while the 32 bit of CPU first started in 80386, and the 64 bit is familiar to everyoneEM64T Technologyas well asAMD's x86-64. Of course, there is a big difference between different vendors and CPU within the same number of digits, but their core is the same:CPU processing capacity is 64 bits.

This figure refers to CPU's.Universal register(GPRs, General-Purpose, Registers) a register can be simply understood as a space where instructions, data, and addresses can be temporarily stored, and the results of the CPU operation are temporarily placed hereInstruction set and addressing capability.

Generally speaking, compared to the 32 bit CPU, the most obvious change of the 64 bit CPU isregisterandInstruction pointerUpgrade to 64 bits,Memory addressing capabilityUp to 64, and there are other changes, for exampleAn increase of 864 bit general purpose register. Higher numbers of CPU can be carried outA wider range of integer operationsAt the same timeSupport greater memory. As follows:

  • From an arithmetic point of view, a 32 bit processor can only handle 32 bits at a time, that is, 4 bytes of data, while the 64 bit processor can handle it at one time64That is,8 bytes of data.

  • From memory, the traditional 32 bit processor has the largest address spaceLess than 4G(theoretically, there are 2^32 physical addresses), which creates bottlenecks in efficiency. The 64 bit processor can theoretically reach almost17 million TB(2^64, big to surprise).

2, CPU bit size impact?

A simple example illustrates the impact of the CPU bit number. For 16 bit CPU, the instruction set can only operate16bit data and 16bit address. Different CPU registers and instruction sets are different and should be treated differently hereEight thousand and eighty-sixTo illustrate.

Put the 16bit data in the register

Such as:

MOVAX,One thousand two hundred and thirty-fourHTo send data to the register AX 1234H
MOVAH,Fifty-sixHThe data AX is passed into the high 8 bit register AH of the register 56H
MOVAL,Seventy-eightHTo transmit data to the low bit register AL in register AX,, 78H

Here's the point, the first sentence, we're goingAX registerThe number of 16bit stored in an accumulator register (1234H), but it is actually AXAH, AL two registersTherefore, these two 8 bit registers can be directly operated by AH and AL.
If we want to store a number in excess of 16bit in a register, it is not possible to do so under 16 bit CPU. If you want to deal with the number of 16bit, you can onlyWith other registersSegment processing.

Gets the data in the 16bit memory address

Such as:

MOVBX,One thousandH
MOVDS, BXTo 1000H into the DS section register, because 8086 does not support the direct data to the section register, therefore can only use other registers to pass the value.
MOV[AX.One thousand two hundred and thirty-fourH]The value in the memory address 1000H:1234H is read into the AX register

Here's one point to illustrate, 8086 physical address supportPass 20 at a timeThe address, however, is due to the 16 bit CPU instruction setOnly support 16bitThe maximum address space is 2^16 (64K). In order to be able to support 2^20 addresses (1M), it needs to be divided intoSegment addressandOffset addressForms of expression, such as1000H:1234H.

Understand CPU physical address formation see here: [CPU physical memory address how to form][2]

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