Why are there so many processor architectures: x86, x64, x87, etc. ??

Question

Is the main other simple set of commands or something more important?

Answer 1

x86 is actually an acronym for the 8086 series of processors. Yes, this is a specific set of instructions; and usually indicates that it is a 32-bit system (bus size). x64 usually has the same instruction set, but represents a 64-bit system (bus size). I have never heard of x87, but I look quickly; this is apparently a pure floating point coprocessor torn from the x86 architecture. Another architecture you'll see is the SPARC architecture, which is a completely different architecture and set of instructions from the x86 series.

Answer 2

Why are there so many processor architectures?

In the early days, just working on the processor was a significant achievement. Early builders designed the equipment material as simple as possible, just to get something working - they usually ended with sets of instructions that were very fancy.

Later, builders, not wanting to force programmers to recompile all their software, added new instructions, but left only the old instructions. (This is commonly called "barnacles compatibility").

People came up with dozens of innovations that simplified programming or accelerated or improved in another way - index registers, address registers, data registers, wider address registers, wider data registers, link register, interrupts, CALL routine routine, calculating the effectiveness of effective instructions with one instruction , pipelining, single multiplication, VLIW, etc. Many of these innovations required at least new instructions, if not completely updated instruction sets. (Other innovations, such as the cache, accelerated the work of processors without changing the set of instructions, so the new processor still starts all old programs without changes).

IBM's 1982 policy was to require at least 2 sources for all parts. (Even today, many manufacturers are reluctant to buy "single-source parts"). To convince IBM to buy Intel processors, Intel licensed its projects for AMD, a licensed second-source manufacturer. The lawsuit over this license was very public.

A long lawsuit between Intel and AMD has bothered many processor developers. When a new processor developer came up with new innovations, rather than adding phased instructions to the x86 instruction set or some other existing set of instructions - risking a lawsuit - Processor developers felt more comfortable using completely different instruction sets to demonstrate even relatively small innovations.

In several cases, two different people face conflicting innovations - each of them clearly surpasses the old processors before any was invented, but it is not possible to build a processor that supports both innovations at the same time.

Today, there are many different computer architectures .

Answer 3

The set of instructions may vary slightly; however, the key differences are the length of the registers and, as a result, the amount of address memory.

x86 has 32 bit registers x87 is a floating point extension of x86 x64 has 64 bit registers 

See also:

http://en.wikipedia.org/wiki/X87

http://en.wikipedia.org/wiki/X86

http://en.wikipedia.org/wiki/X64

Answer 4

There are also processor families, so the difference can be significant. Just think about RISC or the CPU stack .