Intel and AMD processors

[mamayao]

If processor design is proprietary, how is it that AMD and Intel can design compatible processors without collaboration

 

[jaguarskx]

Basically it is all about how the CPU architecture is designed to execute x86 and x64 instructions. There is no "one way" of doing it.

A simply analogy is an engine. All cars have an engine which allows the car to operate. However, not all cars use the same engine.

 

[CTurbo]

Technically, AMD and Intels processors are not compatible. They are very very different.

 

[MU_Engineer]

If processor design is proprietary, how is it that AMD and Intel can design compatible processors without collaboration

The reason you can run the same programs on either an AMD or Intel processor is because both manufacturers use the same general set of low-level CPU instructions (the x86_64 instruction set.) The short answer is that there is actually a bit of collaboration between the two companies as far as instruction sets are concerned.

The long answer goes back three decades. IBM was the king of the computing world and decided to build their first PC, the IBM 5150 PC. IBM demanded that whoever made the CPUs for the IBM PC have a second source lined up for manufacturing additional processors if IBM's demand outstripped the maker's own supply. (This was common practice back in those days as everybody who made ICs had fabs.) Intel got the contract for the IBM PC's CPU and picked the reasonably well-known microprocessor manufacturer AMD to second-source the IBM PC's 8088 CPU. Little-known Seattle software firm MicroSoft got the contract to do the OS for the IBM PC as IBM couldn't be bothered to put a real "enterprise" OS like AIX on the IBM PC, and thus IBM entered the PC world. They sold a lot of IBM PCs and the follow-up models, which used successive generations of Intel-designed and Intel/AMD/IBM-manufactured x86 CPUs and Microsoft DOS.

Famously, Compaq reverse-engineered the IBM PC's BIOS without violating 1980s copyright laws (and generated the PC clone industry. These all used the same recipe of x86 CPU and Microsoft DOS but didn't have the same multiple-source demands for CPU makers. Intel kept AMD and a couple others on as additional CPU foundry sources for a while. Intel decided to start to keep CPUs to itself starting with the 80486 and infamously broke the second-source agreement with AMD in 1991 and tried to prevent AMD from making 80486-compatible CPUs. The outcome of that contract breach lawsuit was an agreement involving the royalty-free cross-licensing of patents between Intel and AMD. That is how AMD is able to use instruction set features Intel designed such as SSE and Intel gets to use features AMD designed, such as the x86_64 instruction set extensions.

 

[jacobian]

The instruction language is the same, but the implementation is different DUH. That's all software needs to know.