AMD–Chinese joint venture
The AMD–Chinese joint venture is the agreement between the semiconductor company Advanced Micro Devices (AMD) and China-based partners to license and build x86-compatible CPUs for the Chinese-based market. It is an attempt to reduce the Chinese dependence on foreign technology, but was negotiated and agreed to well before the 2018 trade war between the US and China. It is similar to the Zhaoxin joint venture supported by VIA Technologies.

Structure
AMD has received permission from the US Department of Defence and Department of Commerce to export the Zen 1 core design to China. Due to legal restrictions AMD has set up multiple companies to allow licensing of x86 technology to China. The overarching joint venture is the Tianjin Haiguang Advanced Technology Investment Co. Ltd. (THATIC). THATIC is owned by "AMD and both public and private Chinese companies, including the Chinese Academy of Sciences": however its major share is reportedly owned by AMD itself.

2 further joint-ventures have been set-up: (1) Haiguang Microelectronics Co. Ltd. (HMC), and (2) Chengdu Haiguang Integrated Circuit Design Co., Ltd (Hygon). AMD and THATIC own differing proportions of these companies. HMC owns the local intellectual property of the chip and subcontracts the manufacturing of the chip. Hygon designs the chip and markets and sells the processors.

History
The joint venture was announced by AMD in 2016. The first processor was released in 2018. At the Computex 2019 trade show, AMD CEO Lisa Su confirmed that the licence will be limited to the original Zen architecture, and would not be extended to Zen 2.

On June 24, 2019 the US government placed one of the parent companies, and thus the joint venture, on its export control Entity List, which bans further technology transfers from AMD and possibly hampers its existing operations. The opinion of Anandtech is that further AMD involvement in the joint venture will be minimal due to the ban.

Microprocessors

Hygon SOC 
The initial microprocessor created in 2018 is the Hygon Dhyana system on a chip. It is noted to be a variant of the AMD EPYC and is so similar that "there is little to no differentiation between the chips." It has been noted that there is "less than 200 lines of new kernel code" for Linux kernel support, and that the Dhyana is "mostly a re-branded Zen CPU for the Chinese server market."

Testing in 2020 suggested that "integer performance is essentially identical, however the floating point and RDRAND and RDSEED instructions' performance has been reduced" from the equivalent Zen 1 processor. The cryptography extensions like AES have been replaced by Chinese versions called SM2, SM3 and SM4 which are according to Anandtech are very similar to ECC(-based), SHA-256 and AES-128 algorithms respectively. AVX/AVX2 was also disabled, but the research has suspected that it happened due to a bug rather than was done intentionally.

See also
 Zhaoxin – a similar joint venture to produce x86 processors between VIA Technologies and Chinese partners
 EPYC – the AMD processors that the Hygon Dhyana is based on

References

Advanced Micro Devices
Advanced Micro Devices x86 microprocessors
Microprocessors made in China
Technology companies established in 2016
Technology companies of China
Chinese-foreign joint-venture companies