Here's the story behind it
IBM was involved in the development of x86 systems since their inception, at some point designing and manufacturing x86 processors intended for PCs as well as embedded systems. Over the years, the company has made significant contributions to the evolution and growth of the x86 platform.
Cyrix, founded in 1988, specialized as a microprocessor developer and was known for creating high-performance math coprocessors for the 286 and 386 microprocessors. The company worked closely with IBM, producing some of their most notable products during the Intel Pentium era, specifically the Cyrix 5x86 and 6x86 CPUs.
After a successful run, Cyrix was acquired by National Semiconductor in 1997. Following this acquisition, it eventually folded into one of Texas Instruments' divisions, illustrating the dynamic and fast-paced evolution of the microprocessor industry.
VIA Technologies, another significant player in the x86 CPU manufacturing industry, was particularly active during the 1990s. The company carved a niche for itself by specializing in low-power solutions. Its acquisition of IDT Centaur marked its debut in the microprocessor market, ushering in the production of the VIA C3, VIA C7, and VIA Nano processors. As of the present, VIA continues to produce chips through Zhaoxin, a joint venture with the Shanghai Municipal Government, which predominantly caters to the Chinese market.
In contrast, Motorola, despite being one of the first semiconductor companies in the world and boasting a rich history of developing microprocessors used in a wide variety of applications, never produced an x86 class processor for the PC market. Motorola's significant contributions have been in other areas of microprocessor technology.
In a strategic move, Motorola's semiconductor division was spun off into two separate entities: ON Semiconductor, which continues to operate, and Freescale Semiconductor. Freescale was subsequently acquired by NXP in 2015, and later, Qualcomm bought NXP, demonstrating the continued consolidation and reshaping of the semiconductor industry.
Therefore, among these, Motorola is the company that did not make x86 CPUs.