Yeah, that was it's own system that had a lot of mismatches with how different OSes wanted to conceive of task switching.
Where Intel ended up was the xsave/xrestor family of instructions to save and restore processor state according to a bit flag argument of high level functional units. And that's really only because of how complex all of the extensions to x86 have been over the years; a fresh arch is probably just better off manually writing everything with normal loads and stores until right around the iret equivalent. Dumps between the register file and memory show up on perf traces anyway so it's generally a very optimized path in the CPU for general uses anyway.
Where Intel ended up was the xsave/xrestor family of instructions to save and restore processor state according to a bit flag argument of high level functional units. And that's really only because of how complex all of the extensions to x86 have been over the years; a fresh arch is probably just better off manually writing everything with normal loads and stores until right around the iret equivalent. Dumps between the register file and memory show up on perf traces anyway so it's generally a very optimized path in the CPU for general uses anyway.