The 11 had a lot of CPU variants and instruction set extensions -- https://sourceware.org/binutils/docs/as/PDP_002d11_002dOptions.html

So T11's one is "baseline" + "Limited EIS" + "MxPS"; full EIS also has ASH, ASHC, MUL and DIV.

1801VMx extensions are briefly described here -- http://pdp-11.ru/mybk/doc/PDP11.TXT, there's also a full technical manual.