From The Free On-line Dictionary of Computing (19 January 2023):
ISPS
Instruction Set Processor Specifications. Operational
hardware specification language. Successor to ISPL.
["Instruction Set Processor Specifications", M.R. Barbacci et
al, IEEE Trans Computers, C-30(1):24-80 (Jan 1981)].
[Bell, Newell, Siewiorek, Barbacci 1982?]