From "Using GECOS Programs in Multics" from the MULTICS System Programmer's Manual (1967):

"The TMG table interpreter is a more difficult case. It was written originally in CDC 1604 assembly language, edited over to IBM 7040 assembly language, converted to IBM 7090 BEFAP by defining macros for the 7040 opcodes, and finally converted to GE 635 GMAP by further defining macros for the 7090 op-codes. The program has gradually lost almost all its commentary and any trace of coherence it may ever have had. There is little likelihood that any further mechanical translation of this program is even possible." https://www.multicians.org/mspm/bx-17-00.670824.gecos-program-usage.pdf