The assembler you're looking for, is called YUL. [0]

You can find much of that code here [1], but unless you have a Honeywell, it isn't much help. yaYUL is a modern remake, and can assemble most of the Apollo code.

[0] https://www.ibiblio.org/apollo/Documents/agcis_13_yul.pdf

[1] https://klabs.org/history/software/yul/