Brad Cox had a concept of Software ICs, in the chip sense, that align with this. He envisioned these as sharable objects rather than just libraries, but either way that’s the present we’ve been given accidentally.
Motorola developed the MC6839 which allowed one to do floating point math with the MC6809. The MC6839 was not a floating point CPU, but an actual 8K ROM of 6809 machine code that implemented floating point math (with position independent code so it could be mapped anywhere in the memory map). This is about the closest I have ever seen of a "software IC" in my life.
