More or less like Stockfish of today, most likely, except much more constrained: No parallel search. Much less reliance on lookup tables due to memory constrai

More or less like Stockfish of today, most likely, except much more constrained: No parallel search. Much less reliance on lookup tables due to memory constraints. Simpler evaluation function. But fundamentally the architecture of engines in those days was more or less the same: alphabeta(or some variation of it), with quiescence search and a static evaluation function, likely using piece-square tables. Lookup these things on chess programming wiki for a more detailed exposition.