The 74182

The 74182 (or AM2902) was a high_speed, lookahead
carry generator, designed to work with a group of four
74181 ALU ICs.

For more details, please consult/dissect the 74182
datasheet.

Now a schematic, how to build a 16 Bit ALU with
one 74182 and four 74181:

Cn is the carry input,
Cn+4 is the carry output.
/P=0 indicates, that the 74182 will propagate a carry through,
/G=0 indicates, that the 74182 will generate a carry.

And because of the /P and /G outputs of the 74182,
it's also possible to link multiple levels of 74182 ICs
together for forming up ALUs with a word length of more
than 32 Bit.

Example: 64 Bit ALU (16*74181, 5*74182)

The circuitry inside the 74182:

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