The adder at the heart of Intel's 8087 floating-point chip

kens

Author here for your 8087 questions. I find adders and ALUs interesting because they are key to the performance of a system and every system implements them differently.

throwaway152321

Do you have any insights on how power was delivered to these circuits? Maybe it's done in the metal layers that were dissolved? Also, is it correct that there is no on die capacitance surrounding these circuits? Thanks for the great article.

nine_k

/* It's a bummer that there is addition but no vipition. */

JdeBP

It is interesting that over the years people have produced synthesizable RTL HDL for the 8086/8088 and later, with varying degrees of fidelity, but no-one seems to have produced similar for the 8087.

librasteve

great post … thanks for all the work personally I would like to see a compare and contrast between the Intel 8087 (built around an full width adder), 287 and the Weitek 1167 (built around a full width mac and barrel shifter) as you note, all these parts were pushing the transistor limits of their day PS. and the Inmos T800 had a log shifter … so a compromise between those extremes