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J. Peterson

@kenshirriff If the PLA bits are defined in the long thin structures on the right, I wonder if the missing bits are at the bottom? That section is suspiciously devoid of the various marks the rest of the structure has.

Amazing find!

1 comment
Ken Shirriff

@isonno Good eye to spot the unused entries at the bottom! Those aren't the missing entries, though. The mathematical table got encoded into Boolean equations, which are stored in the PLA. There is not easy mapping between the table and what you see on the die. In fact, the fixed Pentiums have *fewer* entries in the PLA due to the way the equations work out.

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