[clamchowder]

(author here) Just a 32 entry BTB is technically a possibility from microbenchmark results, but the EIC7700X datasheet straight up says:

"a branch prediction unit that is composed of a 32-entry Branch Target Buffer (BTB), a 9.1 KiB-entry Branch History Table (BHT), a 16-entry Return Address Stack (RAS), 512-entry Indirect Jump Target Predictor (IJTP), and a 16-entry Return Instruction Predictor"

[phire]

Ah, that makes so much more sense.

So it does have a 2nd level BTB, it's just that it's labeled as IJTP and is potentially only used by indirect branches.

[clamchowder]

No, that's not a second level BTB in that regular direct branches don't seem to use it. It's only for predicting indirect branches.