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by dbcurtis 807 days ago
If you were an instruction pairing whiz, you could get pretty close to 2 IPC on the Pentium I for certain kernels.

The thing that Seymour had going for him at CDC is that he didn't bother with synchronous exceptions. On x86 (I worked on a late 486, Pentium I, Pentium II and Itanium II) you absolutely must have synchronous exceptions for backward compatibility. Debugging an exception on 6600 was a hair-tearing exercise, because the PC point somewhere near, not at, the instruction that raised, and there may be a swiss-cheese window of instructions that did not complete somewhere before that. Loads of fun for one and all. (I used 6600/7600's while working on Cyber 203/205 at CDC).