Number (4): Everything in this space must add up to 4. The answer is 4-4, placed horizontally.
The 386 microcode sequencer has a one-cycle pipeline delay: when a jump or RNI (run next instruction) is decoded, the micro-instruction immediately after it has already been fetched and will execute before the jump takes effect. This "delay slot" is a basic property of the sequencer, and the microcode is written to fill it with useful work rather than waste a cycle on a bubble. The examples in the PTSAV section above show this: at 582/5AE, the micro-instruction after LCALL executes before the subroutine begins.
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It's perfectly valid to add input filtering on top of type=email if you want to further restrict the input set. Maybe you hate people with gmail addresses or only want to allow email addresses at your local firm (both examples from before!). In that case, having a more restrictive pattern makes sense.
Tom Hardin details his days wearing a wire for the feds.