Cbuildcap and ctestsubset do not use DDC

[francislaus]

This should close #18

I decided to not make cs1==0 RESERVED because it is a valid input.

[francislaus]

I had a longer discussion with @PeterRugg and he explained that cbuildcap also clears the otype if it is successful. In the current form cbuildcap can be used for tag clearing, but this would change if the spec got more otypes later.

[francislaus]

What was the reasoning for not having a ccleartag instruction? @tariqkurd-repo

[andresag01]

@francislaus: The expectation was ccleartag is not a common instruction, so it was not included in the current proposal to save encoding space. It could be added if there is a strong use-case for it, or as a pseudo-instruction implemented using cbuildcap like @arichardson suggested.

@tariqkurd-repo, what do you think about ccleartag?

[francislaus]

@tariqkurd-repo What were your thoughts about ccleartag?

[arichardson]

I'm happy with this being merged as is and I've filed #94 for the CClearTag question.

[arichardson]

I'm happy with this being merged as is and I've filed #94 for the CClearTag question.

And by merge I mean squash+merge to avoid the fixup commits in the history.