Describe how CMO instructions match triggers. (#821)

* Add inst, reg, and field macros.

To help consistently format instructions, register names, and field
names.

* Describe how CMO instructions match triggers.

See e-mail subject:"Sdtrig and CMO".

* Rephrasing again.

* Refine language.

* Triggers only match CMOs when size=0 and select=0.

Address must be base address or the passed address, but should be the
address of every address in the affected cache lines.

* Rephrase CMO address comparison.

Refer to "virtual address covered by any of the affected cache lines."

* Rephrase CMO trigger compare values again.

* Rephrase which addresses are compare values for CMOs.

* Don't try to account for virtual address aliasing.