Mode types:
* **predicate zeroing** (sz, dz) if predication is enabled will put zeros into the dest (or as src in the case of twin pred) when the predicate bit is zero.
-* **ffirst* or data-dependent fail-on-first: see separate section.
+* **ffirst** or data-dependent fail-on-first: see separate section.
* **sat mode** or saturation: clamps the result to a min/max rather than overflows / wraps. allows signed and unsigned clamping.
* **pred-result** will test the result (CR testing selects a bit of CR and inverts it, just like branch testing) and if the test fails it is as if the predicate bit was zero. When Rc=1 the CR element (CR0) however is still stored in the CR regfile. This scheme does not apply to crops (crand, cror).