actually maxu. and maxs. as well as minu. and maxu.
these are needed for potential saturation scenarios
overflow occurs when src2 "wins" over src1. swapping
the operands allows the opposite detection with no
need for a 2nd operation.
when used in sv with a scalar src2 it can be used to
clamp *and detect* when clamping occurred on an entire
also need Rc=1 variants which merge "cmp" functionality into
the instructions. has to be done carefully because it's not
exactly the same as normal Rc=1, it is more like "cmp".
combined cmp with max:
* the lt flag is set if RA<RB
* the gt flag if RA>RB
but XER.SO being set can detect if the entire batch is set.
the dependencies however are hell. it would be better to have
a CRfield vector "reduction" operation, afterwards.
CR0.GT being set is effectively "src2 wins"
CR0.LT is effectively "src1 wins"
CR0.EQ is effectively "nobody wins"