are directly equivalent to the strict Program Order Execution of
their element-level operations.
+ R0,CA = A0+B0+CA
+ |
+ +----------+
+ |
+ R1,CA = A1+B1+CA
+ |
+ +----------+
+ |
+ R2,CA = A2+B2+CA
+
Thus, due to sequential execution of `adde` both consuming and producing
a CA Flag, `sv.adde` is in effect an alias for Vectorised add. As such,
implementors are entirely at liberty to recognise Horizontal-First Vector
adds and send the vector of registers to a much larger and wider back-end
-ALU.
+ALU, and/or short-cut the intermediate storage of XER.CA on an element
+level and implement a Vector-aware carry propagation algorithm
+in back-end hardware that need only take the first incoming XER.CA and
+only store the last XER.CA. The size of the underlying back-end SIMD ALU
+is entirely at the discretion of the implementer.
# Multiply