0b01 B7B6 B5B4|B3B2 B1B0
0b10 B7B6|B5B4|B3B2|B1B0
-This gwts interesting. First, the simpler case: Cat() with a 3-bit slice.
+This gets interesting. First, the simpler case: Cat() with a 3-bit slice.
The end result (assuming `Cat(a[0:3], b)`) is:
+* one 11-bit result for elwid=0b00
+* two 7-bit results for elwid=0b01
+* four 5-bit results for elwid=0b10
+
+ elwid | | | | | |
+ 0b00 |B7 B6B5B4 B3B2 B1B0A2A1A0
+ 0b01 |B7B6 B5B4AaA9 A8| B3B2 B1B0A2A1A0
+ 0b10 B7B6Ae AdAc|B5B4AaA9 A8|B3B2A6 A5A4|B1B0A2A1A0