Does that mean that the shifter is actually capable of doing rotates? Otherwise the negation part doesn't make any sense.
If you have 0xf0 and want to shift it three bits to the right to get 0x1e, no amount of negated-amount left-shifting is going to do that unless the instruction is a rotate.
If, on the other hand, you can do a 8-bit rotate left of 8-3 = 5 bits, that would produce the same result and need that "negation" (which is actually an inversion).
Does that mean that the shifter is actually capable of doing rotates? Otherwise the negation part doesn't make any sense.
If you have 0xf0 and want to shift it three bits to the right to get 0x1e, no amount of negated-amount left-shifting is going to do that unless the instruction is a rotate.
If, on the other hand, you can do a 8-bit rotate left of 8-3 = 5 bits, that would produce the same result and need that "negation" (which is actually an inversion).