LDUX/ldux ( Load Doubleword with Update Indexed)

Load Doubleword with Update Indexed
X-form
ldux RT,RA,RB

31 RT RA RB 53 /
0  6  11 16 21 31

EA <= (RA) + (RB)
RT <= MEM(EA, 8)
RA <= EA

Let the effective address (EA) be the sum (RA)+ (RB).
The doubleword in storage addressed by EA is loaded
into RT.
EA is placed into register RA.
If RA=0 or RA=RT, the instruction form is invalid.
Special Registers Altered:
None