"Pushes Data into a Stack frame to allow the use of Registers that normally can't be used for operations"
stwu is also often used for indexing by i in loops, I think it'd be better to just say it's stw but the resulting address is also stored to the address register
xoris isn't intended to be a copy, usually or rA, rB, rB would be used for that (with the mr instruction being a macro for that); xoris does a bitwise xor but with the immediate logically shifted left 16 bits first
stwu is also often used for indexing by i in loops, I think it'd be better to just say it's stw but the resulting address is also stored to the address register
xoris isn't intended to be a copy, usually or rA, rB, rB would be used for that (with the mr instruction being a macro for that); xoris does a bitwise xor but with the immediate logically shifted left 16 bits first