How to STR a value larger than #0x00FF into memory

I'm working with an FPGA that has a 40-pin bidirectional parallel port. To set the direction of the pins, I need to change the value of memory location 0xFF200074 to 0x0000FFFF. However, when I try to MOV #0x0000FFFF into a register, I get an error saying it's too large. I'm trying to move that value into the register so I can subsequently STR it into memory.

I don't believe I'm able to manipulate memory directly with ARM. But there must be an easy way to do this and I am just not seeing it.