[U-Boot-Users] the difference between two instructions

Hello guys, Here are two lines of arm assemble code: ldr pc, _undefined_instruction ldr pc, =_undefined_instruction

What's the difference between them? Do they act in the same way in some cases? I know it seems to be independent of u-boot, but I just can't solve it and have been puzzled today after searching for answers on the web. Thank you for your advice.

Best regard,

Min Chan