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

[Min Chen]

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