IT TTT block in assembly language
Quoting from ARM's information center about the Cortex M4:


  IT{x{y{z}}} cond
  where:
  
  x Specifies the condition switch for the second instruction in the IT
  block.
  
  y Specifies the condition switch for the third instruction in the IT
  block.
  
  z Specifies the condition switch for the fourth instruction in the IT
  block.
  
  cond Specifies the condition for the first instruction in the IT block.
  
  The condition switch for the second, third and fourth instruction in the IT block can be either:
  
  T
  Then. Applies the condition cond to the instruction.
  
  E
  Else. Applies the inverse condition of cond to the instruction.
  
  The IT instruction makes up to four following instructions conditional. The conditions can be all the same, or some of them can be the logical inverse of the others. The conditional instructions following the IT instruction form the IT block.
  
  The instructions in the IT block, including any branches, must specify the condition in the {cond} part of their syntax.


Read more here... This is where I got the information from.