18. Immediate instructions

• Using immediate operand -- the second operand which is a constant

  • Note: the constant is 16-bits, sign-extended to 32-bits

  
      # add/subtract/and immediate:
      # Instruction             # Meaning in pseudocode
      addi $t1, $t2, 4          # $t1 = $t2 + 4
      subi $t1, $t2, 15         # $t1 = $t2 - 15
      andi $t1, $t2, 0x00FF     # $t1 = $t2 & 0x00FF
  
      # set if less than immediate:
      slti $t1, $t2, 42         # $t1 = $t2 < 42 ? 1 : 0
  
  

• Other other immediate instructions: ori and xori