22c:060 - Homework 5

2. For part c and e to work properly, the USE "hawk.macs" directive must be used.

   1. LIS     R3, 25

   2. LIL     R3, -250

   3. LIW     R3, #FFFFF666

   4. LIL     R3, 800000

   5. LIW     R3, #FADF00D

3. 1. LOAD    R3, #11000

      or
      

      LIL     R3, #11000

      LOADS   R3, R3

      
      

   2. LOAD    R3, #11000

      LOADS   R3, R3

      or
      

      LIL     R3, #11000

      LOADS   R3, R3

      LOADS   R3, R3

      
      

   3. LOAD    R3, #11000

      ADDSI   R3, 4

      LOADS   R3, R3

      or
      

      LIL     R3, #11000

      LOADS   R3, R3

      ADDSI   R3, 4

      LOADS   R3, R3

      
      

4. • (j)   There are two ways for the BR instruction to branch to itself:

     LOOP:   BR      LOOP

     or
     

             BR      -2

     
     both of these assemble to the same thing:
     

     0000000011111111

     
     
   • (o)

     ADDI    R0, R1, -100

     or
     

     ADDI    R0, R1, #FF9C

     or
     

     1111 0000 0110 0001 1111 1111 1001 1100

   • (p)   In ADDSI, the source register is the same as the destination register. Register 0 always contains the value 0 and attempts to store values in it are ignored. If the destination register is set to 0, then the hypothetical CMPSI would try add the value of the constant to the value 0 held in R0 which is not very meaningful because what a compare instruction is supposed to do is compare the constant with some unknown value in a given register.