CSE 378 - Spring 1998

Machine Organization and Assembly Language Programming

Problem Set #2

Due Wednesday, April 15, 1998

• By the end of the second week, read Chapter 4, Section 4.4, plus Chapter 3, Sections 3.5 through 3.15, and Appendix A, Sections A1, A2, A6, and A9.  Also look through Appendix A Section A10 (though you will not be required to know every instruction, it will help you to become familiar with them).

• Do the following problems, and hand in the answers by the start of class on Wednesday, April 15.
• Note that the answers to many of the programs can be verified or even determined by using Spim.

1. Problem 3.2.  (? pts)
2. Show the minimal sequence of instructions for this C statement:

   x[8] = x[4] - y;

   Assume that y's value is in register $t0 and the array x contains 32-bit ints and has a base address of 0x44567818.

   (4 pts)

3. Problem 3.6. (5 pts)
   
4. As discussed on p. 157 and summarized in Fig 3.37, pseudoinstructions are not part of the MIPS instruction set, but often are used in assembly language programs.  For each pseudoinstruction in the table, produce a minimal sequence of actual MIPS instructions to accomplish the same thing.  You may need to use $at for some sequences.  In the following table, big refers to a specific number that requires 32 bits to represent, and small to a number that requires only 16 bits.  (13 pts)
   
   

   Pseudoinstruction	What it does
   move $t5, $t1	$t5 = $t1
   clear $t2	$t2 = 0
   li $t5, small	$t5 = small
   li $t5, big	$t5 = big
   lw $t2, big($t3)	$t2 = Memory[$t3 + big]
   addi $t1, $t2, big	$t1 = $t2 + big
   beq $t3, small, L	if ($t3 = small) goto L
   bne $t3, big, L	if ($t3 != big) goto L

    

5. Problem 3.9.  (5 pts)
6. Problem 3.23. (4 pts)
7. Problem 4.21. (2 pts)
8. Problem 4.22. (3 pts)
9. Problem 4.41. (2 pts)