CS 2734 Computer Organization II

In this laboratory you will be writing C code to dis-assemble an input MIPS machine-language program. (It is permissible to use C++ or Java for these assignments.) To ``dis-assemble'' means to convert the machine-language program back to some form of assembler language.

• Based on the input machine-language instruction, create a symbolic form using the following steps:
  • Use the program of Lab 9 to tear the instruction into its component fields (some representing overlapping portions):
    • op: op code, bits 26-31
    • rs: read reg #1, bits 21-25
    • rt: read reg #2, bits 16-20
    • rd: write reg, bits 11-15
    • sh: shamt, bits 6-10
    • ft: funct, bits 0-5
    • ai: addr/immed, bits 0-15
    • ta: target addr, bits 0-25

  • Using the op field, and the ft field in case the op field is zero, determine the symbolic operation as a character string.

  • Convert any register numbers rs, rt, and rd to the proper strings.

  • For R-type instructions, one only needs to output the op and the registers in the proper order.

  • For beq and bne instructions, get the offset address, ai, and multipy this by 4. (You might use the form "PC + 36".)

  • For lw and sw instructions, get the offset, ai, and put it into the instruction (without multipying by 4) in the proper place.

  • For the jump instruction (j), get the address from ta and output in the form "J [ta/4]".

• Create a new directory for this assignment.

• Practice your program on the following Sample input.
  Here is the output that my own program for this lab produced: Sample output.
  

• You should check off your program with the lab TA. You must hand the source code to the TA before he starts checking off the project.