Computer Organization Lab 09

CSCI 2500 — Computer Organization
Lab 09 (document version 1.1)
• This lab is due by the end of your lab session on Wednesday, November 6, 2019.
• This lab is to be completed individually. Do not share your code with anyone else.
• You must show your code and your solutions to a TA or mentor to receive credit for each
checkpoint.
• Labs are available on Mondays before your lab sessions. Plan to start each lab early and
ask questions during office hours, in the discussion forum on Submitty, and during your lab
session.
This lab will consider 32-bit binary MIPS instructions. For this lab, we’ll implement functions to
decode the binary into its operational components. See the comments in file lab09.c for detail.
1. Checkpoint 1: For the first checkpoint, use C to finish implementing the push_lsb_bit()
and pop_lsb_bit() functions. Review the print_b32() function, too, though do not change
it.
Begin by downloading the lab09.c code, which provides fill-in-the-blank skeletal code for
these (and other) functions. Verify that the test cases given in main() provide correct results,
but also add additional test cases.
2. Checkpoint 2: For the second checkpoint, continue to add to the lab09.c code by implementing the isolate_bits() function. Uncomment the test cases in main() to test your
isolate_bits() function. Further, add additional test cases to be sure your function is
correct.
3. Checkpoint 3: For the third checkpoint, complete the lab09.c code by implementing the
decode_inst() function. As part of this function, display the decoded instruction opcode
using the format shown in the commented code. This function must also display the ALU
control lines, when applicable.
You only need to implement decoding for the “simple” instruction set we looked at in Chapter
4. See the second page of csci2500-f19-ch04a-slides.pdf.
Uncomment the test cases in main() to test your decode_inst() function. Further, add
additional test cases to be sure your function is correct.
As a hint, in addition to the textbook, consider using spim to see what the decoded opcode
codes, funct codes, etc. are for various instructions.