Description
Description:
In this project, you will create a simple ARM(Stumpyleg)v8
dissasembler. Your dissasembler will read a binary file containing an ARM program
in machine code and generate the assembly code for the given ARM program.
You
will not have to implement exception/interrupt handling and we will not use all of
the LEGv8 instructions. The instructions will follow simplifications as outlines in the
zybook Ch2. You will use this code in subsequent projects so do a good job and test
it competely.
Change Notices: As in real life I reserve the right to add to the project whenever I
want to. In real like you would charge more. In this life you just get to spend more
(time). Implication: You should make sure your code is constructed to be easy to
add additional instructions.
Implementation: You must implement this program in Python 2.7
Details: Refer to theARM instruction set architecture in your book. I will be
creating an achitecture document for the instructions we are using just to simplify
lookup but its not ready yet. Part 1 – A summary of instructions is attached.
Memory Layout: Memory will be aligned on word. This means that you will start
your program on mem location 96 and then increment by four bytes 96, 100, 104,
108. This will become obvious once you see an example output.
Instructions Covered:
You will be given an input file containing a sequence of 32 bit instruction words.
Assume that the first instruction is at memory address 96. The final instruction in
an instruction sequence is ALWAYS a “BREAK” instruction. Following the break
instruction is a sequence of 32 bit 2’s compliment signed integers for the program
data if there is program data.
These continue until the end of file. The break
instruction is a bit of an issue since ARM does not implement this exact instruction
so I will describe what I want you to use for “BREAK” in a section below.
Your simulator/dissassembler must support the following ARM instructions:
ADD, ADDI, SUB, SUBI
LSL, LSR, AND, ORR, EOR
LDUR, STUR
CBZ, CBNZ
MOVZ, MOVK
B
NOP
Notes on instructions:
ADDI, SUBI – the immediate value will be treated as just that, a
signed integer that needs to be added or subtracted.
SHIFTS – The shamt amount will be integer describing places to
shift. The real ARM instruction is more complex.
CNBZ , CBZ – Although the way the actual assembly is written is
with a tag, we are going to modify this to have the number of
words offset from the current position of the PC. So if the
branch is just to the next instruction, there will be a 1 in the
appropriate CB instruction field.
BREAK – Use the following coding for BREAK:
1 11111 10110 11110 11111 11111 100111
OPCODE – 203810
MASK 0x1FFFFF = 203159110
NOP – 0x0 = 0000 0000 0000 0000 0000 0000 0000 0000
Execution:
Your program must accept command line arguments for execution. The following
and only the following arguments must be supported in exactly the way I am
showing it:
$ python team#_project1.py -i test1_bin.txt -o team#_out
Please show some thought and don’t enter “team#”! If you have any questions,
make sure you understand. I will not be happy if I have to mess around when my
automation runs your program.
Your program will produce 1 output file named named team#_out_dis.txt, which
contains the disassembled program code for the input ARM machine code.
Your program will be graded both with the sample input and output provided to
you, and with input and output that is not provided to you. It is recommended you
construct your own input programs for testing.
WARNING: I AM DEAD SERIOUS ABOUT THE FOLLOWING!!!!!
Output: The dissembled output file should contain one line per word in the input
file. It should be separated into 4 columns, each separated by tab character.
The
columns contain the following information:
1) The binary representation of the instruction word. If the word is an
instruction (as opposed to memory data after the BREAK instruction), the
instruction should be split into six groups of digits: 8 bits which is the
smallest opcode size, three more bits covering the largest opcode, four
groups of 5 bits, and a final group of 6 bits.
2) The address of the memory location (in decimal)
3) If it is an instruction, print the operation, followed by a tab character,
then print each argument separated by a comma and a space ( “, “).
Instructions and arguments should be in capital letters. All integer values should be
in decimal. Immediate values should be preceded by a # sign. Be careful and
consider which instructions take signed values and which take unsigned values. Be
sure to use the correct format depending on the context. Output exactness is a goal
of the project just as it would be if this was for a real customer!
You output will be graded with the DIFF command. Test your output against the
provided sample outputs! Any differences reported by the DIFF command are
assumed to be incorrect output! That is why the formatting is so prescribed!!!!!!!!! If
you don’t follow it you will get hammered on the grading. 🙁
What to turn in: Your source file. A README.txt file indicating how to run your
program on LINUX!! Also, it should contain the names and txstate netIDs of your
group members. You can develop on Windows, but your program will be graded on
Linux on my mac powerbook. The executable must be named “team#_project1.py”.
( # is replaced by your team number) I also want a test input file you ran –
preferably the one I gave you – and the output for the test file. This is case your
code will not run MY final test file.
You should turn in one zipped folder with all the files in it with the folder name
“team#_project1”. ( # is replaced by your team number) I want to be able to
download the zipped folder from TRACS in my testing program, unzip it, and run
your code.
Misc:
Think about all data structures before you start. If you want me to review your plan,
come by my office hours. I will tell you what I would do and its your funeral if you
do something different.
The basic idea for the disassembler is a for loop to march through all of the
instructions.
We will talk about unit testing. I cannot emphasize enough about developing your
own set of tests since the ones I give you are not complete!!
The bulk of your code will be contained in a python class and be executed by a
function called run. I will describe the layout of the code in more detail in class so
you should be there.
Instruction Summary for Projects
Instruction OPCODE OP Size
(base 10)
11 bit OPCODE range Instruction
Start End Format
B 000101 6 160 191 B
AND 10001010000 11 1104 R
ADD 10001011000 11 1112 R
ADDI 1001000100 10 1160 1161 I
ORR 10101010000 11 1360 R
CBZ 10110100 8 1440 1447 CB
CBNZ 10110101 8 1448 1455 CB
SUB 11001011000 11 1624 R
SUBI 1101000100 10 1672 1673 I
MOVZ 110100101 9 1684 1687 IM
MOVK 111100101 9 1940 1943 IM
LSR 11010011010 11 1690 R
LSL 11010011011 11 1691 R
STUR 11111000000 11 1984 D
LDUR 11111000010 11 1986 D
EOR 11101010000 11 1872 R
NOP 00000000000 11 0 R
BREAK 1 11111 10110 11110 11111 11111 100111
OPCODE – 203810
MASK 0x1FFFFF = 203159110
