A Collection of Code from CDA-4102: Computer Architecture.
A major topic in this course is: Unix Processes in C, so there is a YouTube tutorial playlist.
The book following this course is Computer Systems: A Programmer's Perspective, 3/E
- This book uses programming in C language for assignments.
Another good book for Computer Architecture is: Structured Computer Organization
- This book is more about hardware and does not include programming.
C Language Placeholders List and examples of usage.
- Remember that
scanf()is vulnerable to buffer overflow, to usefgets()instead, as discussed in the article. - Remember in C: DON'T FORGET TO CLEAR THAT INPUT BUFFER: Stack Overflow
C File Handling:
- Reference for C File Handling with examples.
- C File Handling examples.
- C Files from W3 Schools.
- C Program to Copy One File to Another File
Architecture References:
- x86_64 Reference Sheet: This is what I am Running
- X86_64 Register and Instruction Quick Start Wiki Page
- x86 Assembly/X86 Architecture
GDB Debugging:
- Harvard CS50 GDB Tutorial: A Great Introduction to GDB.
- Low Level Learning: An Excellent GDB Walkthrough Example.
- CppCon 2022 Back To Basics: Debugging Strategies and Intro to GDB.
- GDB MasterClass by Mike Shah.
- GDB Quick Reference Guide.
- Debugging With GDB 10th Edition HTML Web Reference Manual.
- Debugging With GDB 10th Edition Reference Manual PDF.
run # (short: r) # Start the program
start # Synonymous to (b main && run). Puts temporary breakpoint at main()
next # (short: n) # Next Line of Code / Step OVER: Goto Next Line & Execute current line
nexti # Next Instruction: Goto Next Line of ASSEMBLY & Execute current line of ASM.
list # (short: l) # List/Print 10 lines of code next to currently executing line of code
step # (short: s) # Step INTO function call at current line
stepi # Step a single assembly instruction
finish # (short: fin) # Finish the execution of current function
continue # (short: c) # Resume execution (After a breakpoint)
refresh # (short: ref or Ctrl+l) # Repaint the interface
quit # (short: q) # Quit
break funcName # (short: b funcName) # Set breakpoint at function funcName
b file::line # Set breakpoint at line in file
delete # Delete all breakpoints
delete breakpoint_no # Delete breakpoint breakpoint_no
disable # Disable all breakpoints
make binaryName # recompile binaryName (useful to test after 'p var = value' changes)
layout type # Set the window layout ("src", "asm", "split", or "reg")
tui reg type # Set the register window layout ("general", "float", "system", or "next")
lay next # Cycle through the layouts of gdb
tui disable # Disable TUI display mode.
tui enable # Enable TUI display mode.
tui reg # TUI command to control the register window.
print var # (short: p) # Print the value of variable / object var
p var = value # Force set value to the var (short for print)
set variable expression # Set a variable to value, e.g. `set variable x=20`
set (expression) # Works like set variable
ptype expr # Detailed print of datatype of expr
info locals # Variables in local scope
info variables # Variables declared outside current scope
info functions # Names and datatypes of all defined functions
info registers # Dump integer registers to screen / View Register Values ar time of crash
info all-registers # Dump all registers to screen
info b # List all breakpoints
whatis expr # Print datatype of expr
backtrace # (short 'bt') # Print backtrace: Call stack history
where # Same as backtrace
shell cmd # Run shell command cmd from gdb prompt
python gdb.execute(cmd) # Run a gdb command cmd from python prompt
set print pretty on # Enable pretty printing (Put in ~/.gdbinit)
$ gdb -c core.num # Examine the dumped core file from a SIGSEGV(shell command)
break _exit # Breakpoint at exit of program
watch var # Stop when var is modified
watch -l foo # Watch foo location
rwatch foo # Stop when foo is read
watch foo if foo>10 # Watch foo conditionally
command breakpoint_no # Run user listed commands when breakpoint is hit (End commands with 'end')
file executable # Load the executable for debugging from inside gdb
info # GDB Manual Pages
# Examine Function: Used After Crashes like 'Segmentation Faults'
x/nfu addr #
x addr #
x/ # Examine function: used to examine registers and see what address they point to
# different output examples:
x/x $eip # examine the value of eip in hexadecimal
x/o $eip # examine the value of eip in octal
x/u $eip # examine the value of eip in unsigned base-10 decimal
x/t $eip # examine the value of eip in binary
x/i $eip # examine the instruction
x/i $pc # examine the instruction at the program counter (before the crash)
x/2xb $eip # examine first 2 bytes in hexadecimal
x/1xh $eip # gives the same amount of bytes but in one line ('h' stands for half-word which is a short (2 bytes))
x/x $esp # examine the value of esp in hexadecimal
x/o $ebp # examine the value of ebp in octal
x/u $eip # examine the value of eip in unsigned decimal Base-10
x/t $edi # examine the value of edi in binary
print $eip # will make a variable for it and display the value and address
x/2xw $1 # Needs Description...
# Number Base / Radix:
o : octal
u : unsigned decimal
t : binary
x : hexadecimal
# Sizes:
g : giant (8 bytes) # 64-bit word: 8 bits per byte * 8 bytes
w : word (4 bytes) # 32-bit word: 8 * 4 = 32
dw : double word (4 bytes) # 32-bit word: 8 * 4 = 32
h : half word (2 bytes) # 16-bit word: 8 * 2 = 16
b : byte (1 byte) # 1 byte = 8 bits
# and and by the way gdb uses LITTLE ENDIAN format
# so the bytes will be reversed for example:
x/4xb $eip: 0x7c , 0x4f , 0x45 , 0x64
x/1xw $eip: 0x64454f7c