x86-64

I'm having problem understanding this exercise. I'll try my best to give my reasoning and I hope you guys can give me an idea what each line of code demonstrates. The Assembly we use is x86 assume the value stored in %rax = x xorq %rax, %rax // value stored in %rax: x ^ x = 0 addq $-1, %rax // value stored in %rax: 0 - 1 = -1 movq %rax, %rbx // value stored in %rbx: -1 or 0xFFFFFFFF shlq $2, %rbx shrq $1, %rbx // left shift by 3 total, so value stored in %rbx: 0x7fffffff8 addq %rbx, %rax // value stored in %rax: 0x7fffffff9 For the last line, my professor says we actually computing (TMax-1)-1,

I'm using Python 2.7 on 64-bit Linux. I have the following Python script witch should execute a simple Hello World shellcode. import urllib2 import ctypes shellcode = "\xb8\x01\x00\x00\x00\xbf\x01\x00\x00\x00\x48\xbe\xd8\x00\x60\x00\x00\x00\x00\xba\x0e\x00\x00\x00\x0f\x05\xb8\x3c\x00\x00\x00\xbf\x00\x00\x00\x00\x0f\x05" #Create buffer in memory shellcode_buffer = ctypes.create_string_buffer(shellcode, len(shellcode)) #Funktionszeiger shellcode_func = ctypes.cast(shellcode_buffer, ctypes.CFUNCTYPE(ctypes.c_void_p)) #Shellcode execute shellcode_func() If i run python Scriptname.py I get a memory

I am trying to make some basic system calls in assembly (x86-64 in NASM on OSX), but have so far been unsuccessful. The only examples I have seen on the web so far are for reading from stdin or writing to stdout, such as this: global main section .text main: call write write: mov rax, 0x2000004 mov rdi, 1 mov rsi, message mov rdx, length syscall section .data message: db 'Hello, world!', 0xa length: equ $ - message However, when I try to use that same pattern to make another system call, it doesn't work (it's saying Bus error: 10 ): global main section .text main: call mkdir mkdir: mov rax,

I try to install pyaudio in pycharm, and I get this error error: command 'C:\\Program Files (x86)\\Microsoft Visual Studio 14.0\\VC\\BIN\\cl.exe' failed with exit status 2 I used pip install pyaudio command. Copy comment: I downloaded PyAudio‑0.2.11‑cp37‑cp37m‑win_amd64.whl try to install it using this command pip install PyAudio‑0.2.11‑cp37‑cp37m‑win_amd64 but it does not work and get this error ERROR: Could not find a version that satisfies the requirement PyAudio-0.2.11-cp37-cp37m-win_amd64 (from versions: none) ERROR: No matching distribution found for PyAudio-0.2.11-cp37-cp37m-win_amd64

I'm having trouble figuring out how to use printf correctly in this function. So the function is called multInts and is supposed to multiply the first element of the first array with the first element of the second array and continue through the whole array. However, the lab instructions specify that I can't call printf in the main function. So, I need to print out the word "Products:\n" and then in each new line after that, print out the product. I don't know how to use printf within the loop, however. The instructor said that we should "call printf in the loop after calculating product" and

I found an example and was editing it for gas. extern printf .global _start .data hello: db "Hello", 0xa, 0 .text _start: mov %rdi, hello mov %rax, 0 call printf mov %rax, 0 ret But it doesn't work. What's wrong? What does this mean: hello: db "Hello", 0xa, 0 I understand what it scope of memory, but I don't understand this string db "Hello", 0xa, 0 And here _start: mov %rdi, hello mov %rax, 0 call printf mov %rax, 0 ret os: linux (debian). intel 64-bit It's is the null-byte-terminattor . Well-know as C-string.Such byte at end-of-string say where the string ends. For example,you pass the