How to Resolve ERROR_NOACCESS (0x3E6) When Injecting Assembly Code into a PE File Using CreateThread

I encountered an issue when injecting my assembly program **asm.txt** into a **portable executable file** to run a keylogger using `CreateThread`. `CreateThread` was failing with the error code `0x3E6 (ERROR_NOACCESS)`. […]

What Are the Architectural Constraints in Haswell That Limit CPE Optimization?

I want to understand why any scalar version of the inner product procedure cannot achieve a CPE less than `1.00` on an Intel Core i7 4790 Haswell processor, Ubuntu 20.04 […]

Unexpected Memory Value Fluctuations in GDB While Debugging Pointer in x86-64 C Program

In my last question, I misunderstood how GDB interprets memory when using different formats like `x/d` and `x/1wd`. After some digging, I realized the issue was related to GDB displaying […]

Understanding cmp Instruction in Assembly and Debugging with GDB

I’ve come across a specific instruction sequence that I need help understanding, particularly the comparison (`cmp`) operation and how to break at this point in GDB on an Intel Core […]

Can I Directly Update the TLB During a Page Fault on x86-64?

I’m working with x86-64 architecture in long mode and want to know if it’s possible to directly update the Translation Lookaside Buffer (TLB) with a mapping from a virtual address […]

Issues with 64-bit DLL Injection Shellcode on OpenBSD Ignoring Integer Pushes

I want to inject a 64 bit DLL into a 64 bit process on OpenBSD. The shellcode needs to push several 64 bit values onto the stack, including the old […]

How to optimize SIMD instructions for double precision floating point operations on Intel Core i7

I want to optimize a computationally intensive loop using SIMD instructions on an Intel Core i7 `12700K` processor and 32GB of DDR4 `3200` memory , to boost the performance for […]

Optimizing a bubble sort implementation in C for an x86-64 architecture

Hello , I’m working on optimizing a bubble sort implementation in `C` for an `x86-64` architecture specifically targeting an Intel Core i7 processor using `GCC 11.2` . I noticed that […]

Debugging Persistent Segmentation Fault in Multi-threaded C++ Program on AMD Barcelona CPUs

I have been wrestling with a persistent segmentation fault in a multi-threaded C++ program running on a cluster of AMD Barcelona CPUs Linux/x86_64. The code causing the crashes is a […]