The point of test %eax %eax [duplicate]

This question already has answers here: Closed 9 years ago. Possible Duplicate: x86 Assembly – ‘testl’ eax against eax? I’m very very new to assembly language programming, and I’m currently trying to read the assembly language generated from a binary. I’ve run across test %eax,%eax or test %rdi, %rdi, etc. etc. I’m very confused as … Read more

What is exactly the base pointer and stack pointer? To what do they point?

Using this example coming from wikipedia, in which DrawSquare() calls DrawLine(), (Note that this diagram has high addresses at the bottom and low addresses at the top.) Could anyone explain me what ebp and esp are in this context? From what I see, I’d say the stack pointer points always to the top of the … Read more

What is a retpoline and how does it work?

In order to mitigate against kernel or cross-process memory disclosure (the Spectre attack), the Linux kernel1 will be compiled with a new option, -mindirect-branch=thunk-extern introduced to gcc to perform indirect calls through a so-called retpoline. This appears to be a newly invented term as a Google search turns up only very recent use (generally all … Read more

How to compile Tensorflow with SSE4.2 and AVX instructions?

This is the message received from running a script to check if Tensorflow is working: I tensorflow/stream_executor/dso_loader.cc:125] successfully opened CUDA library libcublas.so.8.0 locally I tensorflow/stream_executor/dso_loader.cc:125] successfully opened CUDA library libcudnn.so.5 locally I tensorflow/stream_executor/dso_loader.cc:125] successfully opened CUDA library libcufft.so.8.0 locally I tensorflow/stream_executor/dso_loader.cc:125] successfully opened CUDA library libcuda.so.1 locally I tensorflow/stream_executor/dso_loader.cc:125] successfully opened CUDA library libcurand.so.8.0 locally … Read more

Deoptimizing a program for the pipeline in Intel Sandybridge-family CPUs

I’ve been racking my brain for a week trying to complete this assignment and I’m hoping someone here can lead me toward the right path. Let me start with the instructor’s instructions: Your assignment is the opposite of our first lab assignment, which was to optimize a prime number program. Your purpose in this assignment … Read more