at&t syntax utilization example

When talking about pointers, we generally assume it is something that can be represented by void* pointer which has a size of 8 bytes on the x86_64 architecture.

Frequently executed functions in applications are some times built into many versions to take advantage of specific support or features of the hardware that executes the application. For example, functions are compiled to use SSE4 instructions if the hardware supports it. There is, however, the developer burden of creating the dispatching mechanism to execute the right version at runtime . This aim of this project is to make it really easy for the developer to specify multiple versions of a function, each catered to a specific target ISA feature. GCC then takes care of creating the dispatching code necessary to execute the right function version. With this support, here is a simple example of how to create function versions:

GCC recently (version 4.9) gained Undefined Behavior Sanitizer (ubsan), a run-time checker for the C and C++ languages. In order to check your program with ubsan, compile and link the program with -fsanitize=undefined option. Such instrumented binaries have to be executed; if ubsan detects any problem, it outputs a “runtime error:” message, and in most cases continues executing the program.

The idea of transactional memory is to create a block of a code that will be executed 'atomically'. Thanks to this abstraction, the creation of a concurent program is a bit easier. Indeed, it avoids the usage of locks to protect a shared data-structure or variable. This block delimits the start and the commit of the transaction.

compile c/c++ code in assembly with an broswer