We will now scratch the surface of writing PTX (Parallel Thread eXecution) Assembly language, which is a kind of a pseudo-assembly language that works across all Nvidia GPUs, which is, in turn, compiled by a Just-In-Time (JIT) compiler to the specific GPU's actual machine code. While this obviously isn't intended for day-to-day usage, it will let us work at an even a lower level than C if necessary. One particular use case is that you can easily disassemble a CUDA binary file (a host-side executable/library or a CUDA .cubin binary) and inspect its PTX code if no source code is otherwise available. This can be done with the cuobjdump.exe -ptx cuda_binary command in both Windows and Linux.
As stated previously, we will only cover some of the basic usages of PTX from within CUDA-C, which has a particular syntax and usage which is similar to that of...