PTX

The ISA to which CUDA's nvcc compiles source code. This is JIT'd into architecture-specific machine language by the hardware driver after the CUDA runtime is used to load a PTX module. It can then be scheduled for execution on CUDA devices. From Version 2.1 of the PTX ISA Reference:

PTX defines a virtual machine and ISA for general purpose parallel thread execution. PTX programs are translated at install time to the target hardware instruction set. The PTX-to-GPU translator and driver enable NVIDIA GPUs to be used as programmable parallel computers.

Versions

PTX Version	CUDA Toolkit Version	Changes
2.1	3.1	Stack-based API, indirect branches and function pointers for sm_2x targets .branchtargets, .calltargets, and .callprototype directives 32 driver-specific execution environment registers %envreg0..%envreg31 New instruction rcp.approx.ftz.f64 for fast approximate reciprocal
2.0	3.0

Tools

• Marcin Wilhelm Kościelnicki's nv50dis, a disassembler