Programming tools typically output hexfile.

These languages often come as part of an integrated develoment environment (IDE), bundled together with an editor (possibly with syntax highlight) and various debugging tools (usually a software simulator, monitor "GUI" and/or emulator (ICE) GUI.

However, today there are also quite a couple of general IDEs around (e.g. UltraEdit, se), allowing to quickly integrate whatever tools you have for '51 programming and debugging on different platforms.