Node: ESA/390 Notes, Next: ESA/390 Options, Up: ESA/390-Dependent

### Notes

The ESA/390 `as` port is currently intended to be a back-end for the GNU CC compiler. It is not HLASM compatible, although it does support a subset of some of the HLASM directives. The only supported binary file format is ELF; none of the usual MVS/VM/OE/USS object file formats, such as ESD or XSD, are supported.

When used with the GNU CC compiler, the ESA/390 `as` will produce correct, fully relocated, functional binaries, and has been used to compile and execute large projects. However, many aspects should still be considered experimental; these include shared library support, dynamically loadable objects, and any relocation other than the 31-bit relocation.