High Level Assembler or HLASM is IBM's current assembler product for its z/OS, z/VSE, z/VM and z/TPF operating systems on z/Architecture mainframe computers. There is also a version that runs on Linux, primarily intended for systems running on a z/Architecture system (this environment is sometimes referred to as z/Linux).
HLASM was introduced in 1992 replacing IBM's H assembler.
Despite the name HLASM on its own does not have many of the features normally associated with a high-level assembler, but does offer a number of improvements over Assembler H and Assembler(XF), such as labeled and dependent USINGs, more complete cross-reference information, and additional macro language capabilities such as the ability to write user-defined functions.
The High Level Assembler Toolkit is a separately priced accompaniment to the High Level Assembler. The toolkit contains: