Glazer is an assembler for the Glulx VM, and version 1.2.0 is now available here:
The changes since 1.1.0 are mainly concerned with the usage of labels, especially allowing the full range of math operations on them.
I have also been working on support for the Z-machine. However it was not ready for this release (by a long way), and will probably take a while before it becomes usable, as it’s not a big priority for me (just something to hack on now and then).