Asm48 is a cross assembler for the ubiquitous Intel(tm) 8048 family of microcontrollers. The assembler is at an early stage of development. However, the major functionality is in place, and with some testing it will be considered stable very soon. If you feel slightly adventurous and don't mind fixing some bugs, you could probably use Asm48 right now.
You can check out the latest version of the source code using CVS from the SourceForge project page. Click on the "CVS Repository" link at the bottom of the page, and follow the directions for Anonymous CVS Access. Use "asm48" as modulename.
You can also browse the CVS repository.
The latest source is also available in the multi-platform ZIP package for version 0.4.1 that you'll find in the files area.
Asm48 is written in standard C, and uses flex and bison. You also will need GNU Make (although the Makefile could easily be modified for other make variants). Most Unix-like systems (such as Linux and FreeBSD) and Windows machines running Cygwin should be able to build Asm48. See the README for more information on how to build.
Please send bug reports, flames, etc. to firstname.lastname@example.org.