You could have downloaded HSW12 1.0 for Mac from our application library for free. Hsw12-master.zip is the frequent file name to indicate this application's installer. The following version: 1.0 was the most frequently downloaded one by the program users. This free application works fine with Mac OS X 10.4 or later. This free Mac application is an intellectual property of Dirk Heisswolf. HSW12 for Mac relates to Developer Tools.
From the developer:
HSW12 is an assembler and debug environment for Freescale's HC11, HC12, HCS12, and HCS12X microcontroller families. The HSW12 GUI is split up into several windows to give you the freedom to place its components anywhere on the screen. It is written in Perl/Tk and provides an interface to the D-BUG12 POD. It comes with its own assembler which has been written in Perl as well.
You may want to check out more software for Mac, such as PowerGlot, ChIDE or flex sdk 3, which might be related to HSW12.