'as' dcmd for Mac

From Balance Software, Inc.:

The 'as' dcmd is a PowerPC assembler (which includes the AltiVec instruction set) plugin for MacsBug (Apple's low-level debugger). The assembler may be used either as an informational tool for the programmer who wishes to know what a particular instruction would assemble to, or as a debugging aid with which the programmer may assemble to memory locations on-the-fly. This allows the programmer to repair a bit of faulty code while debugging without the need for a time-consuming cycle of quitting the application (potentially causing a crash), recompiling, and re-running the program.