There has been a lot of work on writing JVMs in general , on JVMs for 64-bit RISC , and JVMs for x86 in particular . Many of these JVMs are not well documented in the research literature because of competitive concerns. Two notable exceptions are IBM's Jalapeño JVM and Intel's Open Research Platform(ORP). IBM's JVM is similar to ours in that it started out life as a RISC JVM on PowerPC, and has recently been ported to x86 . Intel's JVM is of course native to the x86, but may experience similar porting pains when moving the IA64.  describes the architecture of the HotSpot Virtual Machine.  describes the FastVM for Alpha that we ported to x86. In addition to just-in-time compilers several static compilers exist that generate native code from Java source code and use standard compiler backends for optimization [16,4,20] Unlike much of the published literature on x86 JVMs, our work focuses on the gritty, low-level design considerations required to make a JVM use a CISC instruction set effectively.