AbstractVirtual machines (VMs) facilitate the deployment of applications in heterogeneous environments. Popular VMs such as Sun Microsystem's Java VM or Microsoft's Common Language Runtime (CLR) use a stack-based machine architecture to execute bytecode instructions. The focus of this paper is to explore the ability of XML to serve as a generic framework to represent bytecode instructions from different VMs. With an XML representation, supporting technologies such as XSL stylesheets and XPath expressions can be used to provide various transformations of bytecode instructions. We demonstrate the flexibility and power of this approach by showing examples of cross-compilation for various CLR bytecode instructions to the JVM as well as API mappings of the underlying runtime libraries.