New Cog VMs
Eliot Miranda has released new Cog VMs - I'm quoting an email to the Squeak list below:
I've released a new version of Cog that has a substantially improved code generator along the lines of Peter Deutsch's HPS (VisualWorks) and various of Ian Piumarta's VMs. These all use a simple tecnique to identify constant references in bytecode and to support a register-based calling convention. While this does produce faster code it tends to accelerate low-level code much more than high-level code
You can download them here - and follow Eliot on his blog here.