Did anyone try dynamic recompilation from x86 to x86? Like a JIT taking advantage of the fact that the target ISA is compatible with with the source ISA.
Yes, I think the conclusion was that it did improve performance on binaries that were not compiled with optimizations, but didn't generate enough gains on optimized binaries to set of the cost of re-compilation.
I believe it was HP who accidentally tried this while making an early equivalent of Rosetta to deal with a hardware change on their mainframes and mini computers. They modified it to run same-same translations and they did get notable performance improvements by doing so.
I’m pretty sure this experiment happened before Transmeta existed, or when it was still forming. So it ended up being evidence that what they were doing might work. It also was evidence that Java wasn’t completely insane to exist.
The Dynamo project was the genesis of a similar effort at Sun Microsystems which was the genesis of Transmeta Corp (all founders came from Sun). The question remains if the original study was flawed or if the situation was just too different for our x86 workloads.
Notably VMware and alike in pre-hardware virtualization era did something like that to run x86 programs fast under virtualization instead of interpreting x86 through emulation.
