Posted by RoarCade on 13, 2001 at 10:34 AM:
I recently bought (I am after all a Gadget-man) a Sony Vaio Picturebook. Besides being an awesome piece of technology, in its size and abilities, through investigation of it's operations and design I found out something rather remarkable. It's actually a RISC-type processor that EMULATES an x86 processor. They call it a "Software layer" and also "Code Morphing" a whole slew of terms that boil down to one basic concept, Acceptable, mass-marketed, sold, authorized EMULATION.
Check it out:
Crusoe Processor Technology
Transmeta has pioneered a revolutionary new approach to microprocessor design. Rather than implementing the entire x86 processor in hardware, the Crusoe processor solution consists of a compact hardware engine surrounded by a software layer.
The hardware component is a very simple, high-performance, low-power VLIW (Very Long Instruction Word) engine with an instruction set that bears no resemblance to that of x86 processors. Instead, it is the surrounding software layer that gives programs the impression that they are running on x86 hardware. This innovative software layer is called the Code Morphing software because it dynamically "morphs" (that is, translates) x86 instructions into the hardware engine's native instruction set.
Transmeta's software translates blocks of x86 instructions once, saving the resulting translation in a translation cache. The next time the (now translated) code is executed, the system skips the translation step and directly executes the existing optimized translation at full speed.
This unique approach to executing x86 code eliminates millions of transistors, replacing them with software. The current implementation of the Crusoe processor uses roughly one-quarter of the logic transistors required for an all-hardware design of similar performance. This offers the following benefits:
The hardware component is considerably smaller, faster, and more power efficient than conventional chips.
The hardware is fully decoupled from the x86 instruction set architecture, enabling Transmeta's engineers to take advantage of the latest and best in hardware design trends without affecting legacy software.
The Code Morphing software can evolve separately from hardware. This means that upgrades to the software portion of the microprocessor can be rolled out independently of hardware chip revisions.
Transmeta's Code Morphing technology is obviously not limited to x86 implementations. As such, it has the potential to revolutionize the way microprocessors are designed in the future.
For more details on how translation software and the Crusoe hardware engine work in concert, see our whitepaper, The Technology Behind Crusoe(TM) Processors (pdf)*.