4 ms·

From the paper: > Finding Turing-completeness in unlikely places has long been a pastime of bored computer scientists. The number of bizarre ma- chines that ha

by tekacs 13y ago

From the paper: > Finding Turing-completeness in unlikely places has long been a pastime of bored computer scientists. The number of bizarre ma- chines that have been shown Turing-complete is far too great to describe them here, but a few resemble what this paper describes. > ... [several examples] ... > A single instruction machine using only MOVE was described by Douglas W. Jones [1], where Turing-completeness is gained by having memory-mapped arithmetic and logic units (so that other operations can be performed by moving data a predefined memory location and collecting the result afterwards). Some machines based on this principle have been built, and are generally known as “move machines” or “transport-triggered architectures”. Also: > Removing all but the mov instruction from future iterations of the x86 architecture would have many advantages: the instruction format would be greatly simplified, the expensive decode unit would become much cheaper, and silicon currently used for complex functional units could be repurposed as even more cache. As long as someone else implements the compiler. :)

ibrahima 13y ago
> > Removing all but the mov instruction from future iterations of the x86 architecture would have many advantages: the instruction format would be greatly simplified, the expensive decode unit would become much cheaper, and silicon currently used for complex functional units could be repurposed as even more cache. As long as someone else implements the compiler. I realize it's tongue in cheek, but saying the decode unit in x86 is expensive is kind of a tired and untrue adage in today's computer architecture terms. But I guess it is fair to say that the die is stuffed with as much cache as they can fit :)
- duaneb 13y ago
  It may not be accurate to say "decode unit" anymore but who wouldn't welcome anything removing the large amounts of cruft from the ISA? Nobody uses most of the damn opcode space except where required for mode trickery or legacy code.

by tekacs 13y ago

ibrahima 13y ago

> > Removing all but the mov instruction from future iterations of the x86 architecture would have many advantages: the instruction format would be greatly simplified, the expensive decode unit would become much cheaper, and silicon currently used for complex functional units could be repurposed as even more cache. As long as someone else implements the compiler. I realize it's tongue in cheek, but saying the decode unit in x86 is expensive is kind of a tired and untrue adage in today's computer architecture terms. But I guess it is fair to say that the die is stuffed with as much cache as they can fit :)

duaneb 13y ago
It may not be accurate to say "decode unit" anymore but who wouldn't welcome anything removing the large amounts of cruft from the ISA? Nobody uses most of the damn opcode space except where required for mode trickery or legacy code.