Bit slicing

Bit slicing is a technique for constructing a processor from modules of processors of smaller bit width, for the purpose of increasing the word length; in theory to make an arbitrary n-bit central processing unit (CPU).

Recently it has been used in arithmetic logic units (ALUs) for quantum computers and as a software technique, e.g. for cryptography in x86 CPUs.

Prior to the mid-1970s and late 1980s there was some debate over how much bus width was necessary in a given computer system to make it function.

In more recent times, the term bit slicing was reused by Matthew Kwan[17] to refer to the technique of using a general-purpose CPU to implement multiple parallel simple virtual machines using general logic instructions to perform single-instruction multiple-data (SIMD) operations.

To simplify the circuit structure and reduce the hardware cost of quantum computers (proposed to run the MIPS32 instruction set) a 50 GHz superconducting "4-bit bit-slice arithmetic logic unit (ALU) for 32-bit rapid single-flux-quantum microprocessors was demonstrated".