1-bit architecture

Bit
1 4 8 12 16 18 24 26 31 32 36 48 60 64 128 256 512
Application
16 32 64
Floating point precision
×½ ×1 ×2 ×4 ×8
Floating point decimal precision
32 64 128

1-bit microprocessor MC14500BCP

A 1-bit computer architecture is an instruction set architecture for a processor that has datapath widths and data register widths of 1 bit (1/8 octet) wide.

An example of a 1-bit architecture that was actually marketed as a CPU is the Motorola MC14500B Industrial Control Unit.^[1] There are also several design studies for 1-bit architectures in academia, and corresponding 1-bit logic can also be found in programming.

Other examples of 1-bit architectures are programmable logic controllers.

A typical sequence of instructions from a program for a 1-bit architecture might be:

• load digital input 1 into a 1-bit register;
• OR the value in the 1-bit register with input 2, leaving the result in the register;
• write the value in the 1-bit register to output 1.

1-bit CPUs can be considered obsolete now, not many kinds have been produced (MC14500B and WDR-1 known) and none known to be available in the major computer component stores (as of 2014, a few on eBay^[2]). Finnish company Partco still sells MC14500B [compatible] as spare part in 2016.^[3]

See also

• Bit slicing

References

1. "MC14500B Industrial Control Unit. Semiconductor Technical Data, Rev. 3" (PDF). Motorola. 1995. Retrieved August 1, 2012.
2. http://www.ebay.com/itm/Motorola-IC-MC14500B-MC14500BCL-100-NEW-/320837692605
3. "CMOS-LOGIC IC 4500 DIP16". Also known as MC14500BCP

External links

• WDR-1-Bit Computer