Wang Labs made an amazing (for its time) calculator, the LOCI-1, quickly replaced by the much more capable LOCI-2. They were from 1964/1965 and were built with

Wang Labs made an amazing (for its time) calculator, the LOCI-1, quickly replaced by the much more capable LOCI-2. They were from 1964/1965 and were built with core memory and discrete transistors, 1200 of them, no ICs. It operated with 10 digits of precision, and its native hardware could add and subtract. Rather than doing multiplication and division and square root directly, instead the calculator was able to compute logs and antilogs via successive addition and subtraction. Multiplying two numbers might return 199.9999999 instead of 200.0, but since this was built for engineers who were mathematically literate, it was acceptable. There were other calculators that could be programmed to compute logs and antilogs, but they were slow. On the LOCI machines, the results were instant (on a human timescale). Description of the LOCI-2: https://www.oldcalculatormuseum.com/wangloci.html https://www.oldcalculatormuseum.com/wangloci.html Just found this description of the log algorithm -- it used only six constants in its iterative add/subtract/shift algorithm to compute logs and antilogs: https://osgalleries.org/journal/pdf_files/20.2/V20.2P51.pdf https://osgalleries.org/journal/pdf_files/20.2/V20.2P51.pdf