Mark's Magic Multiply

 (wren.wtf)

47 points | by luu 1 day ago

3 comments

  • awjlogan 10 hours ago
    Link to Mark Owen’s excellent QFP library for soft float on Cortex-M0+ (ARMv6-M) and Cortex-M3/M4 (ARMv7-M).

    https://www.quinapalus.com/qfplib.html

    Nice write up here, too, I like the idea of a firm float.

  • NooneAtAll3 1 hour ago
    Since the trick works on mantissa only without hidden 1 included, I wonder if that number of bits in mantissa was chosen because of it
  • mysterydip 7 hours ago
    I appreciate this warning near the top: This post contains floating point. Floating point is known to the State of California to cause confusion and a fear response in mammalian bipeds.

    I wisely hit the back button :)

    [-]
    • bombcar 3 hours ago
      I saw an explanation (perhaps Fabien's) which made it click - floating point is just segment:offset addressing for numbers!

      Then the full horror of it hit me.