Fmt.Big.sub: def of bend-kit-fmt@0.1.0.0
Import: import bend-kit-fmt@0.1.0.0/fmt.bend as Fmt
Lines 150-157 of bend-kit-fmt@0.1.0.0/fmt.bend: https://jend.leeeet.dev/read.txt?path=bend-kit-fmt@0.1.0.0/fmt.bend&start_line=150&end_line=157

import Base

# a - b for a >= b; w is the borrow.
def Big.sub(a: List<&2, U32>, b: List<&2, U32>, w: U32) -> List<&2, U32>:
  match a b:
    case Con{x, xs} Con{y, ys}:
      +t = {U32.sub(U32.sub(U32.add(x, 65536), y), w) : U32}
      Con{U32.and(t, 65535), Big.sub(xs, ys, U32.sub(1, U32.shrn(t, 16n)))}
    case _ _:
      Nil{}

Uses (6):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.add
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.and
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.shrn
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.sub