src/nmutil/util.py

   1 from collections.abc import Iterable
   2 from nmigen import Mux
   3
   4 # XXX this already exists in nmigen._utils
   5 # see https://bugs.libre-soc.org/show_bug.cgi?id=297
   6 def flatten(v):
   7     if isinstance(v, Iterable):
   8         for i in v:
   9             yield from flatten(i)
  10     else:
  11         yield v
  12
  13 # tree reduction function.  operates recursively.
  14 def treereduce(tree, op, fn):
  15     """treereduce: apply a map-reduce to a list.
  16     examples: OR-reduction of one member of a list of Records down to a
  17               single data point:
  18               treereduce(tree, operator.or_, lambda x: getattr(x, "data_o"))
  19     """
  20     #print ("treereduce", tree)
  21     if not isinstance(tree, list):
  22         return tree
  23     if len(tree) == 1:
  24         return fn(tree[0])
  25     if len(tree) == 2:
  26         return op(fn(tree[0]), fn(tree[1]))
  27     s = len(tree) // 2 # splitpoint
  28     return op(treereduce(tree[:s], op, fn),
  29               treereduce(tree[s:], op, fn))
  30
  31 # chooses assignment of 32 bit or full 64 bit depending on is_32bit
  32 def eq32(is_32bit, dest, src):
  33     return [dest[0:32].eq(src[0:32]),
  34             dest[32:64].eq(Mux(is_32bit, 0, src[32:64]))]
  35
  36