Help needed!

[soarowl]

I have little snippet:

import binarylang

struct(i7, endian = l, bitEndian = r):
  u1:
    flag = 0
  7:
    value

block:
  var sbs = newStringBitStream()
  for v in -10 .. 10:
    sbs.seek(0)
    let data = I7(value: v.int8)
    i7.put(sbs, data)
    sbs.seek(0)
    let data2 = i7.get(sbs)
    echo data2
    doAssert data.value == data2.value

When I put -1, but get 127 back, so assert fail. I dont know why. Help me, please!