import struct
import matplotlib.pyplot as plt

struct_fmt = '<H' # int[5], float, byte[255]
struct_len = struct.calcsize(struct_fmt)
struct_unpack = struct.Struct(struct_fmt).unpack_from

samp = []    
with open("C:\\Users\\William\\Downloads\\test.u16", "rb") as f:
    while True:
        data = f.read(struct_len)
        if not data: break
        s = struct_unpack(data)
        samp.append(s[0])

def dactolin(dacval):
    mantissa = ((dacval & 0x1FF8) >> 3)
    exponent = (~(dacval >> 13) & 7)
    return (mantissa << 6) >> exponent
    
def better_dactolin(dacval):
    mantissa = (dacval >> 3)  & 0b111111111
    sign     = (dacval >> 12) & 0b1
    exponent = (dacval >> 13) & 0b111
    high_bits = 0b0000000_000000000 if sign else 0b0111111_000000000
    high_mant = high_bits | mantissa
    sample   = (sign << 15) | ((high_mant << (exponent - 1)) & 0x7fff)
    return sample

lin_samp = []
for s in samp:
    lin_samp.append(better_dactolin(s))

_ = plt.plot(lin_samp[0:10000], '-.')