double offset = pow(2, (i >> 20) - 0x3ff) * (((i & 0xfffff) + 0x100000) / (double) 0x100000);

>>> def IntFromReal32(i):
        exponent = (i >> 20) - 0x3ff
        mantissa = (i & 0xfffff) + 0x100000
        return mantissa >> (20 - exponent)

>>> testdata = range(0x40000000,0x40240000,0x10000) + range(0x40800000,0x40830000,0x10000) + [1088631936]
>>> from datetime import date,timedelta
>>> for i in testdata:
        print "0x%08x" % i, date(1899,12,30) + timedelta(IntFromReal32(i))


0x40000000 1900-01-01
0x40010000 1900-01-01
0x40020000 1900-01-01
0x40030000 1900-01-01
0x40040000 1900-01-01
0x40050000 1900-01-01
0x40060000 1900-01-01
0x40070000 1900-01-01
0x40080000 1900-01-02
0x40090000 1900-01-02
0x400a0000 1900-01-02
0x400b0000 1900-01-02
0x400c0000 1900-01-02
0x400d0000 1900-01-02
0x400e0000 1900-01-02
0x400f0000 1900-01-02
0x40100000 1900-01-03
0x40110000 1900-01-03
0x40120000 1900-01-03
0x40130000 1900-01-03
0x40140000 1900-01-04
0x40150000 1900-01-04
0x40160000 1900-01-04
0x40170000 1900-01-04
0x40180000 1900-01-05
0x40190000 1900-01-05
0x401a0000 1900-01-05
0x401b0000 1900-01-05
0x401c0000 1900-01-06
0x401d0000 1900-01-06
0x401e0000 1900-01-06
0x401f0000 1900-01-06
0x40200000 1900-01-07
0x40210000 1900-01-07
0x40220000 1900-01-08
0x40230000 1900-01-08
0x40800000 1901-05-26
0x40810000 1901-06-27
0x40820000 1901-07-29
0x40e33480 2007-09-07

In [8]: time.strftime("%s", (2009, 3, 21, 1, 1, 0, 0,0,0))
Out[8]: '1237590060'

In [9]: time.strftime("%s", (2009, 3, 22, 1, 1, 0, 0,0,0))
Out[9]: '1237676460'

In [10]: print("%0x %0x" % (1237590060, 1237676460))
49c4202c 49c571ac

date     time       abw     xtr   dbcap   avabw   avxtr  avdbcap      rtt    timestamp
06/30/04 14:43:48  1.000   0.000   1.100   1.042   0.003    1.095  384.387   1088631828
06/30/04 14:45:36  1.100   0.000   1.100   1.051   0.003    1.096  376.408   1088631936
06/30/04 14:47:23  1.000   0.000   1.100   1.043   0.003    1.097  375.196   1088632043