test/float_lit2: Wrong exponent in comment.

[cznic]

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tip @ 0cff219

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test/float_lit2:21 reads

// The halfway point is (f₁+f₂)/2 = 2¹²⁸ - 2¹⁰⁵.

The expression should be 2^128-2^103, ie. s/105/103/ above.

If approved, I can send a CL later today.

[bradfitz]

/cc @griesemer

[griesemer]

I think there are other mistakes in this comment as well. The largest float32 exponent is 127, thus the largest float32 is maxMant * 2**127. maxMant is 1 (implicit) + (2**23 -1)/(2**23) == 1 + 1 - 1/(2**23). Together we have maxFloat32 == (1 + 1 - 1/(2**23)) * 2**127 == (2 - 2**-23) * 2**127 == 2**128 - 2**104 == f1 (first line).

With f2 == 2**128, f1 + f2 == 2**128 - 2**104 + 2**128 == 2**129 - 2**104. Thus (f1 + f2)/2 == 2**128 - 2**103, as you suggest.

Feel free to send me a CL and assign it to me for review. Thanks.

[gopherbot]

CL https://golang.org/cl/29171 mentions this issue.