[vcpkg] Correct UInt128 code 😇#10583
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strega-nil merged 4 commits intomicrosoft:masterfrom Apr 9, 2020
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`UInt128::operator<<(x, y)` should clear the bottom 64 bits of `x` if `y >= 64`; however, we don't do this, and so we duplicate `x`'s bottom bits into `x.top` instead of moving them. Similarly, we have the opposite problem for `UInt128::operator>>`. This commit fixes these latent bugs, which we weren't hitting because the thing we use them for never actually shifts more than 64 bits.
RobertHenry6bev
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Mar 27, 2020
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I would write some unit tests too.
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Oof, getting 504s from github when trying to download the code... |
BillyONeal
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Apr 9, 2020
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* [vcpkg] Correct UInt128 code 😇 `UInt128::operator<<(x, y)` should clear the bottom 64 bits of `x` if `y >= 64`; however, we don't do this, and so we duplicate `x`'s bottom bits into `x.top` instead of moving them. Similarly, we have the opposite problem for `UInt128::operator>>`. This commit fixes these latent bugs, which we weren't hitting because the thing we use them for never actually shifts more than 64 bits.
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UInt128::operator<<(x, y)should clear the bottom 64 bits ofxify >= 64; however, we don't do this, and so we duplicatex's bottombits into
x.topinstead of moving them. Similarly, we have theopposite problem for
UInt128::operator>>. This commit fixes theselatent bugs, which we weren't hitting because the thing we use them for
never actually shifts more than 64 bits.
Fixes #10582 :)