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LibCrypto: Fix subtracting two negative SignedBigInteger
s
Currently, we get the following results
-1 - -2 = -1
-2 - -1 = 1
Correct would be:
-1 - -2 = 1
-2 - -1 = -1
This was already attempted to be fixed in 7ed8970
, but that change was
incorrect. This directly translates to LibJS BigInts having the same
incorrect behavior - it even was tested.
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parent
014840eeca
commit
58c6a156bf
3 changed files with 17 additions and 4 deletions
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@ -109,11 +109,15 @@ FLATTEN SignedBigInteger SignedBigInteger::minus(const SignedBigInteger& other)
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// -x - -y = y - x
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if (m_unsigned_data < other.m_unsigned_data) {
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// The result will be positive.
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return SignedBigInteger { other.m_unsigned_data.minus(m_unsigned_data), true };
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return SignedBigInteger { other.m_unsigned_data.minus(m_unsigned_data) };
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}
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// The result will be either zero, or negative.
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// y - x = - (x - y)
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return SignedBigInteger { m_unsigned_data.minus(other.m_unsigned_data) };
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if (m_unsigned_data > other.m_unsigned_data) {
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// The result will be negative.
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return SignedBigInteger { m_unsigned_data.minus(other.m_unsigned_data), true };
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}
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// Both operands have the same magnitude, the result is positive zero.
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return SignedBigInteger { 0 };
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}
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FLATTEN SignedBigInteger SignedBigInteger::plus(const UnsignedBigInteger& other) const
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