diff -r 000000000000 -r 6474c204b198 mfbt/decimal/floor-ceiling.patch
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mfbt/decimal/floor-ceiling.patch	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,89 @@
+diff --git a/mfbt/decimal/Decimal.cpp b/mfbt/decimal/Decimal.cpp
+--- a/mfbt/decimal/Decimal.cpp
++++ b/mfbt/decimal/Decimal.cpp
+@@ -618,26 +618,26 @@ Decimal::AlignedOperands Decimal::alignO
+ Decimal Decimal::ceiling() const
+ {
+     if (isSpecial())
+         return *this;
+ 
+     if (exponent() >= 0)
+         return *this;
+ 
+-    uint64_t result = m_data.coefficient();
+-    const int numberOfDigits = countDigits(result);
++    uint64_t coefficient = m_data.coefficient();
++    const int numberOfDigits = countDigits(coefficient);
+     const int numberOfDropDigits = -exponent();
+     if (numberOfDigits < numberOfDropDigits)
+         return isPositive() ? Decimal(1) : zero(Positive);
+ 
+-    result = scaleDown(result, numberOfDropDigits - 1);
+-    if (sign() == Positive && result % 10 > 0)
+-        result += 10;
+-    result /= 10;
++    uint64_t result = scaleDown(coefficient, numberOfDropDigits);
++    uint64_t droppedDigits = coefficient - scaleUp(result, numberOfDropDigits);
++    if (droppedDigits && isPositive())
++        result += 1;
+     return Decimal(sign(), 0, result);
+ }
+ 
+ Decimal Decimal::compareTo(const Decimal& rhs) const
+ {
+     const Decimal result(*this - rhs);
+     switch (result.m_data.formatClass()) {
+     case EncodedData::ClassInfinity:
+@@ -660,26 +660,27 @@ Decimal Decimal::compareTo(const Decimal
+ Decimal Decimal::floor() const
+ {
+     if (isSpecial())
+         return *this;
+ 
+     if (exponent() >= 0)
+         return *this;
+ 
+-    uint64_t result = m_data.coefficient();
+-    const int numberOfDigits = countDigits(result);
++    uint64_t coefficient = m_data.coefficient();
++    const int numberOfDigits = countDigits(coefficient);
+     const int numberOfDropDigits = -exponent();
+     if (numberOfDigits < numberOfDropDigits)
+         return isPositive() ? zero(Positive) : Decimal(-1);
+ 
+-    result = scaleDown(result, numberOfDropDigits - 1);
+-    if (isNegative() && result % 10 > 0)
+-        result += 10;
+-    result /= 10;
++    uint64_t result = scaleDown(coefficient, numberOfDropDigits);
++    uint64_t droppedDigits = coefficient - scaleUp(result, numberOfDropDigits);
++    if (droppedDigits && isNegative()) {
++        result += 1;
++    }
+     return Decimal(sign(), 0, result);
+ }
+ 
+ Decimal Decimal::fromDouble(double doubleValue)
+ {
+     if (std::isfinite(doubleValue))
+         return fromString(String::numberToStringECMAScript(doubleValue));
+ 
+@@ -915,16 +916,18 @@ Decimal Decimal::round() const
+         return *this;
+ 
+     uint64_t result = m_data.coefficient();
+     const int numberOfDigits = countDigits(result);
+     const int numberOfDropDigits = -exponent();
+     if (numberOfDigits < numberOfDropDigits)
+         return zero(Positive);
+ 
++    // We're implementing round-half-away-from-zero, so we only need the one
++    // (the most significant) fractional digit:
+     result = scaleDown(result, numberOfDropDigits - 1);
+     if (result % 10 >= 5)
+         result += 10;
+     result /= 10;
+     return Decimal(sign(), 0, result);
+ }
+ 
+ double Decimal::toDouble() const