1 files changed, 39 insertions, 20 deletions

diff --git a/deps/icu-small/source/i18n/double-conversion-diy-fp.h b/deps/icu-small/source/i18n/double-conversion-diy-fp.h
index 21896851d2..5820abedf3 100644
--- a/deps/icu-small/source/i18n/double-conversion-diy-fp.h
+++ b/deps/icu-small/source/i18n/double-conversion-diy-fp.h
@@ -50,36 +50,55 @@ namespace double_conversion {
 // with a uint64 significand and an int exponent. Normalized DiyFp numbers will
 // have the most significant bit of the significand set.
 // Multiplication and Subtraction do not normalize their results.
-// DiyFp are not designed to contain special doubles (NaN and Infinity).
+// DiyFp store only non-negative numbers and are not designed to contain special
+// doubles (NaN and Infinity).
 class DiyFp {
  public:
   static const int kSignificandSize = 64;
 
   DiyFp() : f_(0), e_(0) {}
-  DiyFp(uint64_t significand, int exponent) : f_(significand), e_(exponent) {}
+  DiyFp(const uint64_t significand, const int32_t exponent) : f_(significand), e_(exponent) {}
 
-  // this = this - other.
+  // this -= other.
   // The exponents of both numbers must be the same and the significand of this
-  // must be bigger than the significand of other.
+  // must be greater or equal than the significand of other.
   // The result will not be normalized.
   void Subtract(const DiyFp& other) {
-    ASSERT(e_ == other.e_);
-    ASSERT(f_ >= other.f_);
+    DOUBLE_CONVERSION_ASSERT(e_ == other.e_);
+    DOUBLE_CONVERSION_ASSERT(f_ >= other.f_);
     f_ -= other.f_;
   }
 
   // Returns a - b.
-  // The exponents of both numbers must be the same and this must be bigger
-  // than other. The result will not be normalized.
+  // The exponents of both numbers must be the same and a must be greater
+  // or equal than b. The result will not be normalized.
   static DiyFp Minus(const DiyFp& a, const DiyFp& b) {
     DiyFp result = a;
     result.Subtract(b);
     return result;
   }
 
-
-  // this = this * other.
-  void Multiply(const DiyFp& other);
+  // this *= other.
+  void Multiply(const DiyFp& other) {
+    // Simply "emulates" a 128 bit multiplication.
+    // However: the resulting number only contains 64 bits. The least
+    // significant 64 bits are only used for rounding the most significant 64
+    // bits.
+    const uint64_t kM32 = 0xFFFFFFFFU;
+    const uint64_t a = f_ >> 32;
+    const uint64_t b = f_ & kM32;
+    const uint64_t c = other.f_ >> 32;
+    const uint64_t d = other.f_ & kM32;
+    const uint64_t ac = a * c;
+    const uint64_t bc = b * c;
+    const uint64_t ad = a * d;
+    const uint64_t bd = b * d;
+    // By adding 1U << 31 to tmp we round the final result.
+    // Halfway cases will be rounded up.
+    const uint64_t tmp = (bd >> 32) + (ad & kM32) + (bc & kM32) + (1U << 31);
+    e_ += other.e_ + 64;
+    f_ = ac + (ad >> 32) + (bc >> 32) + (tmp >> 32);
+  }
 
   // returns a * b;
   static DiyFp Times(const DiyFp& a, const DiyFp& b) {
@@ -89,13 +108,13 @@ class DiyFp {
   }
 
   void Normalize() {
-    ASSERT(f_ != 0);
+    DOUBLE_CONVERSION_ASSERT(f_ != 0);
     uint64_t significand = f_;
-    int exponent = e_;
+    int32_t exponent = e_;
 
-    // This method is mainly called for normalizing boundaries. In general
-    // boundaries need to be shifted by 10 bits. We thus optimize for this case.
-    const uint64_t k10MSBits = UINT64_2PART_C(0xFFC00000, 00000000);
+    // This method is mainly called for normalizing boundaries. In general,
+    // boundaries need to be shifted by 10 bits, and we optimize for this case.
+    const uint64_t k10MSBits = DOUBLE_CONVERSION_UINT64_2PART_C(0xFFC00000, 00000000);
     while ((significand & k10MSBits) == 0) {
       significand <<= 10;
       exponent -= 10;
@@ -115,16 +134,16 @@ class DiyFp {
   }
 
   uint64_t f() const { return f_; }
-  int e() const { return e_; }
+  int32_t e() const { return e_; }
 
   void set_f(uint64_t new_value) { f_ = new_value; }
-  void set_e(int new_value) { e_ = new_value; }
+  void set_e(int32_t new_value) { e_ = new_value; }
 
  private:
-  static const uint64_t kUint64MSB = UINT64_2PART_C(0x80000000, 00000000);
+  static const uint64_t kUint64MSB = DOUBLE_CONVERSION_UINT64_2PART_C(0x80000000, 00000000);
 
   uint64_t f_;
-  int e_;
+  int32_t e_;
 };
 
 }  // namespace double_conversion