Support Bigint parameters in Int32x4 constructor

runtime/vm/bigint_operations.cc

 // Copyright 2012 Google Inc. All Rights Reserved.
 
 #include "vm/bigint_operations.h"
 
 #include "platform/assert.h"
 #include "platform/utils.h"
 
 #include "vm/double_internals.h"
 #include "vm/exceptions.h"
 #include "vm/object_store.h"
@@ skipping 675 matching lines @@
   }
   ASSERT(FitsIntoInt64(bigint));
   int64_t value = AbsToUint64(bigint);
   if (bigint.IsNegative()) {
     value = -value;
   }
   return value;
 }
 
 
+uint32_t BigintOperations::TruncateToUint32(const Bigint& bigint) {
+  uint32_t value = 0;
+  for (intptr_t i = bigint.Length() - 1; i >= 0; i--) {
+    value <<= kDigitBitSize;
+    value += static_cast<uint32_t>(bigint.GetChunkAt(i));
+  }
+  return value;
+}
+
+
 bool BigintOperations::AbsFitsIntoUint64(const Bigint& bigint) {
   intptr_t b_length = bigint.Length();
   intptr_t num_bits = CountBits(bigint.GetChunkAt(b_length - 1));
   num_bits += (kDigitBitSize * (b_length - 1));
   if (num_bits > 64) return false;
   return true;
 }
 
 
 bool BigintOperations::FitsIntoUint64(const Bigint& bigint) {
@@ skipping 1092 matching lines @@
 intptr_t BigintOperations::CountBits(Chunk digit) {
   intptr_t result = 0;
   while (digit != 0) {
     digit >>= 1;
     result++;
   }
   return result;
 }
 
 }  // namespace dart