Truncate rather than round to nearest when performing float-to-integer...

test/cctest/test-api.cc

 // Copyright 2007-2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 10569 matching lines @@
     result = CompileRun("for (var i = 0; i < 8; i++) {"
                         "  ext_array[i] = 5;"
                         "}"
                         "for (var i = 0; i < 8; i++) {"
                         "  ext_array[i] = -Infinity;"
                         "}"
                         "ext_array[5];");
     CHECK_EQ(0, result->Int32Value());
     CHECK_EQ(0,
              i::Smi::cast(jsobj->GetElement(5)->ToObjectChecked())->value());
+
+    // Check truncation behavior of integral arrays.
+    const char* unsigned_data =
+        "var source_data = [0.6, 10.6];"
+        "var expected_results = [0, 10];";
+    const char* signed_data =
+        "var source_data = [0.6, 10.6, -0.6, -10.6];"
+        "var expected_results = [0, 10, 0, -10];";
+    bool is_unsigned =
+        (array_type == v8::kExternalUnsignedByteArray ||
+         array_type == v8::kExternalUnsignedShortArray ||
+         array_type == v8::kExternalUnsignedIntArray);
+
+    i::OS::SNPrintF(test_buf,
+                    "%s"
+                    "var all_passed = true;"
+                    "for (var i = 0; i < source_data.length; i++) {"
+                    "  for (var j = 0; j < 8; j++) {"
+                    "    ext_array[j] = source_data[i];"
+                    "  }"
+                    "  all_passed = all_passed &&"
+                    "               (ext_array[5] == expected_results[i]);"
+                    "}"
+                    "all_passed;",
+                    (is_unsigned ? unsigned_data : signed_data));
+    result = CompileRun(test_buf.start());
+    CHECK_EQ(true, result->BooleanValue());
   }
 
   result = CompileRun("ext_array[3] = 33;"
                       "delete ext_array[3];"
                       "ext_array[3];");
   CHECK_EQ(33, result->Int32Value());
 
   result = CompileRun("ext_array[0] = 10; ext_array[1] = 11;"
                       "ext_array[2] = 12; ext_array[3] = 13;"
                       "ext_array.__defineGetter__('2',"
@@ skipping 1570 matching lines @@
   v8::Context::Scope context_scope(context.local());
 
   v8::Handle<v8::ObjectTemplate> tmpl = v8::ObjectTemplate::New();
   tmpl->SetNamedPropertyHandler(Getter, NULL, NULL, NULL, Enumerator);
   context->Global()->Set(v8_str("o"), tmpl->NewInstance());
   v8::Handle<v8::Array> result = v8::Handle<v8::Array>::Cast(CompileRun(
         "var result = []; for (var k in o) result.push(k); result"));
   CHECK_EQ(1, result->Length());
   CHECK_EQ(v8_str("universalAnswer"), result->Get(0));
 }