MIPS: Fix rounding in Uint8ClampedArray setter.

src/mips/simulator-mips.cc

 // Copyright 2011 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 2050 matching lines @@
             case C_OLE_D:
               set_fcsr_bit(fcsr_cc, (fs <= ft));
               break;
             case C_ULE_D:
               set_fcsr_bit(fcsr_cc, (fs <= ft) || (isnan(fs) || isnan(ft)));
               break;
             case CVT_W_D:   // Convert double to word.
               // Rounding modes are not yet supported.
               ASSERT((FCSR_ & 3) == 0);
               // In rounding mode 0 it should behave like ROUND.
-            case ROUND_W_D:  // Round double to word.
+            case ROUND_W_D:  // Round double to word (round half to even).
               {
-                double rounded = fs > 0 ? floor(fs + 0.5) : ceil(fs - 0.5);
+                double rounded = floor(fs + 0.5);
                 int32_t result = static_cast<int32_t>(rounded);
+                if ((result & 1) != 0 && result - fs == 0.5) {
+                  // If the number is halfway between two integers,
+                  // round to the even one.
+                  result--;
+                }
                 set_fpu_register(fd_reg, result);
                 if (set_fcsr_round_error(fs, rounded)) {
                   set_fpu_register(fd_reg, kFPUInvalidResult);
                 }
               }
               break;
             case TRUNC_W_D:  // Truncate double to word (round towards 0).
               {
                 double rounded = trunc(fs);
                 int32_t result = static_cast<int32_t>(rounded);
@@ skipping 747 matching lines @@
 }
 
 
 #undef UNSUPPORTED
 
 } }  // namespace v8::internal
 
 #endif  // USE_SIMULATOR
 
 #endif  // V8_TARGET_ARCH_MIPS