MIPS: Fix rounding in Uint8ClampedArray setter.

src/mips/simulator-mips.cc

Index: src/mips/simulator-mips.cc
diff --git a/src/mips/simulator-mips.cc b/src/mips/simulator-mips.cc
index 66d0da71fa4260e086b77b99f8f3773466db5d44..cf87f93602e51d55d27873e6843b7e63c5a1d6cb 100644
--- a/src/mips/simulator-mips.cc
+++ b/src/mips/simulator-mips.cc
@@ -2068,10 +2068,15 @@ void Simulator::DecodeTypeRegister(Instruction* instr) {
               // 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);