Implement byte swapping instructions on MIPS32 and MIPS64.

test/cctest/test-assembler-mips64.cc

Index: test/cctest/test-assembler-mips64.cc
diff --git a/test/cctest/test-assembler-mips64.cc b/test/cctest/test-assembler-mips64.cc
index 9529dab2422b69f094aa5e7ae2940d9a901ab963..f8f6b79f2209e057a44d942f077ebbf86f3d4991 100644
--- a/test/cctest/test-assembler-mips64.cc
+++ b/test/cctest/test-assembler-mips64.cc
@@ -3563,6 +3563,69 @@ TEST(BITSWAP) {
   }
 }
 
+TEST(SIGNEXTEND) {
+  if (kArchVariant == kMips64r6 || kArchVariant == kMips64r2) {
+    CcTest::InitializeVM();
+    Isolate* isolate = CcTest::i_isolate();
+    HandleScope scope(isolate);
+
+    typedef struct {
+      int64_t r1;
+      int64_t r2;
+      int64_t r3;
+      int64_t r4;
+    } T;
+    T t;
+
+    Assembler assm(isolate, NULL, 0);
+
+    __ ld(a4, MemOperand(a0, offsetof(T, r1)));
+    __ nop();
+    __ seh(a6, a4);
+    __ sll(a6, a6, 0);
+    __ sd(a6, MemOperand(a0, offsetof(T, r1)));
+
+    __ ld(a4, MemOperand(a0, offsetof(T, r2)));
+    __ nop();
+    __ seh(a6, a4);
+    __ sll(a6, a6, 0);
+    __ sd(a6, MemOperand(a0, offsetof(T, r2)));
+
+    __ ld(a4, MemOperand(a0, offsetof(T, r3)));
+    __ nop();
+    __ seb(a6, a4);
+    __ sll(a6, a6, 0);
+    __ sd(a6, MemOperand(a0, offsetof(T, r3)));
+
+    __ ld(a4, MemOperand(a0, offsetof(T, r4)));
+    __ nop();
+    __ seb(a6, a4);
+    __ sll(a6, a6, 0);
+    __ sd(a6, MemOperand(a0, offsetof(T, r4)));
+
+    __ jr(ra);
+    __ nop();
+
+    CodeDesc desc;
+
+    assm.GetCode(&desc);
+    Handle<Code> code = isolate->factory()->NewCode(
+        desc, Code::ComputeFlags(Code::STUB), Handle<Code>());
+
+    F3 f = FUNCTION_CAST<F3>(code->entry());
+    t.r1 = 0x15C3;
+    t.r2 = 0xFCDE;
+    t.r3 = 0xC3;
+    t.r4 = 0x5E;
+    Object* dummy = CALL_GENERATED_CODE(isolate, f, &t, 0, 0, 0, 0);
+    USE(dummy);
+
+    CHECK_EQ(static_cast<int64_t>(0x00000000000015C3), t.r1);
+    CHECK_EQ(static_cast<int64_t>(0xFFFFFFFFFFFFFCDE), t.r2);
+    CHECK_EQ(static_cast<int64_t>(0xFFFFFFFFFFFFFFC3), t.r3);
+    CHECK_EQ(static_cast<int64_t>(0x000000000000005E), t.r4);
+  }
+}
 
 TEST(class_fmt) {
   if (kArchVariant == kMips64r6) {