tests/tcg/mips: Add tests for R5900 three-operand MULTU1

Add a test for MULTU1.
Reviewed-by: NAleksandar Markovic <amarkovic@wavecomp.com>
Signed-off-by: NFredrik Noring <noring@nocrew.org>
Signed-off-by: NAleksandar Markovic <amarkovic@wavecomp.com>

tests/tcg/mips/mipsr5900/multu.c

 /*
- * Test R5900-specific three-operand MULTU.
+ * Test R5900-specific three-operand MULTU and MULTU1.
  */
 
 #include <stdio.h>
@@ -25,15 +25,44 @@ static uint64_t multu(uint32_t rs, uint32_t rt)
     return r;
 }
 
+static uint64_t multu1(uint32_t rs, uint32_t rt)
+{
+    uint32_t rd, lo, hi;
+    uint64_t r;
+
+    __asm__ __volatile__ (
+            "    multu1 %0, %3, %4\n"
+            "    mflo1 %1\n"
+            "    mfhi1 %2\n"
+            : "=r" (rd), "=r" (lo), "=r" (hi)
+            : "r" (rs), "r" (rt));
+    r = ((uint64_t)hi << 32) | (uint32_t)lo;
+
+    assert((uint64_t)rs * rt == r);
+    assert(rd == lo);
+
+    return r;
+}
+
+static uint64_t multu_variants(uint32_t rs, uint32_t rt)
+{
+    uint64_t rd  = multu(rs, rt);
+    uint64_t rd1 = multu1(rs, rt);
+
+    assert(rd == rd1);
+
+    return rd;
+}
+
 int main()
 {
-    assert(multu(17, 19) == 323);
-    assert(multu(77773, 99991) == 7776600043);
-    assert(multu(12207031, 305175781) == 3725290219116211);
+    assert(multu_variants(17, 19) == 323);
+    assert(multu_variants(77773, 99991) == 7776600043);
+    assert(multu_variants(12207031, 305175781) == 3725290219116211);
 
-    assert(multu(0x80000000U, 0x7FFFFFFF) == 0x3FFFFFFF80000000);
-    assert(multu(0x80000000U, 0x80000000U) ==  0x4000000000000000);
-    assert(multu(0xFFFFFFFFU, 0xFFFFFFFFU) ==  0xFFFFFFFE00000001U);
+    assert(multu_variants(0x80000000U, 0x7FFFFFFF) == 0x3FFFFFFF80000000);
+    assert(multu_variants(0x80000000U, 0x80000000U) ==  0x4000000000000000);
+    assert(multu_variants(0xFFFFFFFFU, 0xFFFFFFFFU) ==  0xFFFFFFFE00000001U);
 
     return 0;
 }