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

Add a test for MULTU.
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/Makefile

@@ -9,6 +9,7 @@ CC      = $(CROSS)gcc
 CFLAGS  = -Wall -mabi=32 -march=r5900 -static
 
 TESTCASES = mult.tst
+TESTCASES += multu.tst
 
 all: $(TESTCASES)
 

tests/tcg/mips/mipsr5900/multu.c

+/*
+ * Test R5900-specific three-operand MULTU.
+ */
+
+#include <stdio.h>
+#include <inttypes.h>
+#include <assert.h>
+
+static uint64_t multu(uint32_t rs, uint32_t rt)
+{
+    uint32_t rd, lo, hi;
+    uint64_t r;
+
+    __asm__ __volatile__ (
+            "    multu %0, %3, %4\n"
+            "    mflo %1\n"
+            "    mfhi %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;
+}
+
+int main()
+{
+    assert(multu(17, 19) == 323);
+    assert(multu(77773, 99991) == 7776600043);
+    assert(multu(12207031, 305175781) == 3725290219116211);
+
+    assert(multu(0x80000000U, 0x7FFFFFFF) == 0x3FFFFFFF80000000);
+    assert(multu(0x80000000U, 0x80000000U) ==  0x4000000000000000);
+    assert(multu(0xFFFFFFFFU, 0xFFFFFFFFU) ==  0xFFFFFFFE00000001U);
+
+    return 0;
+}