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

Add a test for MULT.
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

+-include ../../config-host.mak
+
+CROSS=mipsr5900el-unknown-linux-gnu-
+
+SIM=qemu-mipsel
+SIM_FLAGS=-cpu R5900
+
+CC      = $(CROSS)gcc
+CFLAGS  = -Wall -mabi=32 -march=r5900 -static
+
+TESTCASES = mult.tst
+
+all: $(TESTCASES)
+
+%.tst: %.c
+	$(CC) $(CFLAGS) $< -o $@
+
+check: $(TESTCASES)
+	@for case in $(TESTCASES); do \
+        echo $(SIM) $(SIM_FLAGS) ./$$case;\
+        $(SIM) $(SIM_FLAGS) ./$$case; \
+	done
+
+clean:
+	$(RM) -rf $(TESTCASES)

tests/tcg/mips/mipsr5900/mult.c

+/*
+ * Test R5900-specific three-operand MULT.
+ */
+
+#include <stdio.h>
+#include <inttypes.h>
+#include <assert.h>
+
+static int64_t mult(int32_t rs, int32_t rt)
+{
+    int32_t rd, lo, hi;
+    int64_t r;
+
+    __asm__ __volatile__ (
+            "    mult %0, %3, %4\n"
+            "    mflo %1\n"
+            "    mfhi %2\n"
+            : "=r" (rd), "=r" (lo), "=r" (hi)
+            : "r" (rs), "r" (rt));
+    r = ((int64_t)hi << 32) | (uint32_t)lo;
+
+    assert((int64_t)rs * rt == r);
+    assert(rd == lo);
+
+    return r;
+}
+
+static void verify_mult_negations(int32_t rs, int32_t rt, int64_t expected)
+{
+    assert(mult(rs, rt) == expected);
+    assert(mult(-rs, rt) == -expected);
+    assert(mult(rs, -rt) == -expected);
+    assert(mult(-rs, -rt) == expected);
+}
+
+int main()
+{
+    verify_mult_negations(17, 19, 323);
+    verify_mult_negations(77773, 99991, 7776600043);
+    verify_mult_negations(12207031, 305175781, 3725290219116211);
+
+    assert(mult(-0x80000000,  0x7FFFFFFF) == -0x3FFFFFFF80000000);
+    assert(mult(-0x80000000, -0x7FFFFFFF) ==  0x3FFFFFFF80000000);
+    assert(mult(-0x80000000, -0x80000000) ==  0x4000000000000000);
+
+    return 0;
+}