diff --git a/rostests/apitests/msvcrt/CMakeLists.txt b/rostests/apitests/msvcrt/CMakeLists.txt
index fc9797127d9..59c6772b378 100644
--- a/rostests/apitests/msvcrt/CMakeLists.txt
+++ b/rostests/apitests/msvcrt/CMakeLists.txt
@@ -2,6 +2,7 @@
 add_definitions(-D_DLL -D__USE_CRTIMP)
 
 list(APPEND SOURCE
+    ieee.c
     splitpath.c
     testlist.c)
 
diff --git a/rostests/apitests/msvcrt/ieee.c b/rostests/apitests/msvcrt/ieee.c
new file mode 100644
index 00000000000..528e9c3ad61
--- /dev/null
+++ b/rostests/apitests/msvcrt/ieee.c
@@ -0,0 +1,197 @@
+/*
+ * PROJECT:         ReactOS api tests
+ * LICENSE:         GPL - See COPYING in the top level directory
+ * PURPOSE:         Tests for IEEE floatting-point functions
+ * PROGRAMMER:      Pierre Schweitzer (pierre@reactos.org)
+ */
+
+#include <wine/test.h>
+#include <float.h>
+
+typedef union
+{
+    double d;
+    long long l;
+} ieee_double;
+
+void test_finite(void)
+{
+    ieee_double tested;
+
+    tested.l = 0xFFFFFFFFFFFFFFFFLL;
+    ok(_finite(tested.d) == FALSE, "_finite = TRUE\n");
+    tested.l = 0xFFF8000000000001LL;
+    ok(_finite(tested.d) == FALSE, "_finite = TRUE\n");
+    tested.l = 0xFFF7FFFFFFFFFFFFLL;
+    ok(_finite(tested.d) == FALSE, "_finite = TRUE\n");
+    tested.l = 0xFFF0000000000001LL;
+    ok(_finite(tested.d) == FALSE, "_finite = TRUE\n");
+    tested.l = 0xFFF0000000000000LL;
+    ok(_finite(tested.d) == FALSE, "_finite = TRUE\n");
+    tested.l = 0xFFEFFFFFFFFFFFFFLL;
+    ok(_finite(tested.d) == TRUE, "_finite = FALSE\n");
+    tested.l = 0x8010000000000000LL;
+    ok(_finite(tested.d) == TRUE, "_finite = FALSE\n");
+    tested.l = 0x800FFFFFFFFFFFFFLL;
+    ok(_finite(tested.d) == TRUE, "_finite = FALSE\n");
+    tested.l = 0x8000000000000001LL;
+    ok(_finite(tested.d) == TRUE, "_finite = FALSE\n");
+    tested.l = 0x8000000000000000LL;
+    ok(_finite(tested.d) == TRUE, "_finite = FALSE\n");
+    tested.l = 0x0000000000000000LL;
+    ok(_finite(tested.d) == TRUE, "_finite = FALSE\n");
+    tested.l = 0x0000000000000001LL;
+    ok(_finite(tested.d) == TRUE, "_finite = FALSE\n");
+    tested.l = 0x000FFFFFFFFFFFFFLL;
+    ok(_finite(tested.d) == TRUE, "_finite = FALSE\n");
+    tested.l = 0x0010000000000000LL;
+    ok(_finite(tested.d) == TRUE, "_finite = FALSE\n");
+    tested.l = 0x7FEFFFFFFFFFFFFFLL;
+    ok(_finite(tested.d) == TRUE, "_finite = FALSE\n");
+    tested.l = 0x7FF0000000000000LL;
+    ok(_finite(tested.d) == FALSE, "_finite = TRUE\n");
+    tested.l = 0x7FF0000000000001LL;
+    ok(_finite(tested.d) == FALSE, "_finite = TRUE\n");
+    tested.l = 0x7FF7FFFFFFFFFFFFLL;
+    ok(_finite(tested.d) == FALSE, "_finite = TRUE\n");
+    tested.l = 0x7FF8000000000000LL;
+    ok(_finite(tested.d) == FALSE, "_finite = TRUE\n");
+    tested.l = 0x7FFFFFFFFFFFFFFFLL;
+    ok(_finite(tested.d) == FALSE, "_finite = TRUE\n");
+}
+
+void test_fpclass(void)
+{
+    int class;
+    ieee_double tested;
+
+    tested.l = 0xFFFFFFFFFFFFFFFFLL;
+    class = _fpclass(tested.d);
+    ok(class == _FPCLASS_QNAN, "class = %d\n", class);
+    tested.l = 0xFFF8000000000001LL;
+    class = _fpclass(tested.d);
+    ok(class == _FPCLASS_QNAN, "class = %d\n", class);
+    tested.l = 0xFFF7FFFFFFFFFFFFLL;
+    class = _fpclass(tested.d);
+    /* According to IEEE, it should be Signaling NaN, but
+     * on w2k3, it's Quiet NAN
+     * ok(class == _FPCLASS_SNAN, "class = %d\n", class);
+     */
+    ok(class == _FPCLASS_QNAN, "class = %d\n", class);
+    tested.l = 0xFFF0000000000001LL;
+    class = _fpclass(tested.d);
+    /* According to IEEE, it should be Signaling NaN, but
+     * on w2k3, it's Quiet NAN
+     * ok(class == _FPCLASS_SNAN, "class = %d\n", class);
+     */
+    ok(class == _FPCLASS_QNAN, "class = %d\n", class);
+    tested.l = 0xFFF0000000000000LL;
+    class = _fpclass(tested.d);
+    ok(class == _FPCLASS_NINF, "class = %d\n", class);
+    tested.l = 0xFFEFFFFFFFFFFFFFLL;
+    class = _fpclass(tested.d);
+    ok(class == _FPCLASS_NN, "class = %d\n", class);
+    tested.l = 0x8010000000000000LL;
+    class = _fpclass(tested.d);
+    ok(class == _FPCLASS_NN, "class = %d\n", class);
+    tested.l = 0x800FFFFFFFFFFFFFLL;
+    class = _fpclass(tested.d);
+    ok(class == _FPCLASS_ND, "class = %d\n", class);
+    tested.l = 0x8000000000000001LL;
+    class = _fpclass(tested.d);
+    ok(class == _FPCLASS_ND, "class = %d\n", class);
+    tested.l = 0x8000000000000000LL;
+    class = _fpclass(tested.d);
+    ok(class == _FPCLASS_NZ, "class = %d\n", class);
+    tested.l = 0x0000000000000000LL;
+    class = _fpclass(tested.d);
+    ok(class == _FPCLASS_PZ, "class = %d\n", class);
+    tested.l = 0x0000000000000001LL;
+    class = _fpclass(tested.d);
+    ok(class == _FPCLASS_PD, "class = %d\n", class);
+    tested.l = 0x000FFFFFFFFFFFFFLL;
+    class = _fpclass(tested.d);
+    ok(class == _FPCLASS_PD, "class = %d\n", class);
+    tested.l = 0x0010000000000000LL;
+    class = _fpclass(tested.d);
+    ok(class == _FPCLASS_PN, "class = %d\n", class);
+    tested.l = 0x7FEFFFFFFFFFFFFFLL;
+    class = _fpclass(tested.d);
+    ok(class == _FPCLASS_PN, "class = %d\n", class);
+    tested.l = 0x7FF0000000000000LL;
+    class = _fpclass(tested.d);
+    ok(class == _FPCLASS_PINF, "class = %d\n", class);
+    tested.l = 0x7FF0000000000001LL;
+    class = _fpclass(tested.d);
+    /* According to IEEE, it should be Signaling NaN, but
+     * on w2k3, it's Quiet NAN
+     * ok(class == _FPCLASS_SNAN, "class = %d\n", class);
+     */
+    ok(class == _FPCLASS_QNAN, "class = %d\n", class);
+    tested.l = 0x7FF7FFFFFFFFFFFFLL;
+    class = _fpclass(tested.d);
+    /* According to IEEE, it should be Signaling NaN, but
+     * on w2k3, it's Quiet NAN
+     * ok(class == _FPCLASS_SNAN, "class = %d\n", class);
+     */
+    ok(class == _FPCLASS_QNAN, "class = %d\n", class);
+    tested.l = 0x7FF8000000000000LL;
+    class = _fpclass(tested.d);
+    ok(class == _FPCLASS_QNAN, "class = %d\n", class);
+    tested.l = 0x7FFFFFFFFFFFFFFFLL;
+    class = _fpclass(tested.d);
+    ok(class == _FPCLASS_QNAN, "class = %d\n", class);
+}
+
+void test_isnan(void)
+{
+    ieee_double tested;
+
+    tested.l = 0xFFFFFFFFFFFFFFFFLL;
+    ok(_isnan(tested.d) == TRUE, "_isnan = FALSE\n");
+    tested.l = 0xFFF8000000000001LL;
+    ok(_isnan(tested.d) == TRUE, "_isnan = FALSE\n");
+    tested.l = 0xFFF7FFFFFFFFFFFFLL;
+    ok(_isnan(tested.d) == TRUE, "_isnan = FALSE\n");
+    tested.l = 0xFFF0000000000001LL;
+    ok(_isnan(tested.d) == TRUE, "_isnan = FALSE\n");
+    tested.l = 0xFFF0000000000000LL;
+    ok(_isnan(tested.d) == FALSE, "_isnan = TRUE\n");
+    tested.l = 0xFFEFFFFFFFFFFFFFLL;
+    ok(_isnan(tested.d) == FALSE, "_isnan = TRUE\n");
+    tested.l = 0x8010000000000000LL;
+    ok(_isnan(tested.d) == FALSE, "_isnan = TRUE\n");
+    tested.l = 0x800FFFFFFFFFFFFFLL;
+    ok(_isnan(tested.d) == FALSE, "_isnan = TRUE\n");
+    tested.l = 0x8000000000000001LL;
+    ok(_isnan(tested.d) == FALSE, "_isnan = TRUE\n");
+    tested.l = 0x8000000000000000LL;
+    ok(_isnan(tested.d) == FALSE, "_isnan = TRUE\n");
+    tested.l = 0x0000000000000000LL;
+    ok(_isnan(tested.d) == FALSE, "_isnan = TRUE\n");
+    tested.l = 0x0000000000000001LL;
+    ok(_isnan(tested.d) == FALSE, "_isnan = TRUE\n");
+    tested.l = 0x000FFFFFFFFFFFFFLL;
+    ok(_isnan(tested.d) == FALSE, "_isnan = TRUE\n");
+    tested.l = 0x0010000000000000LL;
+    ok(_isnan(tested.d) == FALSE, "_isnan = TRUE\n");
+    tested.l = 0x7FEFFFFFFFFFFFFFLL;
+    ok(_isnan(tested.d) == FALSE, "_isnan = TRUE\n");
+    tested.l = 0x7FF0000000000000LL;
+    ok(_isnan(tested.d) == FALSE, "_isnan = TRUE\n");
+    tested.l = 0x7FF0000000000001LL;
+    ok(_isnan(tested.d) == TRUE, "_isnan = FALSE\n");
+    tested.l = 0x7FF7FFFFFFFFFFFFLL;
+    ok(_isnan(tested.d) == TRUE, "_isnan = FALSE\n");
+    tested.l = 0x7FF8000000000000LL;
+    ok(_isnan(tested.d) == TRUE, "_isnan = FALSE\n");
+    tested.l = 0x7FFFFFFFFFFFFFFFLL;
+    ok(_isnan(tested.d) == TRUE, "_isnan = FALSE\n");
+}
+
+START_TEST(ieee)
+{
+    test_finite();
+    test_fpclass();
+    test_isnan();
+}
diff --git a/rostests/apitests/msvcrt/msvcrt_apitest.rbuild b/rostests/apitests/msvcrt/msvcrt_apitest.rbuild
index ce758772758..b21f5fdc36c 100644
--- a/rostests/apitests/msvcrt/msvcrt_apitest.rbuild
+++ b/rostests/apitests/msvcrt/msvcrt_apitest.rbuild
@@ -7,6 +7,7 @@
 	<library>pseh</library>
 	<file>testlist.c</file>
 
+	<file>ieee.c</file>
 	<file>splitpath.c</file>
 
 </module>
diff --git a/rostests/apitests/msvcrt/testlist.c b/rostests/apitests/msvcrt/testlist.c
index d54fb7efc9f..0e57890b48f 100644
--- a/rostests/apitests/msvcrt/testlist.c
+++ b/rostests/apitests/msvcrt/testlist.c
@@ -5,10 +5,12 @@
 #define STANDALONE
 #include "wine/test.h"
 
+extern void func_ieee(void);
 extern void func_splitpath(void);
 
 const struct test winetest_testlist[] =
 {
+    { "ieee", func_ieee },
     { "splitpath", func_splitpath },
 
     { 0, 0 }