diff --git a/porting/liteos_m/kernel/BUILD.gn b/porting/liteos_m/kernel/BUILD.gn
index b0cead99a766a15403b49ff0520c1c81382dc8dd..664f9493766dfd946f73d9e9d96bb8b1890e23b0 100644
--- a/porting/liteos_m/kernel/BUILD.gn
+++ b/porting/liteos_m/kernel/BUILD.gn
@@ -174,6 +174,10 @@ static_library(libc) {
 
 static_library(libm) {
   sources = [
+    "src/math/__fpclassify.c",
+    "src/math/__fpclassifyl.c",
+    "src/math/__signbit.c",
+    "src/math/__signbitl.c",
     "src/math/exp_data.c",
     "src/math/frexp.c",
     "src/math/frexpl.c",
diff --git a/porting/liteos_m/kernel/src/math/__fpclassify.c b/porting/liteos_m/kernel/src/math/__fpclassify.c
new file mode 100644
index 0000000000000000000000000000000000000000..f7c0e2dfac828616b43f76664c6821de1b348f8d
--- /dev/null
+++ b/porting/liteos_m/kernel/src/math/__fpclassify.c
@@ -0,0 +1,11 @@
+#include <math.h>
+#include <stdint.h>
+
+int __fpclassify(double x)
+{
+	union {double f; uint64_t i;} u = {x};
+	int e = u.i>>52 & 0x7ff;
+	if (!e) return u.i<<1 ? FP_SUBNORMAL : FP_ZERO;
+	if (e==0x7ff) return u.i<<12 ? FP_NAN : FP_INFINITE;
+	return FP_NORMAL;
+}
diff --git a/porting/liteos_m/kernel/src/math/__fpclassifyl.c b/porting/liteos_m/kernel/src/math/__fpclassifyl.c
new file mode 100644
index 0000000000000000000000000000000000000000..e41781b689af7f7db420fc437cc4a72e4dd00c33
--- /dev/null
+++ b/porting/liteos_m/kernel/src/math/__fpclassifyl.c
@@ -0,0 +1,42 @@
+#include "libm.h"
+
+#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
+int __fpclassifyl(long double x)
+{
+	return __fpclassify(x);
+}
+#elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384
+int __fpclassifyl(long double x)
+{
+	union ldshape u = {x};
+	int e = u.i.se & 0x7fff;
+	int msb = u.i.m>>63;
+	if (!e && !msb)
+		return u.i.m ? FP_SUBNORMAL : FP_ZERO;
+	if (e == 0x7fff) {
+		/* The x86 variant of 80-bit extended precision only admits
+		 * one representation of each infinity, with the mantissa msb
+		 * necessarily set. The version with it clear is invalid/nan.
+		 * The m68k variant, however, allows either, and tooling uses
+		 * the version with it clear. */
+		if (__BYTE_ORDER == __LITTLE_ENDIAN && !msb)
+			return FP_NAN;
+		return u.i.m << 1 ? FP_NAN : FP_INFINITE;
+	}
+	if (!msb)
+		return FP_NAN;
+	return FP_NORMAL;
+}
+#elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384
+int __fpclassifyl(long double x)
+{
+	union ldshape u = {x};
+	int e = u.i.se & 0x7fff;
+	u.i.se = 0;
+	if (!e)
+		return u.i2.lo | u.i2.hi ? FP_SUBNORMAL : FP_ZERO;
+	if (e == 0x7fff)
+		return u.i2.lo | u.i2.hi ? FP_NAN : FP_INFINITE;
+	return FP_NORMAL;
+}
+#endif
diff --git a/porting/liteos_m/kernel/src/math/__signbit.c b/porting/liteos_m/kernel/src/math/__signbit.c
new file mode 100644
index 0000000000000000000000000000000000000000..e700b6b75fcb91e1919ad64b7da4e8c6a16f6065
--- /dev/null
+++ b/porting/liteos_m/kernel/src/math/__signbit.c
@@ -0,0 +1,13 @@
+#include "libm.h"
+
+// FIXME: macro in math.h
+int __signbit(double x)
+{
+	union {
+		double d;
+		uint64_t i;
+	} y = { x };
+	return y.i>>63;
+}
+
+
diff --git a/porting/liteos_m/kernel/src/math/__signbitl.c b/porting/liteos_m/kernel/src/math/__signbitl.c
new file mode 100644
index 0000000000000000000000000000000000000000..63b3dc5a08f3d89a3dd39a3ce74d7974317a0aa9
--- /dev/null
+++ b/porting/liteos_m/kernel/src/math/__signbitl.c
@@ -0,0 +1,14 @@
+#include "libm.h"
+
+#if (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
+int __signbitl(long double x)
+{
+	union ldshape u = {x};
+	return u.i.se >> 15;
+}
+#elif LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
+int __signbitl(long double x)
+{
+	return __signbit(x);
+}
+#endif