diff --git a/lib/libm/math.c b/lib/libm/math.c
index 6b65202cf0e58..6d82c93cfcebb 100644
--- a/lib/libm/math.c
+++ b/lib/libm/math.c
@@ -34,6 +34,7 @@ typedef union {
         uint64_t e : 8;
         uint64_t s : 1;
     };
+    uint32_t i;
 } float_s_t;
 
 #ifndef NDEBUG
@@ -58,6 +59,18 @@ float tanhf(float x) {
     return sinhf(x) / coshf(x);
 }
 
+float fabsf(float x) {
+    float_s_t u = {x};
+    u.i &= 0x7ffffffful; // remove sign bit
+    return u.f;
+}
+
+float nanf(const char *tagp) {
+    float_s_t u;
+    u.i = 0x7fc00000ul; // quiet NaN
+    return u.f;
+}
+
 /*****************************************************************************/
 /*****************************************************************************/
 // __fpclassifyf from musl-0.9.15