diff --git a/lib/msun/src/s_roundf.c b/lib/msun/src/s_roundf.c
--- a/lib/msun/src/s_roundf.c
+++ b/lib/msun/src/s_roundf.c
@@ -32,22 +32,42 @@
 float
 roundf(float x)
 {
-	float t;
-	uint32_t hx;
+	uint32_t hx, ix, sign;
+	int e;
 
 	GET_FLOAT_WORD(hx, x);
-	if ((hx & 0x7fffffff) == 0x7f800000)
-		return (x + x);
-
-	if (!(hx & 0x80000000)) {
-		t = floorf(x);
-		if (t - x <= -0.5F)
-			t += 1;
-		return (t);
-	} else {
-		t = floorf(-x);
-		if (t + x <= -0.5F)
-			t += 1;
-		return (-t);
+	sign = hx & 0x80000000;
+	ix = hx & 0x7fffffff;
+
+	/* Inf/NaN or |x| >= 2^23 */
+	if (ix >= 0x4b000000)
+		return (ix > 0x7f800000) ? (x + x) : x;
+
+	e = (ix >> 23) - 127;
+
+	/* |x| < 0.5: return ±0 */
+	if (e < -1) {
+		SET_FLOAT_WORD(x, sign);
+		return x;
+	}
+
+	/* |x| in [0.5, 1): return ±1 */
+	if (e < 0) {
+		SET_FLOAT_WORD(x, sign | 0x3f800000);
+		return x;
 	}
+
+	/* 1 <= |x| < 2^23: truncate and add 0.5 based on fraction */
+	uint32_t mask = 0x007fffff >> e;
+
+	/* If no fractional bits, already integer */
+	if ((ix & mask) == 0)
+		return x;
+
+	/* Add 0.5 in the correct bit position */
+	hx += 0x00400000 >> e;
+	hx &= ~mask;
+
+	SET_FLOAT_WORD(x, hx);
+	return x;
 }