diff --git a/lib/msun/src/s_scalbn.c b/lib/msun/src/s_scalbn.c
index 3de663f8b670..2d4f7a3c6164 100644
--- a/lib/msun/src/s_scalbn.c
+++ b/lib/msun/src/s_scalbn.c
@@ -1,39 +1,47 @@
+/*
+ * Copyright (c) 2005-2020 Rich Felker, et al.
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ * Please see https://git.musl-libc.org/cgit/musl/tree/COPYRIGHT
+ * for all contributors to musl.
+ */
 #include <float.h>
 #include <math.h>
 #include <stdint.h>
 
 double scalbn(double x, int n)
 {
 	union {double f; uint64_t i;} u;
 	double_t y = x;
 
 	if (n > 1023) {
 		y *= 0x1p1023;
 		n -= 1023;
 		if (n > 1023) {
 			y *= 0x1p1023;
 			n -= 1023;
 			if (n > 1023)
 				n = 1023;
 		}
 	} else if (n < -1022) {
 		/* make sure final n < -53 to avoid double
 		   rounding in the subnormal range */
 		y *= 0x1p-1022 * 0x1p53;
 		n += 1022 - 53;
 		if (n < -1022) {
 			y *= 0x1p-1022 * 0x1p53;
 			n += 1022 - 53;
 			if (n < -1022)
 				n = -1022;
 		}
 	}
 	u.i = (uint64_t)(0x3ff+n)<<52;
 	x = y * u.f;
 	return x;
 }
 
 #if (LDBL_MANT_DIG == 53) && !defined(scalbn)
 __weak_reference(scalbn, ldexpl);
 __weak_reference(scalbn, scalbnl);
 #endif
diff --git a/lib/msun/src/s_scalbnf.c b/lib/msun/src/s_scalbnf.c
index 3a46470b5661..8cf1e01150da 100644
--- a/lib/msun/src/s_scalbnf.c
+++ b/lib/msun/src/s_scalbnf.c
@@ -1,33 +1,41 @@
+/*
+ * Copyright (c) 2005-2020 Rich Felker, et al.
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ * Please see https://git.musl-libc.org/cgit/musl/tree/COPYRIGHT
+ * for all contributors to musl.
+ */
 #include <math.h>
 #include <stdint.h>
 
 float scalbnf(float x, int n)
 {
 	union {float f; uint32_t i;} u;
 	float_t y = x;
 
 	if (n > 127) {
 		y *= 0x1p127f;
 		n -= 127;
 		if (n > 127) {
 			y *= 0x1p127f;
 			n -= 127;
 			if (n > 127)
 				n = 127;
 		}
 	} else if (n < -126) {
 		y *= 0x1p-126f * 0x1p24f;
 		n += 126 - 24;
 		if (n < -126) {
 			y *= 0x1p-126f * 0x1p24f;
 			n += 126 - 24;
 			if (n < -126)
 				n = -126;
 		}
 	}
 	u.i = (uint32_t)(0x7f+n)<<23;
 	x = y * u.f;
 	return x;
 }
 
 __strong_reference(scalbnf, ldexpf);
diff --git a/lib/msun/src/s_scalbnl.c b/lib/msun/src/s_scalbnl.c
index a79f79b33480..6044c1b1d4f7 100644
--- a/lib/msun/src/s_scalbnl.c
+++ b/lib/msun/src/s_scalbnl.c
@@ -1,41 +1,49 @@
+/*
+ * Copyright (c) 2005-2020 Rich Felker, et al.
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ * Please see https://git.musl-libc.org/cgit/musl/tree/COPYRIGHT
+ * for all contributors to musl.
+ */
 #include <math.h>
 #include <float.h>
 #include "math_private.h"
 #include "fpmath.h"
 /*
  * scalbnl (long double x, int n)
  * scalbnl(x,n) returns x* 2**n  computed by  exponent
  * manipulation rather than by actually performing an
  * exponentiation or a multiplication.
  */
 #if (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
 long double scalbnl(long double x, int n)
 {
 	union IEEEl2bits u;
 
 	if (n > 16383) {
 		x *= 0x1p16383L;
 		n -= 16383;
 		if (n > 16383) {
 			x *= 0x1p16383L;
 			n -= 16383;
 			if (n > 16383)
 				n = 16383;
 		}
 	} else if (n < -16382) {
 		x *= 0x1p-16382L * 0x1p113L;
 		n += 16382 - 113;
 		if (n < -16382) {
 			x *= 0x1p-16382L * 0x1p113L;
 			n += 16382 - 113;
 			if (n < -16382)
 				n = -16382;
 		}
 	}
 	u.e = 1.0;
 	u.xbits.expsign = 0x3fff + n;
 	return x * u.e;
 }
 __strong_reference(scalbnl, ldexpl);
 #endif