diff --git a/library/compiler-builtins/libm/src/math/acosf.rs b/library/compiler-builtins/libm/src/math/acosf.rs
index bbe29c17c131..ff07fe935016 100644
--- a/library/compiler-builtins/libm/src/math/acosf.rs
+++ b/library/compiler-builtins/libm/src/math/acosf.rs
@@ -1,3 +1,18 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/e_acosf.c */
+/*
+ * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
+ */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
 use super::sqrtf::sqrtf;
 
 const PIO2_HI: f32 = 1.5707962513e+00; /* 0x3fc90fda */
diff --git a/library/compiler-builtins/libm/src/math/asinf.rs b/library/compiler-builtins/libm/src/math/asinf.rs
index 597be4cb7f98..86944bb00576 100644
--- a/library/compiler-builtins/libm/src/math/asinf.rs
+++ b/library/compiler-builtins/libm/src/math/asinf.rs
@@ -1,3 +1,18 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/e_asinf.c */
+/*
+ * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
+ */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
 use super::fabsf::fabsf;
 use super::sqrt::sqrt;
 
diff --git a/library/compiler-builtins/libm/src/math/atanf.rs b/library/compiler-builtins/libm/src/math/atanf.rs
index 01c41f4ce178..b05152e2bc3e 100644
--- a/library/compiler-builtins/libm/src/math/atanf.rs
+++ b/library/compiler-builtins/libm/src/math/atanf.rs
@@ -1,3 +1,18 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/s_atanf.c */
+/*
+ * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
+ */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
 use super::fabsf;
 
 const ATAN_HI: [f32; 4] = [
diff --git a/library/compiler-builtins/libm/src/math/cosf.rs b/library/compiler-builtins/libm/src/math/cosf.rs
index 79df97e354a3..23faacdc26cf 100644
--- a/library/compiler-builtins/libm/src/math/cosf.rs
+++ b/library/compiler-builtins/libm/src/math/cosf.rs
@@ -1,3 +1,19 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/s_cosf.c */
+/*
+ * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
+ * Optimized by Bruce D. Evans.
+ */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
 use super::{k_cosf, k_sinf, rem_pio2f};
 
 use core::f64::consts::FRAC_PI_2;
diff --git a/library/compiler-builtins/libm/src/math/expm1.rs b/library/compiler-builtins/libm/src/math/expm1.rs
index 48082cd745cf..a00396524e8d 100644
--- a/library/compiler-builtins/libm/src/math/expm1.rs
+++ b/library/compiler-builtins/libm/src/math/expm1.rs
@@ -1,3 +1,15 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/s_expm1.c */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
 use core::f64;
 
 const O_THRESHOLD: f64 = 7.09782712893383973096e+02; /* 0x40862E42, 0xFEFA39EF */
diff --git a/library/compiler-builtins/libm/src/math/expm1f.rs b/library/compiler-builtins/libm/src/math/expm1f.rs
index 011e09b693d9..8f581733acd6 100644
--- a/library/compiler-builtins/libm/src/math/expm1f.rs
+++ b/library/compiler-builtins/libm/src/math/expm1f.rs
@@ -1,3 +1,18 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/s_expm1f.c */
+/*
+ * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
+ */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
 const O_THRESHOLD: f32 = 8.8721679688e+01; /* 0x42b17180 */
 const LN2_HI: f32 = 6.9313812256e-01; /* 0x3f317180 */
 const LN2_LO: f32 = 9.0580006145e-06; /* 0x3717f7d1 */
diff --git a/library/compiler-builtins/libm/src/math/k_cosf.rs b/library/compiler-builtins/libm/src/math/k_cosf.rs
index 83d13b2e998a..75579ef9bf49 100644
--- a/library/compiler-builtins/libm/src/math/k_cosf.rs
+++ b/library/compiler-builtins/libm/src/math/k_cosf.rs
@@ -1,3 +1,19 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/k_cosf.c */
+/*
+ * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
+ * Debugged and optimized by Bruce D. Evans.
+ */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
 /* |cos(x) - c(x)| < 2**-34.1 (~[-5.37e-11, 5.295e-11]). */
 const C0: f64 = -0.499999997251031003120; /* -0x1ffffffd0c5e81.0p-54 */
 const C1: f64 = 0.0416666233237390631894; /*  0x155553e1053a42.0p-57 */
diff --git a/library/compiler-builtins/libm/src/math/k_sinf.rs b/library/compiler-builtins/libm/src/math/k_sinf.rs
index bb2183afc7ca..bb519c9c09e9 100644
--- a/library/compiler-builtins/libm/src/math/k_sinf.rs
+++ b/library/compiler-builtins/libm/src/math/k_sinf.rs
@@ -1,3 +1,19 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/k_sinf.c */
+/*
+ * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
+ * Optimized by Bruce D. Evans.
+ */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
 /* |sin(x)/x - s(x)| < 2**-37.5 (~[-4.89e-12, 4.824e-12]). */
 const S1: f64 = -0.166666666416265235595; /* -0x15555554cbac77.0p-55 */
 const S2: f64 = 0.0083333293858894631756; /*  0x111110896efbb2.0p-59 */
diff --git a/library/compiler-builtins/libm/src/math/k_tanf.rs b/library/compiler-builtins/libm/src/math/k_tanf.rs
index db2e0caa7a5e..6d3da1dcc806 100644
--- a/library/compiler-builtins/libm/src/math/k_tanf.rs
+++ b/library/compiler-builtins/libm/src/math/k_tanf.rs
@@ -1,3 +1,14 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/k_tan.c */
+/*
+ * ====================================================
+ * Copyright 2004 Sun Microsystems, Inc.  All Rights Reserved.
+ *
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
 /* |tan(x)/x - t(x)| < 2**-25.5 (~[-2e-08, 2e-08]). */
 const T: [f64; 6] = [
     0.333331395030791399758,   /* 0x15554d3418c99f.0p-54 */
diff --git a/library/compiler-builtins/libm/src/math/rem_pio2_large.rs b/library/compiler-builtins/libm/src/math/rem_pio2_large.rs
index 52b47279cd91..462eb0345157 100644
--- a/library/compiler-builtins/libm/src/math/rem_pio2_large.rs
+++ b/library/compiler-builtins/libm/src/math/rem_pio2_large.rs
@@ -1,3 +1,15 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/k_rem_pio2.c */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunSoft, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
 use super::floor;
 use super::scalbn;
 
diff --git a/library/compiler-builtins/libm/src/math/rem_pio2f.rs b/library/compiler-builtins/libm/src/math/rem_pio2f.rs
index 73ec3775d3dc..e2368d93db64 100644
--- a/library/compiler-builtins/libm/src/math/rem_pio2f.rs
+++ b/library/compiler-builtins/libm/src/math/rem_pio2f.rs
@@ -1,3 +1,19 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/e_rem_pio2f.c */
+/*
+ * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
+ * Debugged and optimized by Bruce D. Evans.
+ */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
 use super::rem_pio2_large;
 
 use core::f64;
diff --git a/library/compiler-builtins/libm/src/math/sinf.rs b/library/compiler-builtins/libm/src/math/sinf.rs
index 09f62cddcae3..c9b02bcdc513 100644
--- a/library/compiler-builtins/libm/src/math/sinf.rs
+++ b/library/compiler-builtins/libm/src/math/sinf.rs
@@ -1,3 +1,19 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/s_sinf.c */
+/*
+ * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
+ * Optimized by Bruce D. Evans.
+ */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
 use super::{k_cosf, k_sinf, rem_pio2f};
 
 use core::f64::consts::FRAC_PI_2;
diff --git a/library/compiler-builtins/libm/src/math/tanf.rs b/library/compiler-builtins/libm/src/math/tanf.rs
index 6bfbe06c1b4b..15a462d4e19f 100644
--- a/library/compiler-builtins/libm/src/math/tanf.rs
+++ b/library/compiler-builtins/libm/src/math/tanf.rs
@@ -1,3 +1,19 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/s_tanf.c */
+/*
+ * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
+ * Optimized by Bruce D. Evans.
+ */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
 use super::{k_tanf, rem_pio2f};
 
 use core::f64::consts::FRAC_PI_2;