diff --git a/src/basic/math_trans/poly_atn.s b/src/basic/math_trans/e33e.poly_atn.s
similarity index 72%
rename from src/basic/math_trans/poly_atn.s
rename to src/basic/math_trans/e33e.poly_atn.s
index 11e2e898..c42a4d47 100644
--- a/src/basic/math_trans/poly_atn.s
+++ b/src/basic/math_trans/e33e.poly_atn.s
@@ -3,7 +3,12 @@
 ;; #LAYOUT# *  BASIC_0  #TAKE
 ;; #LAYOUT# *   *       #IGNORE
 
+; This file is under the MIT license, it contains code released by Microsoft Corporation.
+; See LICENSE for more information.
+
 ; Polynomial for the atn function
+;
+; This is verified to be identical to the original Microsoft implementation where it was named ATNCON
 
 
 !ifdef CONFIG_TRANSCENDENTAL_FUNCTIONS {
diff --git a/tools/similarity.c b/tools/similarity.c
index 69eb4f75..e304bede 100644
--- a/tools/similarity.c
+++ b/tools/similarity.c
@@ -32,7 +32,7 @@ unsigned short microsoft_basic_chunks[NUM_CHUNKS * 2] = {
     0xBDB3, 0xBDC1,
     0xBDDD, 0xBF51,
     0xBFB4, 0xBFEC,
-    0xE30E, 0xE33D,
+    0xE30E, 0xE37A,
 };