diff --git a/src/e_j0.c b/src/e_j0.c
index f03c054..684bd56 100644
--- a/src/e_j0.c
+++ b/src/e_j0.c
@@ -11,6 +11,8 @@
  * ====================================================
  */
 
+#include <assert.h>
+
 #include "cdefs-compat.h"
 //__FBSDID("$FreeBSD: src/lib/msun/src/e_j0.c,v 1.9 2008/02/22 02:30:35 das Exp $");
 
@@ -276,6 +278,7 @@ static const double pS2[5] = {
 	int32_t ix;
 	GET_HIGH_WORD(ix,x);
 	ix &= 0x7fffffff;
+        assert(ix>=0x40000000 && ix<=0x48000000);
 	if(ix>=0x40200000)     {p = pR8; q= pS8;}
 	else if(ix>=0x40122E8B){p = pR5; q= pS5;}
 	else if(ix>=0x4006DB6D){p = pR3; q= pS3;}
@@ -372,6 +375,7 @@ static const double qS2[6] = {
 	int32_t ix;
 	GET_HIGH_WORD(ix,x);
 	ix &= 0x7fffffff;
+        assert(ix>=0x40000000 && ix<=0x48000000);
 	if(ix>=0x40200000)     {p = qR8; q= qS8;}
 	else if(ix>=0x40122E8B){p = qR5; q= qS5;}
 	else if(ix>=0x4006DB6D){p = qR3; q= qS3;}
diff --git a/src/e_j0f.c b/src/e_j0f.c
index a621e56..ee32fe1 100644
--- a/src/e_j0f.c
+++ b/src/e_j0f.c
@@ -13,6 +13,8 @@
  * ====================================================
  */
 
+#include <assert.h>
+
 #include "cdefs-compat.h"
 //__FBSDID("$FreeBSD: src/lib/msun/src/e_j0f.c,v 1.8 2008/02/22 02:30:35 das Exp $");
 
@@ -232,6 +234,7 @@ static const float pS2[5] = {
 	int32_t ix;
 	GET_FLOAT_WORD(ix,x);
 	ix &= 0x7fffffff;
+        assert(ix>=0x40000000 && ix<=0x48000000);
 	if(ix>=0x41000000)     {p = pR8; q= pS8;}
 	else if(ix>=0x40f71c58){p = pR5; q= pS5;}
 	else if(ix>=0x4036db68){p = pR3; q= pS3;}
@@ -328,6 +331,7 @@ static const float qS2[6] = {
 	int32_t ix;
 	GET_FLOAT_WORD(ix,x);
 	ix &= 0x7fffffff;
+        assert(ix>=0x40000000 && ix<=0x48000000);
 	if(ix>=0x41000000)     {p = qR8; q= qS8;}
 	else if(ix>=0x40f71c58){p = qR5; q= qS5;}
 	else if(ix>=0x4036db68){p = qR3; q= qS3;}
diff --git a/src/e_j1.c b/src/e_j1.c
index a1007eb..b084dd9 100644
--- a/src/e_j1.c
+++ b/src/e_j1.c
@@ -11,6 +11,8 @@
  * ====================================================
  */
 
+#include <assert.h>
+
 #include "cdefs-compat.h"
 //__FBSDID("$FreeBSD: src/lib/msun/src/e_j1.c,v 1.9 2008/02/22 02:30:35 das Exp $");
 
@@ -270,6 +272,7 @@ static const double ps2[5] = {
         int32_t ix;
 	GET_HIGH_WORD(ix,x);
 	ix &= 0x7fffffff;
+        assert(ix>=0x40000000 && ix<=0x48000000);
         if(ix>=0x40200000)     {p = pr8; q= ps8;}
         else if(ix>=0x40122E8B){p = pr5; q= ps5;}
         else if(ix>=0x4006DB6D){p = pr3; q= ps3;}
@@ -367,6 +370,7 @@ static const double qs2[6] = {
 	int32_t ix;
 	GET_HIGH_WORD(ix,x);
 	ix &= 0x7fffffff;
+        assert(ix>=0x40000000 && ix<=0x48000000);
 	if(ix>=0x40200000)     {p = qr8; q= qs8;}
 	else if(ix>=0x40122E8B){p = qr5; q= qs5;}
 	else if(ix>=0x4006DB6D){p = qr3; q= qs3;}
diff --git a/src/e_j1f.c b/src/e_j1f.c
index ef38a01..c103f2e 100644
--- a/src/e_j1f.c
+++ b/src/e_j1f.c
@@ -13,6 +13,8 @@
  * ====================================================
  */
 
+#include <assert.h>
+
 #include "cdefs-compat.h"
 //__FBSDID("$FreeBSD: src/lib/msun/src/e_j1f.c,v 1.8 2008/02/22 02:30:35 das Exp $");
 
@@ -227,6 +229,7 @@ static const float ps2[5] = {
         int32_t ix;
 	GET_FLOAT_WORD(ix,x);
 	ix &= 0x7fffffff;
+        assert(ix>=0x40000000 && ix<=0x48000000);
         if(ix>=0x41000000)     {p = pr8; q= ps8;}
         else if(ix>=0x40f71c58){p = pr5; q= ps5;}
         else if(ix>=0x4036db68){p = pr3; q= ps3;}
@@ -324,6 +327,7 @@ static const float qs2[6] = {
 	int32_t ix;
 	GET_FLOAT_WORD(ix,x);
 	ix &= 0x7fffffff;
+        assert(ix>=0x40000000 && ix<=0x48000000);
 	if(ix>=0x40200000)     {p = qr8; q= qs8;}
 	else if(ix>=0x40f71c58){p = qr5; q= qs5;}
 	else if(ix>=0x4036db68){p = qr3; q= qs3;}