diff --git a/Python/dtoa.c b/Python/dtoa.c
index da6b7e04045..12e6f806380 100644
--- a/Python/dtoa.c
+++ b/Python/dtoa.c
@@ -200,6 +200,13 @@ typedef union { double d; ULong L[2]; } U;
 #define STRTOD_DIGLIM 40
 #endif
 
+/* maximum permitted exponent value for strtod; exponents larger than
+   MAX_ABS_EXP in absolute value get truncated to +-MAX_ABS_EXP.  MAX_ABS_EXP
+   should fit into an int. */
+#ifndef MAX_ABS_EXP
+#define MAX_ABS_EXP 19999U
+#endif
+
 /* The following definition of Storeinc is appropriate for MIPS processors.
  * An alternative that might be better on some machines is
  * #define Storeinc(a,b,c) (*a++ = b << 16 | c & 0xffff)
@@ -1305,9 +1312,8 @@ _Py_dg_strtod(const char *s00, char **se)
     int esign, i, j, k, nd, nd0, nf, nz, nz0, sign;
     const char *s, *s0, *s1;
     double aadj, aadj1;
-    Long L;
     U aadj2, adj, rv, rv0;
-    ULong y, z;
+    ULong y, z, L;
     BCinfo bc;
     Bigint *bb, *bb1, *bd, *bd0, *bs, *delta;
 
@@ -1406,11 +1412,11 @@ _Py_dg_strtod(const char *s00, char **se)
                 s1 = s;
                 while((c = *++s) >= '0' && c <= '9')
                     L = 10*L + c - '0';
-                if (s - s1 > 8 || L > 19999)
+                if (s - s1 > 8 || L > MAX_ABS_EXP)
                     /* Avoid confusion from exponents
                      * so large that e might overflow.
                      */
-                    e = 19999; /* safe for 16 bit ints */
+                    e = (int)MAX_ABS_EXP; /* safe for 16 bit ints */
                 else
                     e = (int)L;
                 if (esign)