diff --git a/src/include/missing_math.h b/src/include/missing_math.h
index fb7009ba8..083f0ca1e 100644
--- a/src/include/missing_math.h
+++ b/src/include/missing_math.h
@@ -8,7 +8,7 @@ Copyright 1999 Emmanuel Rouat
 #ifndef MISSING_MATH_H_INCLUDED
 #define MISSING_MATH_H_INCLUDED
 
-bool AlmostEqualUlps(float, float, int);
+bool AlmostEqualUlps(double, double, long int);
 
 #ifndef HAVE_ERFC
 extern double erfc(double);
diff --git a/src/misc/missing_math.c b/src/misc/missing_math.c
index 2566f8695..f3e2009c5 100644
--- a/src/misc/missing_math.c
+++ b/src/misc/missing_math.c
@@ -13,15 +13,15 @@ $Id$
 
 /* Initial AlmostEqualULPs version - fast and simple, but */
 /* some limitations. */
-bool AlmostEqualUlps(float A, float B, int maxUlps)
+bool AlmostEqualUlps(double A, double B, long int maxUlps)
 {
-    int intDiff;
-    assert(sizeof(float) == sizeof(int));
+    long int intDiff;
+    assert(sizeof(double) == sizeof(long int));
 
     if (A == B)
         return TRUE;
 
-    intDiff = abs(*(int*)&A - *(int*)&B);
+    intDiff = abs(*(long int*)&A - *(long int*)&B);
 
     if (intDiff <= maxUlps)
         return TRUE;
diff --git a/src/misc/missing_math.h b/src/misc/missing_math.h
index 6b479d37b..51dae70a9 100644
--- a/src/misc/missing_math.h
+++ b/src/misc/missing_math.h
@@ -6,7 +6,7 @@
 #ifndef MISSING_MATH_H_INCLUDED
 #define MISSING_MATH_H_INCLUDED
 
-bool AlmostEqualUlps(float, float, int);
+bool AlmostEqualUlps(double, double, long int);
 
 #ifndef HAVE_ERFC
 double erfc(double);