diff --git a/src/c/number.d b/src/c/number.d
index 418003c19..1741f2831 100644
--- a/src/c/number.d
+++ b/src/c/number.d
@@ -275,22 +275,6 @@ init_number(void)
 	ECL_SET(@'LEAST-NEGATIVE-NORMALIZED-DOUBLE-FLOAT', num);
 	ECL_SET(@'LEAST-NEGATIVE-NORMALIZED-LONG-FLOAT', num);
 
-	num = make_shortfloat(FLT_EPSILON);
-	ECL_SET(@'SHORT-FLOAT-EPSILON', num);
-	ECL_SET(@'SINGLE-FLOAT-EPSILON', num);
-
-	num = make_shortfloat(-FLT_EPSILON);
-	ECL_SET(@'SHORT-FLOAT-NEGATIVE-EPSILON', num);
-	ECL_SET(@'SINGLE-FLOAT-NEGATIVE-EPSILON', num);
-
-	num = make_longfloat(DBL_EPSILON);
-	ECL_SET(@'DOUBLE-FLOAT-EPSILON', num);
-	ECL_SET(@'LONG-FLOAT-EPSILON', num);
-
-	num = make_longfloat(-DBL_EPSILON);
-	ECL_SET(@'DOUBLE-FLOAT-NEGATIVE-EPSILON', num);
-	ECL_SET(@'LONG-FLOAT-NEGATIVE-EPSILON', num);
-
  	cl_core.shortfloat_zero = cl_alloc_object(t_shortfloat);
  	sf(cl_core.shortfloat_zero) = (float)0.0;
  	cl_core.longfloat_zero = cl_alloc_object(t_longfloat);
diff --git a/src/c/print.d b/src/c/print.d
index 752e09039..94228cd02 100644
--- a/src/c/print.d
+++ b/src/c/print.d
@@ -342,7 +342,7 @@ write_double(double d, int e, bool shortp)
 	int n = FPRC;		/* was FPRC+1 */
 
 	if (shortp)
-		n = 7;
+		n = 8;
 	edit_double(n, d, &sign, buff, &exp);
 	if (sign==2) {
 		write_str("#<");
diff --git a/src/lsp/numlib.lsp b/src/lsp/numlib.lsp
index 32b9cba5e..d74bbb3ef 100644
--- a/src/lsp/numlib.lsp
+++ b/src/lsp/numlib.lsp
@@ -15,6 +15,40 @@
 #-ecl-min
 (ffi:clines "#include <math.h>")
 
+#.
+(flet ((binary-search (f min max)
+	 (do ((new (/ (+ min max) 2) (/ (+ min max) 2)))
+	     ((>= min max)
+	      max)
+	   (if (funcall f new)
+	       (if (= new max)
+		   (return max)
+		   (setq max new))
+	       (if (= new min)
+		   (return max)
+		   (setq min new)))))
+       (epsilon+ (x)
+	 (/= (float 1 x) (+ (float 1 x) x)))
+       (epsilon- (x)
+	 (/= (float 1 x) (- (float 1 x) x))))
+  `(eval-when (compile load eval)
+    (defconstant short-float-epsilon
+      ,(binary-search #'epsilon+ (coerce 0 'short-float) (coerce 1 'short-float)))
+    (defconstant single-float-epsilon
+      ,(binary-search #'epsilon+ (coerce 0 'single-float) (coerce 1 'single-float)))
+    (defconstant long-float-epsilon
+      ,(binary-search #'epsilon+ (coerce 0 'double-float) (coerce 1 'double-float)))
+    (defconstant double-float-epsilon
+      ,(binary-search #'epsilon+ (coerce 0 'long-float) (coerce 1 'long-float)))
+    (defconstant short-float-negative-epsilon
+      ,(binary-search #'epsilon- (coerce 0 'short-float) (coerce 1 'short-float)))
+    (defconstant single-float-negative-epsilon
+      ,(binary-search #'epsilon- (coerce 0 'single-float) (coerce 1 'single-float)))
+    (defconstant long-float-negative-epsilon
+      ,(binary-search #'epsilon- (coerce 0 'double-float) (coerce 1 'double-float)))
+    (defconstant double-float-negative-epsilon
+      ,(binary-search #'epsilon- (coerce 0 'long-float) (coerce 1 'long-float)))))
+
 (defconstant imag-one #C(0.0 1.0))
 
 (defun isqrt (i)