diff --git a/bin/ikarus b/bin/ikarus
index 29640ed..6f3d8bb 100755
Binary files a/bin/ikarus and b/bin/ikarus differ
diff --git a/bin/ikarus-flonums.c b/bin/ikarus-flonums.c
index f24832f..27c2337 100644
--- a/bin/ikarus-flonums.c
+++ b/bin/ikarus-flonums.c
@@ -150,48 +150,6 @@ ikrt_fixnum_to_flonum(ikp x, ikpcb* pcb){
   return r;
 }
 
-ikp
-ikrt_bignum_to_flonum(ikp x, ikpcb* pcb){
-  ikp r = ik_alloc(pcb, flonum_size) + vector_tag;
-  ref(r, -vector_tag) = (ikp)flonum_tag;
-  unsigned int fst = (unsigned int) ref(x, -vector_tag);
-  int limbs = (fst >> bignum_length_shift);
-  double fl;
-  if(limbs == 1){
-    fl = ((unsigned int)ref(x, disp_bignum_data - vector_tag));
-  } else if(limbs == 2){
-    fl = ((unsigned int)ref(x, wordsize+disp_bignum_data - vector_tag));
-    fl *= exp2(32);
-    fl += ((unsigned int)ref(x, disp_bignum_data - vector_tag));
-  } else {
-    fl = 
-      ((unsigned int)ref(x, limbs * wordsize - wordsize + 
-                            disp_bignum_data - vector_tag));
-    fl *= exp2(32);
-    fl += ((unsigned int)ref(x, limbs * wordsize - (wordsize*2) +
-                                disp_bignum_data - vector_tag));
-    fl *= exp2(32);
-    fl += ((unsigned int)ref(x, limbs * wordsize - (wordsize*3) +
-                                disp_bignum_data - vector_tag));
-    fl *= exp2(limbs*wordsize*8-wordsize*8*3);
-  }
-  if((fst & bignum_sign_mask) != 0){
-    fl = -fl;
-  }
-  flonum_data(r) = fl;
-#if 0
-  {
-    int i;
-    unsigned char* p = (unsigned char*)(r+disp_flonum_data-vector_tag);
-    for(i=0; i<8; i++){
-      fprintf(stderr, "%02x ", p[7-i]);
-    }
-    fprintf(stderr, "\n");
-  }
-#endif
-  return r;
-}
-
 ikp
 ikrt_fl_equal(ikp x, ikp y){
   if(flonum_data(x) == flonum_data(y)){
diff --git a/src/ikarus.boot b/src/ikarus.boot
index 9f0cab8..33f679b 100644
Binary files a/src/ikarus.boot and b/src/ikarus.boot differ
diff --git a/src/run-tests.ss b/src/run-tests.ss
index be2931e..a5be1fc 100755
--- a/src/run-tests.ss
+++ b/src/run-tests.ss
@@ -2,7 +2,8 @@
 
 (import (ikarus)
         (tests reader)
-        (tests bytevectors))
+        (tests bytevectors)
+        (tests bignum-to-flonum))
 
 (define (test-exact-integer-sqrt)
   (define (f i j inc)
@@ -20,4 +21,5 @@
 (test-reader)
 (test-bytevectors)
 (test-exact-integer-sqrt)
+(test-bignum-to-flonum)
 (printf "Happy Happy Joy Joy\n")
diff --git a/src/tests/bignum-to-flonum.ss b/src/tests/bignum-to-flonum.ss
new file mode 100644
index 0000000..a0ed877
--- /dev/null
+++ b/src/tests/bignum-to-flonum.ss
@@ -0,0 +1,54 @@
+
+(library (tests bignum-to-flonum)
+  (export test-bignum-to-flonum)
+  (import (ikarus) (tests framework))
+  (define (t x s)
+    (let ([fl (format "~a" (exact->inexact x))])
+      (unless (string=? s fl)
+        (error 'bignum->flonum
+          "incorrect result for ~s\n expected ~a, \n      got ~a" x s fl))))
+  (define-syntax test*
+    (syntax-rules ()
+      [(_ name [num str] ...)
+       (define-tests name 
+         [(lambda (x) (string=? str (number->string x))) (exact->inexact num)]
+         ...)]))
+  (test* test-bignum-to-flonum
+    (1000000000  "1e9")
+    (2000000000  "2e9")
+    (4000000000  "4e9")
+    (-1000000000 "-1e9")
+    (-2000000000 "-2e9")
+    (-4000000000 "-4e9")
+    ( 6000000000   "6e9")
+    (12000000000 "1.2e10")
+    (25000000000 "2.5e10")
+    (50000000000   "5e10")
+    (-6000000000  "-6e9")
+    (-12000000000 "-1.2e10")
+    (-25000000000 "-2.5e10")
+    (-50000000000 "-5e10")
+    (100000000000 "1e11")
+    (200000000000 "2e11")
+    (400000000000 "4e11")
+    (800000000000 "8e11")
+    (-100000000000 "-1e11")
+    (-200000000000 "-2e11")
+    (-400000000000 "-4e11")
+    (-800000000000 "-8e11")
+    (#x1FFFFFFFFFFFFF   "9.007199254740991e15")
+    (#x3FFFFFFFFFFFFF   "1.8014398509481984e16")
+    (#x7FFFFFFFFFFFFF   "3.602879701896397e16")
+    (#xFFFFFFFFFFFFFF   "7.205759403792794e16")
+    (#x1FFFFFFFFFFFFFF  "1.4411518807585587e17")
+    (#x3FFFFFFFFFFFFFF  "2.8823037615171174e17")
+    (#x7FFFFFFFFFFFFFF  "5.764607523034235e17")
+    (#xFFFFFFFFFFFFFFF  "1.152921504606847e18")
+    (#xFFFFFFFFFFFFFFFF "1.8446744073709552e19")
+    (1000000000000000000000 "1e21")
+    (100000000000000000000000000000 "1e29")
+    (100000000000000000000000000000000000000000000000 "1e47")
+    (-1000000000000000000000 "-1e21")
+    (-100000000000000000000000000000 "-1e29")
+    (-100000000000000000000000000000000000000000000000 "-1e47")))
+