diff --git a/src/ikarus.boot b/src/ikarus.boot
index 094a786..fcd3700 100644
Binary files a/src/ikarus.boot and b/src/ikarus.boot differ
diff --git a/src/ikarus.fixnums.ss b/src/ikarus.fixnums.ss
index 3627dbe..7d76d33 100644
--- a/src/ikarus.fixnums.ss
+++ b/src/ikarus.fixnums.ss
@@ -5,7 +5,7 @@
           fxremainder fxmodulo fxlogor fxlogand fxlogxor fxsll fxsra
           fx= fx< fx<= fx> fx>= 
           fx=? fx<? fx<=? fx>? fx>=? 
-          fxior fxand fxxor fxnot
+          fxior fxand fxxor fxnot fxif
           fxpositive? fxnegative?
           fxeven? fxodd?
           fixnum->string 
@@ -22,7 +22,7 @@
             fxquotient fxremainder fxmodulo fxlogor fxlogand
             fxlogxor fxsll fxsra fx= fx< fx<= fx> fx>=
             fx=? fx<? fx<=? fx>? fx>=? 
-            fxior fxand fxxor fxnot
+            fxior fxand fxxor fxnot fxif
             fxpositive? fxnegative?
             fxeven? fxodd?
             fxarithmetic-shift-left fxarithmetic-shift-right fxarithmetic-shift
@@ -89,6 +89,7 @@
         (error 'fx* "~s is not a fixnum" y))
       ($fx* x y)))
   
+
   (define false-loop
     (lambda (who ls)
       (if (pair? ls) 
@@ -202,6 +203,17 @@
   (define fxand (fxbitop fxand $fxlogand -1))
   (define fxxor (fxbitop fxxor $fxlogxor 0))
   
+  (define (fxif x y z)
+    (if (fixnum? x)
+        (if (fixnum? y) 
+            (if (fixnum? z) 
+                ($fxlogor 
+                  ($fxlogand x y) 
+                  ($fxlogand ($fxlognot x) z))
+                (error 'fxif "~s is not a fixnum" z))
+            (error 'fxif "~s is not a fixnum" y))
+        (error 'fxif "~s is not a fixnum" x)))
+
   (define fxsra
     (lambda (x y) 
       (unless (fixnum? x)
diff --git a/src/makefile.ss b/src/makefile.ss
index f48af9b..6e46d96 100755
--- a/src/makefile.ss
+++ b/src/makefile.ss
@@ -450,6 +450,7 @@
     [fxand i]
     [fxxor i]
     [fxnot i]
+    [fxif i]
     [fxeven?  i]
     [fxodd?   i]
     [fxpositive? i]
diff --git a/src/todo-r6rs.ss b/src/todo-r6rs.ss
index 11ec4d8..9603de0 100755
--- a/src/todo-r6rs.ss
+++ b/src/todo-r6rs.ss
@@ -286,7 +286,7 @@
     [fxdiv0-and-mod0                            D fx]
     [fxeven?                                    C fx]
     [fxfirst-bit-set                            D fx]
-    [fxif                                       D fx]
+    [fxif                                       C fx]
     [fxior                                      C fx]
     [fxlength                                   D fx]
     [fxmax                                      C fx]