diff --git a/CHANGELOG b/CHANGELOG
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,8 +1,13 @@
-2019-12-23 Frank Dedden <dev@dedden.net>
+2020-03-30
+        * Version bump (3.1.2)
+        * Fixed bug where stream buffers are updated too soon. (#21)
+        * Updated description of cabal package. (#17)
+
+2019-12-23
         * Version bump (3.1.1).
         * Fixed bug with constant structs and arrays.(#13).
 
-2019-11-22 Ivan Perez <ivan.perez@nianet.org>
+2019-11-22
         * Version bump (3.1).
         * Remove ExternFun (#6).
         * Fix bug in code generation for local expression (#15).
diff --git a/copilot-c99.cabal b/copilot-c99.cabal
--- a/copilot-c99.cabal
+++ b/copilot-c99.cabal
@@ -1,22 +1,22 @@
 cabal-version             : >= 1.10
 name                      : copilot-c99
-version                   : 3.1.1
+version                   : 3.1.2
 synopsis                  : A compiler for Copilot targeting C99.
 description               :
   This package is a back-end from Copilot to C.
   .
   Copilot is a stream (i.e., infinite lists) domain-specific language (DSL) in
   Haskell that compiles into embedded C.  Copilot contains an interpreter,
-  multiple back-end compilers, and other verification tools.  A tutorial, bug
-  reports, and todos are available at
-  <https://github.com/Copilot-Language/copilot-discussion>.
+  multiple back-end compilers, and other verification tools.
   .
-  Examples are available at
-  <https://github.com/Copilot-Language/Copilot/tree/master/Examples>.
+  A tutorial, examples, and other information are available at
+  <https://copilot-language.github.io>.
 
 license                   : BSD3
 license-file              : LICENSE
 maintainer                : Frank Dedden <dev@dedden.net>
+homepage                  : https://copilot-language.github.io
+bug-reports               : https://github.com/Copilot-Language/copilot-c99/issues
 stability                 : Experimental
 category                  : Language, Embedded
 build-type                : Simple
diff --git a/src/Copilot/Compile/C99/CodeGen.hs b/src/Copilot/Compile/C99/CodeGen.hs
--- a/src/Copilot/Compile/C99/CodeGen.hs
+++ b/src/Copilot/Compile/C99/CodeGen.hs
@@ -4,7 +4,7 @@
 module Copilot.Compile.C99.CodeGen where
 
 import Control.Monad.State  (runState)
-import Data.List            (union)
+import Data.List            (union, unzip4)
 import Data.Typeable        (Typeable)
 
 import qualified Language.C99.Simple as C
@@ -56,12 +56,45 @@
 mkstep :: [Stream] -> [Trigger] -> [External] -> C.FunDef
 mkstep streams triggers exts = C.FunDef void "step" [] declns stmts where
   void = C.TypeSpec C.Void
-  declns = []
   stmts  =  map mkexcopy exts
          ++ map mktriggercheck triggers
-         ++ map mkupdatebuffer streams
-         ++ map mkupdateindex streams
+         ++ tmpassigns
+         ++ bufferupdates
+         ++ indexupdates
+  (declns, tmpassigns, bufferupdates, indexupdates) =
+    unzip4 $ map mkupdateglobals streams
 
+  -- Write code to update global stream buffers and index.
+  mkupdateglobals :: Stream -> (C.Decln, C.Stmt, C.Stmt, C.Stmt)
+  mkupdateglobals (Stream sid buff expr ty) =
+    (tmpdecln, tmpassign, bufferupdate, indexupdate)
+      where
+        tmpdecln = C.VarDecln Nothing cty tmp_var Nothing
+
+        tmpassign = case ty of
+          Array _ -> C.Expr $ memcpy (C.Ident tmp_var) val size
+            where
+              size = C.LitInt $ fromIntegral $ tysize ty
+          _       -> C.Expr $ C.Ident tmp_var C..= val
+
+        bufferupdate = case ty of
+          Array _ -> C.Expr $ memcpy dest (C.Ident tmp_var) size
+            where
+              dest = C.Index buff_var index_var
+              size = C.LitInt $ fromIntegral $ tysize ty
+          _       -> C.Expr $ C.Index buff_var index_var C..= (C.Ident tmp_var)
+
+        indexupdate = C.Expr $ index_var C..= (incindex C..% bufflength)
+          where
+            bufflength = C.LitInt $ fromIntegral $ length buff
+            incindex   = (C..++) index_var
+
+        tmp_var   = streamname sid ++ "_tmp"
+        buff_var  = C.Ident $ streamname sid
+        index_var = C.Ident $ indexname sid
+        val       = C.Funcall (C.Ident $ generatorname sid) []
+        cty       = transtype ty
+
   -- Make code that copies an external variable to its local one.
   mkexcopy :: External -> C.Stmt
   mkexcopy (External name cpyname ty) = C.Expr $ case ty of
@@ -78,26 +111,6 @@
     firetrigger = [C.Expr $ C.Funcall (C.Ident name) args'] where
       args'        = take (length args) (map argcall (argnames name))
       argcall name = C.Funcall (C.Ident name) []
-
-  -- Code to update the global buffer.
-  mkupdatebuffer :: Stream -> C.Stmt
-  mkupdatebuffer (Stream sid buff expr ty) = case ty of
-    Array _ -> C.Expr $ memcpy dest src size where
-      dest = C.Index (C.Ident $ streamname sid) (C.Ident $ indexname sid)
-      src  = C.Funcall (C.Ident $ generatorname sid) []
-      size = C.LitInt $ fromIntegral $ tysize ty
-    _ -> C.Expr $ C.Index var index C..= val where
-      var   = C.Ident $ streamname sid
-      index = C.Ident $ indexname sid
-      val   = C.Funcall (C.Ident $ generatorname sid) []
-
-  -- Code to update the index.
-  mkupdateindex :: Stream -> C.Stmt
-  mkupdateindex (Stream sid buff expr ty) = C.Expr $ globvar C..= val where
-    globvar = C.Ident $ indexname sid
-    index   = (C..++) (C.Ident $ indexname sid)
-    val     = index C..% (C.LitInt $ fromIntegral len)
-    len     = length buff
 
   -- Write a call to the memcpy function.
   memcpy :: C.Expr -> C.Expr -> C.Expr -> C.Expr