diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,5 @@
+# 0.1.0.1
+- use hsc2hs's #alignment macro in Storable instances
+
+# 0.1.0.0
+- initial release
diff --git a/hgmp.cabal b/hgmp.cabal
--- a/hgmp.cabal
+++ b/hgmp.cabal
@@ -1,5 +1,5 @@
 name:                hgmp
-version:             0.1.0.0
+version:             0.1.0.1
 synopsis:            Haskell interface to GMP
 description:         Currently, types and instances, and marshalling between
                      Integer and Rational and the corresponding GMP types.
@@ -19,7 +19,7 @@
 copyright:           2016 Claude Heiland-Allen
 category:            Numeric
 build-type:          Simple
-extra-source-files:  README.md examples/primes.hs
+extra-source-files:  README.md CHANGELOG.md examples/primes.hs
 cabal-version:       >=1.10
 
 library
@@ -56,4 +56,4 @@
 source-repository this
   type:                git
   location:            https://code.mathr.co.uk/hgmp.git
-  tag:                 v0.1.0.0
+  tag:                 v0.1.0.1
diff --git a/src/Numeric/GMP/Types.hsc b/src/Numeric/GMP/Types.hsc
--- a/src/Numeric/GMP/Types.hsc
+++ b/src/Numeric/GMP/Types.hsc
@@ -25,7 +25,7 @@
 
 instance Storable MPZ where
   sizeOf _ = (#size __mpz_struct)
-  alignment _ = alignment nullPtr -- TODO verify
+  alignment _ = (#alignment __mpz_struct)
   peek ptr = do
     alloc <- (#peek __mpz_struct, _mp_alloc) ptr
     size <- (#peek __mpz_struct, _mp_size) ptr
@@ -44,7 +44,7 @@
 
 instance Storable MPQ where
   sizeOf _ = (#size __mpq_struct)
-  alignment _ = alignment (undefined :: MPZ)
+  alignment _ = (#alignment __mpq_struct)
   peek ptr = do
     num <- (#peek __mpq_struct, _mp_num) ptr
     den <- (#peek __mpq_struct, _mp_den) ptr
@@ -68,7 +68,7 @@
 
 instance Storable MPF where
   sizeOf _ = (#size __mpf_struct)
-  alignment _ = alignment nullPtr -- TODO verify
+  alignment _ = (#alignment __mpf_struct)
   peek ptr = do
     prec <- (#peek __mpf_struct, _mp_prec) ptr
     size <- (#peek __mpf_struct, _mp_size) ptr
@@ -90,7 +90,7 @@
 
 instance Storable GMPRandState where
   sizeOf _ = (#size __gmp_randstate_struct)
-  alignment _ = alignment nullPtr -- TOOD verify
+  alignment _ = (#alignment __gmp_randstate_struct)
   peek ptr = do
     seed <- (#peek __gmp_randstate_struct, _mp_seed) ptr
     alg <- (#peek __gmp_randstate_struct, _mp_alg) ptr