diff --git a/Changelog.md b/Changelog.md
--- a/Changelog.md
+++ b/Changelog.md
@@ -1,3 +1,7 @@
+## 0.3.7.1
+
+* Fix x32 build
+
 ## 0.3.7
 
 * Significant performance improvements
diff --git a/Data/Unicode/Internal/Bits.hs b/Data/Unicode/Internal/Bits.hs
--- a/Data/Unicode/Internal/Bits.hs
+++ b/Data/Unicode/Internal/Bits.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE BangPatterns #-}
 {-# LANGUAGE MagicHash #-}
 -- |
 -- Module      : Data.Unicode.Internal.Bits
@@ -16,8 +17,9 @@
       lookupBit64
     ) where
 
+import Data.Bits (finiteBitSize, popCount)
 import GHC.Exts
-       (Addr#, Int(..), Word(..), indexWord64OffAddr#, and#, andI#,
+       (Addr#, Int(..), Word(..), indexWordOffAddr#, and#, andI#,
         uncheckedIShiftRL#, uncheckedShiftL#)
 
 -- | @lookup64 addr index@ looks up the bit stored at bit index @index@ using a
@@ -29,7 +31,13 @@
 lookupBit64 :: Addr# -> Int -> Bool
 lookupBit64 addr# (I# index#) = W# (word## `and#` bitMask##) /= 0
   where
-    wordIndex# = index# `uncheckedIShiftRL#` 6#
-    word## = indexWord64OffAddr# addr# wordIndex#
-    bitIndex# = index# `andI#` 63#
+    !fbs@(I# fbs#) = finiteBitSize (0 :: Word) - 1
+    !(I# logFbs#) = case fbs of
+      31 -> 5
+      63 -> 6
+      _  -> popCount fbs -- this is a really weird architecture
+
+    wordIndex# = index# `uncheckedIShiftRL#` logFbs#
+    word## = indexWordOffAddr# addr# wordIndex#
+    bitIndex# = index# `andI#` fbs#
     bitMask## = 1## `uncheckedShiftL#` bitIndex#
diff --git a/unicode-transforms.cabal b/unicode-transforms.cabal
--- a/unicode-transforms.cabal
+++ b/unicode-transforms.cabal
@@ -1,13 +1,13 @@
 cabal-version: 2.2
 
 name:           unicode-transforms
-version:        0.3.7
+version:        0.3.7.1
 synopsis:       Unicode normalization
 description:    Fast Unicode 13.0.0 normalization in Haskell (NFC, NFKC, NFD, NFKD).
 category:       Data,Text,Unicode
 stability:      Experimental
-homepage:       http://github.com/harendra-kumar/unicode-transforms
-bug-reports:    https://github.com/harendra-kumar/unicode-transforms/issues
+homepage:       http://github.com/composewell/unicode-transforms
+bug-reports:    https://github.com/composewell/unicode-transforms/issues
 author:         Harendra Kumar
 maintainer:     harendra.kumar@gmail.com
 copyright:      2016-2017 Harendra Kumar,
@@ -51,7 +51,7 @@
 
 source-repository head
   type: git
-  location: https://github.com/harendra-kumar/unicode-transforms
+  location: https://github.com/composewell/unicode-transforms
 
 flag dev
   description: Developer build
@@ -96,7 +96,7 @@
   ghc-options: -Wall -fwarn-identities -fwarn-incomplete-record-updates -fwarn-incomplete-uni-patterns -fwarn-tabs
   build-depends:
       base >=4.7 && <5
-    , bytestring >=0.9 && <0.11
+    , bytestring >=0.9 && <0.12
     , text >=1.1.1 && <1.3
     , ghc-prim >= 0.2 && < 0.7
   if flag(dev)