diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+# Version 0.4.2
+
+-   fix OSX compilation
+
 # Version 0.4.1
 
 -   fix a bug which caused segmentation fault if a compiled function was called multiple times
diff --git a/CodeGen/X86/CallConv.hs b/CodeGen/X86/CallConv.hs
--- a/CodeGen/X86/CallConv.hs
+++ b/CodeGen/X86/CallConv.hs
@@ -20,7 +20,7 @@
 callFun :: Operand RW S64 -> FunPtr a -> Code
 callFun r p = do
     sub rsp 32
-    mov r (imm $ ptrToIntPtr $ castFunPtrToPtr p)
+    mov r (fromIntegral $ ptrToIntPtr $ castFunPtrToPtr p)
     call r
     add rsp 32
 
@@ -31,10 +31,10 @@
 callFun r p = do
     push r15              -- we will use r15 (non-volatile) to store old rsp
     mov r15 15            -- 0xf
-    not r15               -- 0xffff ... fff0
-    and r15 rsp           -- align rsp into r15
+    not_ r15              -- 0xffff ... fff0
+    and_ r15 rsp          -- align rsp into r15
     xchg r15 rsp          -- new rsp = aligned, r15 = old rsp
-    mov r (imm $ ptrToIntPtr $ castFunPtrToPtr p)
+    mov r (fromIntegral $ ptrToIntPtr $ castFunPtrToPtr p)
     call r
     mov rsp r15           -- restore rsp
     pop r15               -- restore r15
diff --git a/x86-64bit.cabal b/x86-64bit.cabal
--- a/x86-64bit.cabal
+++ b/x86-64bit.cabal
@@ -1,5 +1,5 @@
 name:                x86-64bit
-version:             0.4.1
+version:             0.4.2
 homepage:            https://github.com/divipp/x86-64
 synopsis:            Runtime code generation for x86 64 bit machine code
 description:         The primary goal of x86-64bit is to provide a lightweight assembler for machine generated 64 bit x86 assembly instructions. See README.md for further details.