diff --git a/miniz_tdef.c b/miniz_tdef.c
index 8dc33cd..6f40934 100644
--- a/miniz_tdef.c
+++ b/miniz_tdef.c
@@ -521,7 +521,7 @@ static mz_bool tdefl_compress_lz_codes(tdefl_compressor *d)
         if (pOutput_buf >= d->m_pOutput_buf_end)
             return MZ_FALSE;
 
-        memcpy(pOutput_buf, &bit_buffer, 8);
+        memcpy(pOutput_buf, &bit_buffer, sizeof(mz_uint64));
         pOutput_buf += (bits_in >> 3);
         bit_buffer >>= (bits_in & ~7);
         bits_in &= 7;