diff --git a/src/gf.c b/src/gf.c
index 835fb12..b9caa26 100644
--- a/src/gf.c
+++ b/src/gf.c
@@ -219,7 +219,7 @@ int gf_error_check(int w, int mult_type, int region_type, int divide_type,
 #endif
 
 #ifdef ARM_NEON
-  pclmul = 1;
+  pclmul = (w == 4 || w == 8);
   sse3 = 1;
 #endif
 
diff --git a/src/neon/gf_w16_neon.c b/src/neon/gf_w16_neon.c
index 95bfd80..2bd3f30 100644
--- a/src/neon/gf_w16_neon.c
+++ b/src/neon/gf_w16_neon.c
@@ -46,7 +46,11 @@
 #include <stdlib.h>
 #include "gf_w16.h"
 
-#ifdef ARCH_AARCH64
+#ifndef ARCH_AARCH64
+#define vqtbl1q_u8(tbl, v) vcombine_u8(vtbl2_u8(tbl, vget_low_u8(v)),   \
+                                       vtbl2_u8(tbl, vget_high_u8(v)))
+#endif
+
 static
 inline
 void
@@ -56,23 +60,32 @@ neon_w16_split_4_multiply_region(gf_t *gf, uint16_t *src, uint16_t *dst,
 {
   unsigned i;
   uint8_t *high = tbl + 4 * 16;
-  uint16x8_t va0, va1, r0, r1;
   uint8x16_t loset, rl, rh;
   uint8x16x2_t va;
 
+#ifdef ARCH_AARCH64
   uint8x16_t tbl_h[4], tbl_l[4];
   for (i = 0; i < 4; i++) {
       tbl_l[i] = vld1q_u8(tbl + i*16);
       tbl_h[i] = vld1q_u8(high + i*16);
   }
+#else
+  uint8x8x2_t tbl_h[4], tbl_l[4];
+  for (i = 0; i < 4; i++) {
+      tbl_l[i].val[0] = vld1_u8(tbl + i*16);
+      tbl_l[i].val[1] = vld1_u8(tbl + i*16 + 8);
+      tbl_h[i].val[0] = vld1_u8(high + i*16);
+      tbl_h[i].val[1] = vld1_u8(high + i*16 + 8);
+  }
+#endif
 
   loset = vdupq_n_u8(0xf);
 
-  while (dst < d_end) {
-      va0 = vld1q_u16(src);
-      va1 = vld1q_u16(src + 8);
-
-      va = vtrnq_u8(vreinterpretq_u8_u16(va0), vreinterpretq_u8_u16(va1));
+  if (xor) {
+    uint8x16x2_t vb;
+    while (dst < d_end) {
+      va = vld2q_u8((uint8_t*)src);
+      vb = vld2q_u8((uint8_t*)dst);
 
       rl = vqtbl1q_u8(tbl_l[0], vandq_u8(va.val[0], loset));
       rh = vqtbl1q_u8(tbl_h[0], vandq_u8(va.val[0], loset));
@@ -84,24 +97,38 @@ neon_w16_split_4_multiply_region(gf_t *gf, uint16_t *src, uint16_t *dst,
 
       rl = veorq_u8(rl, vqtbl1q_u8(tbl_l[1], va.val[0]));
       rh = veorq_u8(rh, vqtbl1q_u8(tbl_h[1], va.val[0]));
-      rl = veorq_u8(rl, vqtbl1q_u8(tbl_l[3], va.val[1]));
-      rh = veorq_u8(rh, vqtbl1q_u8(tbl_h[3], va.val[1]));
+      va.val[0] = veorq_u8(rl, vqtbl1q_u8(tbl_l[3], va.val[1]));
+      va.val[1] = veorq_u8(rh, vqtbl1q_u8(tbl_h[3], va.val[1]));
 
-      va = vtrnq_u8(rl, rh);
-      r0 = vreinterpretq_u16_u8(va.val[0]);
-      r1 = vreinterpretq_u16_u8(va.val[1]);
-
-      if (xor) {
-          va0 = vld1q_u16(dst);
-          va1 = vld1q_u16(dst + 8);
-          r0 = veorq_u16(r0, va0);
-          r1 = veorq_u16(r1, va1);
-      }
-      vst1q_u16(dst, r0);
-      vst1q_u16(dst + 8, r1);
+      va.val[0] = veorq_u8(va.val[0], vb.val[0]);
+      va.val[1] = veorq_u8(va.val[1], vb.val[1]);
+      vst2q_u8((uint8_t*)dst, va);
 
       src += 16;
       dst += 16;
+    }
+  } else {
+    while (dst < d_end) {
+      va = vld2q_u8((uint8_t*)src);
+
+      rl = vqtbl1q_u8(tbl_l[0], vandq_u8(va.val[0], loset));
+      rh = vqtbl1q_u8(tbl_h[0], vandq_u8(va.val[0], loset));
+      rl = veorq_u8(rl, vqtbl1q_u8(tbl_l[2], vandq_u8(va.val[1], loset)));
+      rh = veorq_u8(rh, vqtbl1q_u8(tbl_h[2], vandq_u8(va.val[1], loset)));
+
+      va.val[0] = vshrq_n_u8(va.val[0], 4);
+      va.val[1] = vshrq_n_u8(va.val[1], 4);
+
+      rl = veorq_u8(rl, vqtbl1q_u8(tbl_l[1], va.val[0]));
+      rh = veorq_u8(rh, vqtbl1q_u8(tbl_h[1], va.val[0]));
+      va.val[0] = veorq_u8(rl, vqtbl1q_u8(tbl_l[3], va.val[1]));
+      va.val[1] = veorq_u8(rh, vqtbl1q_u8(tbl_h[3], va.val[1]));
+
+      vst2q_u8((uint8_t*)dst, va);
+
+      src += 16;
+      dst += 16;
+    }
   }
 }
 
@@ -118,10 +145,21 @@ neon_w16_split_4_altmap_multiply_region(gf_t *gf, uint8_t *src,
   uint8x16_t vh, vl, rh, rl;
   uint8x16_t loset;
 
+#ifdef ARCH_AARCH64
   uint8x16_t tbl_h[4], tbl_l[4];
+#else
+  uint8x8x2_t tbl_h[4], tbl_l[4];
+#endif
   for (i = 0; i < 4; i++) {
+#ifdef ARCH_AARCH64
       tbl_l[i] = vld1q_u8(tbl + i*16);
       tbl_h[i] = vld1q_u8(high + i*16);
+#else
+      tbl_l[i].val[0] = vld1_u8(tbl + i*16);
+      tbl_l[i].val[1] = vld1_u8(tbl + i*16 + 8);
+      tbl_h[i].val[0] = vld1_u8(high + i*16);
+      tbl_h[i].val[1] = vld1_u8(high + i*16 + 8);
+#endif
   }
 
   loset = vdupq_n_u8(0xf);
@@ -157,125 +195,7 @@ neon_w16_split_4_altmap_multiply_region(gf_t *gf, uint8_t *src,
   }
 }
 
-#else /* ARCH_AARCH64 */
 
-static
-inline
-void
-neon_w16_split_4_multiply_region(gf_t *gf, uint16_t *src, uint16_t *dst,
-                                 uint16_t *d_end, uint8_t *tbl,
-                                 gf_val_32_t val, int xor)
-{
-  unsigned i;
-  uint8_t *high = tbl + 4 * 16;
-  uint16x8_t va, r;
-  uint8x8_t loset, vb, vc, rl, rh;
-
-  uint8x8x2_t tbl_h[4], tbl_l[4];
-  for (i = 0; i < 4; i++) {
-      tbl_l[i].val[0] = vld1_u8(tbl + i*16);
-      tbl_l[i].val[1] = vld1_u8(tbl + i*16 + 8);
-      tbl_h[i].val[0] = vld1_u8(high + i*16);
-      tbl_h[i].val[1] = vld1_u8(high + i*16 + 8);
-  }
-
-  loset = vdup_n_u8(0xf);
-
-  while (dst < d_end) {
-      va = vld1q_u16(src);
-
-      vb = vmovn_u16(va);
-      vc = vshrn_n_u16(va, 8);
-
-      rl = vtbl2_u8(tbl_l[0], vand_u8(vb, loset));
-      rh = vtbl2_u8(tbl_h[0], vand_u8(vb, loset));
-      vb = vshr_n_u8(vb, 4);
-      rl = veor_u8(rl, vtbl2_u8(tbl_l[2], vand_u8(vc, loset)));
-      rh = veor_u8(rh, vtbl2_u8(tbl_h[2], vand_u8(vc, loset)));
-      vc = vshr_n_u8(vc, 4);
-      rl = veor_u8(rl, vtbl2_u8(tbl_l[1], vb));
-      rh = veor_u8(rh, vtbl2_u8(tbl_h[1], vb));
-      rl = veor_u8(rl, vtbl2_u8(tbl_l[3], vc));
-      rh = veor_u8(rh, vtbl2_u8(tbl_h[3], vc));
-
-      r  = vmovl_u8(rl);
-      r  = vorrq_u16(r, vshll_n_u8(rh, 8));
-
-      if (xor) {
-          va = vld1q_u16(dst);
-          r = veorq_u16(r, va);
-      }
-      vst1q_u16(dst, r);
-
-      src += 8;
-      dst += 8;
-  }
-}
-
-static
-inline
-void
-neon_w16_split_4_altmap_multiply_region(gf_t *gf, uint8_t *src,
-                                        uint8_t *dst, uint8_t *d_end,
-                                        uint8_t *tbl, gf_val_32_t val,
-                                        int xor)
-{
-  unsigned i;
-  uint8_t *high = tbl + 4 * 16;
-  uint8x8_t vh0, vh1, vl0, vl1, r0, r1, r2, r3;
-  uint8x8_t loset;
-
-  uint8x8x2_t tbl_h[4], tbl_l[4];
-  for (i = 0; i < 4; i++) {
-      tbl_l[i].val[0] = vld1_u8(tbl + i*16);
-      tbl_l[i].val[1] = vld1_u8(tbl + i*16 + 8);
-      tbl_h[i].val[0] = vld1_u8(high + i*16);
-      tbl_h[i].val[1] = vld1_u8(high + i*16 + 8);
-  }
-
-  loset = vdup_n_u8(0xf);
-
-  while (dst < d_end) {
-      vh0 = vld1_u8(src);
-      vh1 = vld1_u8(src + 8);
-      vl0 = vld1_u8(src + 16);
-      vl1 = vld1_u8(src + 24);
-
-      r0 = vtbl2_u8(tbl_l[0], vand_u8(vh0, loset));
-      r1 = vtbl2_u8(tbl_h[0], vand_u8(vh1, loset));
-      r2 = vtbl2_u8(tbl_l[2], vand_u8(vl0, loset));
-      r3 = vtbl2_u8(tbl_h[2], vand_u8(vl1, loset));
-
-      vh0 = vshr_n_u8(vh0, 4);
-      vh1 = vshr_n_u8(vh1, 4);
-      vl0 = vshr_n_u8(vl0, 4);
-      vl1 = vshr_n_u8(vl1, 4);
-
-      r0 = veor_u8(r0, vtbl2_u8(tbl_l[1], vh0));
-      r1 = veor_u8(r1, vtbl2_u8(tbl_h[1], vh1));
-      r2 = veor_u8(r2, vtbl2_u8(tbl_l[3], vl0));
-      r3 = veor_u8(r3, vtbl2_u8(tbl_h[3], vl1));
-
-      if (xor) {
-          vh0 = vld1_u8(dst);
-          vh1 = vld1_u8(dst + 8);
-          vl0 = vld1_u8(dst + 16);
-          vl1 = vld1_u8(dst + 24);
-          r0  = veor_u8(r0, vh0);
-          r1  = veor_u8(r1, vh1);
-          r2  = veor_u8(r2, vl0);
-          r3  = veor_u8(r3, vl1);
-      }
-      vst1_u8(dst,      r0);
-      vst1_u8(dst +  8, r1);
-      vst1_u8(dst + 16, r2);
-      vst1_u8(dst + 24, r3);
-
-      src += 32;
-      dst += 32;
-  }
-}
-#endif /* ARCH_AARCH64 */
 
 static
 inline