--- /tmp/image-format-conversions.h	2009-02-03 10:18:04.000000000 +0100
+++ git/src/image-format-conversions.h	2009-02-03 10:19:18.000000000 +0100
@@ -30,6 +30,8 @@
 /* Basic C implementation of YV12/I420 to UYVY conversion */
 void uv12_to_uyvy(int w, int h, int y_pitch, int uv_pitch, uint8_t *y_p, uint8_t *u_p, uint8_t *v_p, uint8_t *dest);
 
+/* NEON implementation of YV12/I420 to UYVY conversion */
+void uv12_to_uyvy_neon(int w, int h, int y_pitch, int uv_pitch, uint8_t *y_p, uint8_t *u_p, uint8_t *v_p, uint8_t *dest);
 
 #endif /* __IMAGE_FORMAT_CONVERSIONS_H__ */
 
--- /tmp/image-format-conversions.c	2009-02-03 10:18:04.000000000 +0100
+++ git/src/image-format-conversions.c	2009-02-03 10:16:47.000000000 +0100
@@ -2,6 +2,7 @@
  * Copyright 2008 Kalle Vahlman, <zuh@iki.fi>
  *                Ilpo Ruotsalainen, <lonewolf@iki.fi>
  *                Tuomas Kulve, <tuomas.kulve@movial.com>
+ *                Ian Rickards, <ian.rickards@arm.com>
  *                
  *
  * Permission to use, copy, modify, distribute and sell this software and its
@@ -89,3 +90,104 @@
 	}
 }
 
+void uv12_to_uyvy_neon(int w, int h, int y_pitch, int uv_pitch, uint8_t *y_p, uint8_t *u_p, uint8_t *v_p, uint8_t *dest)
+{
+    int x, y;
+    uint8_t *dest_even = dest;
+    uint8_t *dest_odd = dest + w * 2;
+    uint8_t *y_p_even = y_p;
+    uint8_t *y_p_odd = y_p + y_pitch;
+
+    /*ErrorF("in uv12_to_uyvy, w: %d, pitch: %d\n", w, pitch);*/
+    if (w<16)
+    {
+        for (y=0; y<h; y+=2)
+        {
+            for (x=0; x<w; x+=2)
+            {
+                /* Output two 2x1 macroblocks to form a 2x2 block from input */
+                uint8_t u_val = *u_p++;
+                uint8_t v_val = *v_p++;
+
+                /* Even row, first pixel */
+                *dest_even++ = u_val;
+                *dest_even++ = *y_p_even++;
+
+                /* Even row, second pixel */
+                *dest_even++ = v_val;
+                *dest_even++ = *y_p_even++;
+
+                /* Odd row, first pixel */
+                *dest_odd++ = u_val;
+                *dest_odd++ = *y_p_odd++;
+
+                /* Odd row, second pixel */
+                *dest_odd++ = v_val;
+                *dest_odd++ = *y_p_odd++;
+            }
+
+            dest_even += w * 2;
+            dest_odd += w * 2;
+
+            u_p += ((uv_pitch << 1) - w) >> 1;
+            v_p += ((uv_pitch << 1) - w) >> 1;
+
+            y_p_even += (y_pitch - w) + y_pitch;
+            y_p_odd += (y_pitch - w) + y_pitch;
+        }
+    }
+    else
+    {
+        for (y=0; y<h; y+=2)
+        {
+            x=w;
+            do {
+                // avoid using d8-d15 (q4-q7) aapcs callee-save registers
+                asm volatile (
+                        "1:\n\t"
+                        "vld1.u8   {d0}, [%[u_p]]!\n\t"
+                        "sub       %[x],%[x],#16\n\t"
+                        "cmp       %[x],#16\n\t"
+                        "vld1.u8   {d1}, [%[v_p]]!\n\t"
+                        "vld1.u8   {q1}, [%[y_p_even]]!\n\t"
+                        "vzip.u8   d0, d1\n\t"
+                        "vld1.u8   {q2}, [%[y_p_odd]]!\n\t"
+                // use 2-element struct stores to zip up y with y&v
+                        "vst2.u8   {q0,q1}, [%[dest_even]]!\n\t"
+                        "vmov.u8   q1, q2\n\t"
+                        "vst2.u8   {q0,q1}, [%[dest_odd]]!\n\t"
+                        "bhs       1b\n\t"
+                        : [u_p] "+r" (u_p), [v_p] "+r" (v_p), [y_p_even] "+r" (y_p_even), [y_p_odd] "+r" (y_p_odd),
+                          [dest_even] "+r" (dest_even), [dest_odd] "+r" (dest_odd),
+                          [x] "+r" (x)
+                        :
+                        : "cc", "memory", "d0","d1","d2","d3","d4","d5"
+                        );
+                if (x!=0)
+                {
+                    // overlap final 16-pixel block to process requested width exactly
+                    x = 16-x;
+                    u_p -= x/2;
+                    v_p -= x/2;
+                    y_p_even -= x;
+                    y_p_odd -= x;
+                    dest_even -= x*2;
+                    dest_odd -= x*2;
+                    x = 16;
+                    // do another 16-pixel block
+                }
+            }
+            while (x!=0);
+
+            dest_even += w * 2;
+            dest_odd += w * 2;
+
+            u_p += ((uv_pitch << 1) - w) >> 1;
+            v_p += ((uv_pitch << 1) - w) >> 1;
+
+            y_p_even += (y_pitch - w) + y_pitch;
+            y_p_odd += (y_pitch - w) + y_pitch;
+        }
+    }
+}
+
