cosmetics: NEON scaling code

Change-Id: Ib91054622c1f09c4ca523bc6837d7d8ab9f03618

1 files changed, 85 insertions, 98 deletions

diff --git a/vp9/encoder/arm/neon/vp9_frame_scale_neon.c b/vp9/encoder/arm/neon/vp9_frame_scale_neon.c
index bbed00f58..ce19e6cd1 100644
--- a/vp9/encoder/arm/neon/vp9_frame_scale_neon.c
+++ b/vp9/encoder/arm/neon/vp9_frame_scale_neon.c
@@ -170,37 +170,18 @@ static INLINE void scale_plane_4_to_1_bilinear_phase_non_0_neon(
   } while (--y);
 }
 
-static INLINE uint8x8_t scale_filter(const uint8x8_t *const s,
-                                     const int16x8_t filters) {
-  const int16x8_t filter3 = vdupq_lane_s16(vget_low_s16(filters), 3);
-  const int16x8_t filter4 = vdupq_lane_s16(vget_high_s16(filters), 0);
-  int16x8_t ss[8];
-
-  ss[0] = vreinterpretq_s16_u16(vmovl_u8(s[0]));
-  ss[1] = vreinterpretq_s16_u16(vmovl_u8(s[1]));
-  ss[2] = vreinterpretq_s16_u16(vmovl_u8(s[2]));
-  ss[3] = vreinterpretq_s16_u16(vmovl_u8(s[3]));
-  ss[4] = vreinterpretq_s16_u16(vmovl_u8(s[4]));
-  ss[5] = vreinterpretq_s16_u16(vmovl_u8(s[5]));
-  ss[6] = vreinterpretq_s16_u16(vmovl_u8(s[6]));
-  ss[7] = vreinterpretq_s16_u16(vmovl_u8(s[7]));
-
-  return convolve8_8(ss[0], ss[1], ss[2], ss[3], ss[4], ss[5], ss[6], ss[7],
-                     filters, filter3, filter4);
-}
-
 static void scale_plane_2_to_1_general_neon(const uint8_t *src,
                                             const int src_stride, uint8_t *dst,
                                             const int dst_stride, const int w,
                                             const int h,
                                             const int16_t *const coef,
                                             uint8_t *const temp_buffer) {
-  const int max_width_hor = (w + 3) & ~3;
-  const int max_width_ver = (w + 7) & ~7;
-  const int max_height_hor = (2 * h + SUBPEL_TAPS - 2 + 7) & ~7;
-  const int max_height_ver = (h + 3) & ~3;
+  const int width_hor = (w + 3) & ~3;
+  const int width_ver = (w + 7) & ~7;
+  const int height_hor = (2 * h + SUBPEL_TAPS - 2 + 7) & ~7;
+  const int height_ver = (h + 3) & ~3;
   const int16x8_t filters = vld1q_s16(coef);
-  int x, y = max_height_hor;
+  int x, y = height_hor;
   uint8_t *t = temp_buffer;
   uint8x8_t s[14], d[4];
 
@@ -208,14 +189,14 @@ static void scale_plane_2_to_1_general_neon(const uint8_t *src,
 
   src -= (SUBPEL_TAPS / 2 - 1) * src_stride + SUBPEL_TAPS / 2 + 1;
 
-  // horizontal
+  // horizontal 4x8
   // Note: processing 4x8 is about 20% faster than processing row by row using
   // vld4_u8().
   do {
     load_u8_8x8(src + 2, src_stride, &s[0], &s[1], &s[2], &s[3], &s[4], &s[5],
                 &s[6], &s[7]);
     transpose_u8_8x8(&s[0], &s[1], &s[2], &s[3], &s[4], &s[5], &s[6], &s[7]);
-    x = max_width_hor;
+    x = width_hor;
 
     do {
       src += 8;
@@ -224,31 +205,31 @@ static void scale_plane_2_to_1_general_neon(const uint8_t *src,
       transpose_u8_8x8(&s[6], &s[7], &s[8], &s[9], &s[10], &s[11], &s[12],
                        &s[13]);
 
-      d[0] = scale_filter(&s[0], filters);  // 00 10 20 30 40 50 60 70
-      d[1] = scale_filter(&s[2], filters);  // 01 11 21 31 41 51 61 71
-      d[2] = scale_filter(&s[4], filters);  // 02 12 22 32 42 52 62 72
-      d[3] = scale_filter(&s[6], filters);  // 03 13 23 33 43 53 63 73
+      d[0] = scale_filter_8(&s[0], filters);  // 00 10 20 30 40 50 60 70
+      d[1] = scale_filter_8(&s[2], filters);  // 01 11 21 31 41 51 61 71
+      d[2] = scale_filter_8(&s[4], filters);  // 02 12 22 32 42 52 62 72
+      d[3] = scale_filter_8(&s[6], filters);  // 03 13 23 33 43 53 63 73
       // 00 01 02 03 40 41 42 43
       // 10 11 12 13 50 51 52 53
       // 20 21 22 23 60 61 62 63
       // 30 31 32 33 70 71 72 73
       transpose_u8_8x4(&d[0], &d[1], &d[2], &d[3]);
-      vst1_lane_u32((uint32_t *)(t + 0 * max_width_hor),
-                    vreinterpret_u32_u8(d[0]), 0);
-      vst1_lane_u32((uint32_t *)(t + 1 * max_width_hor),
-                    vreinterpret_u32_u8(d[1]), 0);
-      vst1_lane_u32((uint32_t *)(t + 2 * max_width_hor),
-                    vreinterpret_u32_u8(d[2]), 0);
-      vst1_lane_u32((uint32_t *)(t + 3 * max_width_hor),
-                    vreinterpret_u32_u8(d[3]), 0);
-      vst1_lane_u32((uint32_t *)(t + 4 * max_width_hor),
-                    vreinterpret_u32_u8(d[0]), 1);
-      vst1_lane_u32((uint32_t *)(t + 5 * max_width_hor),
-                    vreinterpret_u32_u8(d[1]), 1);
-      vst1_lane_u32((uint32_t *)(t + 6 * max_width_hor),
-                    vreinterpret_u32_u8(d[2]), 1);
-      vst1_lane_u32((uint32_t *)(t + 7 * max_width_hor),
-                    vreinterpret_u32_u8(d[3]), 1);
+      vst1_lane_u32((uint32_t *)(t + 0 * width_hor), vreinterpret_u32_u8(d[0]),
+                    0);
+      vst1_lane_u32((uint32_t *)(t + 1 * width_hor), vreinterpret_u32_u8(d[1]),
+                    0);
+      vst1_lane_u32((uint32_t *)(t + 2 * width_hor), vreinterpret_u32_u8(d[2]),
+                    0);
+      vst1_lane_u32((uint32_t *)(t + 3 * width_hor), vreinterpret_u32_u8(d[3]),
+                    0);
+      vst1_lane_u32((uint32_t *)(t + 4 * width_hor), vreinterpret_u32_u8(d[0]),
+                    1);
+      vst1_lane_u32((uint32_t *)(t + 5 * width_hor), vreinterpret_u32_u8(d[1]),
+                    1);
+      vst1_lane_u32((uint32_t *)(t + 6 * width_hor), vreinterpret_u32_u8(d[2]),
+                    1);
+      vst1_lane_u32((uint32_t *)(t + 7 * width_hor), vreinterpret_u32_u8(d[3]),
+                    1);
 
       s[0] = s[8];
       s[1] = s[9];
@@ -260,29 +241,29 @@ static void scale_plane_2_to_1_general_neon(const uint8_t *src,
       t += 4;
       x -= 4;
     } while (x);
-    src += 8 * src_stride - 2 * max_width_hor;
-    t += 7 * max_width_hor;
+    src += 8 * src_stride - 2 * width_hor;
+    t += 7 * width_hor;
     y -= 8;
   } while (y);
 
-  // vertical
-  x = max_width_ver;
+  // vertical 8x4
+  x = width_ver;
   t = temp_buffer;
   do {
-    load_u8_8x8(t, max_width_hor, &s[0], &s[1], &s[2], &s[3], &s[4], &s[5],
-                &s[6], &s[7]);
-    t += 6 * max_width_hor;
-    y = max_height_ver;
+    load_u8_8x8(t, width_hor, &s[0], &s[1], &s[2], &s[3], &s[4], &s[5], &s[6],
+                &s[7]);
+    t += 6 * width_hor;
+    y = height_ver;
 
     do {
-      load_u8_8x8(t, max_width_hor, &s[6], &s[7], &s[8], &s[9], &s[10], &s[11],
+      load_u8_8x8(t, width_hor, &s[6], &s[7], &s[8], &s[9], &s[10], &s[11],
                   &s[12], &s[13]);
-      t += 8 * max_width_hor;
+      t += 8 * width_hor;
 
-      d[0] = scale_filter(&s[0], filters);
-      d[1] = scale_filter(&s[2], filters);
-      d[2] = scale_filter(&s[4], filters);
-      d[3] = scale_filter(&s[6], filters);
+      d[0] = scale_filter_8(&s[0], filters);
+      d[1] = scale_filter_8(&s[2], filters);
+      d[2] = scale_filter_8(&s[4], filters);
+      d[3] = scale_filter_8(&s[6], filters);
       vst1_u8(dst + 0 * dst_stride, d[0]);
       vst1_u8(dst + 1 * dst_stride, d[1]);
       vst1_u8(dst + 2 * dst_stride, d[2]);
@@ -298,9 +279,9 @@ static void scale_plane_2_to_1_general_neon(const uint8_t *src,
       dst += 4 * dst_stride;
       y -= 4;
     } while (y);
-    t -= max_width_hor * (2 * max_height_ver + 6);
+    t -= width_hor * (2 * height_ver + 6);
     t += 8;
-    dst -= max_height_ver * dst_stride;
+    dst -= height_ver * dst_stride;
     dst += 8;
     x -= 8;
   } while (x);
@@ -312,12 +293,12 @@ static void scale_plane_4_to_1_general_neon(const uint8_t *src,
                                             const int h,
                                             const int16_t *const coef,
                                             uint8_t *const temp_buffer) {
-  const int max_width_hor = (w + 1) & ~1;
-  const int max_width_ver = (w + 7) & ~7;
-  const int max_height_hor = (4 * h + SUBPEL_TAPS - 2 + 7) & ~7;
-  const int max_height_ver = (h + 1) & ~1;
+  const int width_hor = (w + 1) & ~1;
+  const int width_ver = (w + 7) & ~7;
+  const int height_hor = (4 * h + SUBPEL_TAPS - 2 + 7) & ~7;
+  const int height_ver = (h + 1) & ~1;
   const int16x8_t filters = vld1q_s16(coef);
-  int x, y = max_height_hor;
+  int x, y = height_hor;
   uint8_t *t = temp_buffer;
   uint8x8_t s[12], d[2];
 
@@ -325,14 +306,14 @@ static void scale_plane_4_to_1_general_neon(const uint8_t *src,
 
   src -= (SUBPEL_TAPS / 2 - 1) * src_stride + SUBPEL_TAPS / 2 + 3;
 
-  // horizontal
+  // horizontal 2x8
   // Note: processing 2x8 is about 20% faster than processing row by row using
   // vld4_u8().
   do {
     load_u8_8x8(src + 4, src_stride, &s[0], &s[1], &s[2], &s[3], &s[4], &s[5],
                 &s[6], &s[7]);
     transpose_u8_4x8(&s[0], &s[1], &s[2], &s[3], s[4], s[5], s[6], s[7]);
-    x = max_width_hor;
+    x = width_hor;
 
     do {
       uint8x8x2_t dd;
@@ -342,26 +323,26 @@ static void scale_plane_4_to_1_general_neon(const uint8_t *src,
       transpose_u8_8x8(&s[4], &s[5], &s[6], &s[7], &s[8], &s[9], &s[10],
                        &s[11]);
 
-      d[0] = scale_filter(&s[0], filters);  // 00 10 20 30 40 50 60 70
-      d[1] = scale_filter(&s[4], filters);  // 01 11 21 31 41 51 61 71
+      d[0] = scale_filter_8(&s[0], filters);  // 00 10 20 30 40 50 60 70
+      d[1] = scale_filter_8(&s[4], filters);  // 01 11 21 31 41 51 61 71
       // dd.val[0]: 00 01 20 21 40 41 60 61
       // dd.val[1]: 10 11 30 31 50 51 70 71
       dd = vtrn_u8(d[0], d[1]);
-      vst1_lane_u16((uint16_t *)(t + 0 * max_width_hor),
+      vst1_lane_u16((uint16_t *)(t + 0 * width_hor),
                     vreinterpret_u16_u8(dd.val[0]), 0);
-      vst1_lane_u16((uint16_t *)(t + 1 * max_width_hor),
+      vst1_lane_u16((uint16_t *)(t + 1 * width_hor),
                     vreinterpret_u16_u8(dd.val[1]), 0);
-      vst1_lane_u16((uint16_t *)(t + 2 * max_width_hor),
+      vst1_lane_u16((uint16_t *)(t + 2 * width_hor),
                     vreinterpret_u16_u8(dd.val[0]), 1);
-      vst1_lane_u16((uint16_t *)(t + 3 * max_width_hor),
+      vst1_lane_u16((uint16_t *)(t + 3 * width_hor),
                     vreinterpret_u16_u8(dd.val[1]), 1);
-      vst1_lane_u16((uint16_t *)(t + 4 * max_width_hor),
+      vst1_lane_u16((uint16_t *)(t + 4 * width_hor),
                     vreinterpret_u16_u8(dd.val[0]), 2);
-      vst1_lane_u16((uint16_t *)(t + 5 * max_width_hor),
+      vst1_lane_u16((uint16_t *)(t + 5 * width_hor),
                     vreinterpret_u16_u8(dd.val[1]), 2);
-      vst1_lane_u16((uint16_t *)(t + 6 * max_width_hor),
+      vst1_lane_u16((uint16_t *)(t + 6 * width_hor),
                     vreinterpret_u16_u8(dd.val[0]), 3);
-      vst1_lane_u16((uint16_t *)(t + 7 * max_width_hor),
+      vst1_lane_u16((uint16_t *)(t + 7 * width_hor),
                     vreinterpret_u16_u8(dd.val[1]), 3);
 
       s[0] = s[8];
@@ -372,26 +353,26 @@ static void scale_plane_4_to_1_general_neon(const uint8_t *src,
       t += 2;
       x -= 2;
     } while (x);
-    src += 8 * src_stride - 4 * max_width_hor;
-    t += 7 * max_width_hor;
+    src += 8 * src_stride - 4 * width_hor;
+    t += 7 * width_hor;
     y -= 8;
   } while (y);
 
-  // vertical
-  x = max_width_ver;
+  // vertical 8x2
+  x = width_ver;
   t = temp_buffer;
   do {
-    load_u8_8x4(t, max_width_hor, &s[0], &s[1], &s[2], &s[3]);
-    t += 4 * max_width_hor;
-    y = max_height_ver;
+    load_u8_8x4(t, width_hor, &s[0], &s[1], &s[2], &s[3]);
+    t += 4 * width_hor;
+    y = height_ver;
 
     do {
-      load_u8_8x8(t, max_width_hor, &s[4], &s[5], &s[6], &s[7], &s[8], &s[9],
+      load_u8_8x8(t, width_hor, &s[4], &s[5], &s[6], &s[7], &s[8], &s[9],
                   &s[10], &s[11]);
-      t += 8 * max_width_hor;
+      t += 8 * width_hor;
 
-      d[0] = scale_filter(&s[0], filters);
-      d[1] = scale_filter(&s[4], filters);
+      d[0] = scale_filter_8(&s[0], filters);
+      d[1] = scale_filter_8(&s[4], filters);
       vst1_u8(dst + 0 * dst_stride, d[0]);
       vst1_u8(dst + 1 * dst_stride, d[1]);
 
@@ -403,9 +384,9 @@ static void scale_plane_4_to_1_general_neon(const uint8_t *src,
       dst += 2 * dst_stride;
       y -= 2;
     } while (y);
-    t -= max_width_hor * (4 * max_height_ver + 4);
+    t -= width_hor * (4 * height_ver + 4);
     t += 8;
-    dst -= max_height_ver * dst_stride;
+    dst -= height_ver * dst_stride;
     dst += 8;
     x -= 8;
   } while (x);
@@ -423,7 +404,11 @@ void vp9_scale_and_extend_frame_neon(const YV12_BUFFER_CONFIG *src,
   const int dst_uv_h = dst_h / 2;
   int scaled = 0;
 
+  // phase_scaler is usually 0 or 8.
+  assert(phase_scaler >= 0 && phase_scaler < 16);
+
   if (2 * dst_w == src_w && 2 * dst_h == src_h) {
+    // 2 to 1
     scaled = 1;
     if (phase_scaler == 0) {
       scale_plane_2_to_1_phase_0_neon(src->y_buffer, src->y_stride,
@@ -448,10 +433,10 @@ void vp9_scale_and_extend_frame_neon(const YV12_BUFFER_CONFIG *src,
           src->v_buffer, src->uv_stride, dst->v_buffer, dst->uv_stride,
           dst_uv_w, dst_uv_h, c0, c1);
     } else {
-      const int buffer_max_width = (dst_w + 3) & ~3;
-      const int buffer_max_height = (2 * dst_h + SUBPEL_TAPS - 2 + 7) & ~7;
+      const int buffer_stride = (dst_w + 3) & ~3;
+      const int buffer_height = (2 * dst_h + SUBPEL_TAPS - 2 + 7) & ~7;
       uint8_t *const temp_buffer =
-          (uint8_t *)malloc(buffer_max_width * buffer_max_height);
+          (uint8_t *)malloc(buffer_stride * buffer_height);
       if (temp_buffer) {
         scale_plane_2_to_1_general_neon(
             src->y_buffer, src->y_stride, dst->y_buffer, dst->y_stride, dst_w,
@@ -470,6 +455,7 @@ void vp9_scale_and_extend_frame_neon(const YV12_BUFFER_CONFIG *src,
       }
     }
   } else if (4 * dst_w == src_w && 4 * dst_h == src_h) {
+    // 4 to 1
     scaled = 1;
     if (phase_scaler == 0) {
       scale_plane_4_to_1_phase_0_neon(src->y_buffer, src->y_stride,
@@ -494,10 +480,10 @@ void vp9_scale_and_extend_frame_neon(const YV12_BUFFER_CONFIG *src,
           src->v_buffer, src->uv_stride, dst->v_buffer, dst->uv_stride,
           dst_uv_w, dst_uv_h, c0, c1);
     } else {
-      const int buffer_max_width = (dst_w + 1) & ~1;
-      const int buffer_max_height = (4 * dst_h + SUBPEL_TAPS - 2 + 7) & ~7;
+      const int buffer_stride = (dst_w + 1) & ~1;
+      const int buffer_height = (4 * dst_h + SUBPEL_TAPS - 2 + 7) & ~7;
       uint8_t *const temp_buffer =
-          (uint8_t *)malloc(buffer_max_width * buffer_max_height);
+          (uint8_t *)malloc(buffer_stride * buffer_height);
       if (temp_buffer) {
         scale_plane_4_to_1_general_neon(
             src->y_buffer, src->y_stride, dst->y_buffer, dst->y_stride, dst_w,
@@ -520,6 +506,7 @@ void vp9_scale_and_extend_frame_neon(const YV12_BUFFER_CONFIG *src,
   if (scaled) {
     vpx_extend_frame_borders(dst);
   } else {
+    // Call c version for all other scaling ratios.
     vp9_scale_and_extend_frame_c(src, dst, filter_type, phase_scaler);
   }
 }