[VSX] Optimize PROCESS16 macro

The PROCESS16 macro now uses 8-bit lanes instead of 16-bit lanes.

SADTest Speed Test (POWER8 Model 2.1)
16x8  Old VSX time = 16.7 ms, new VSX time = 9.1 ms [1.8x]
16x16 Old VSX time = 15.7 ms, new VSX time = 7.9 ms [2.0x]
16x32 Old VSX time = 14.4 ms, new VSX time = 7.2 ms [2.0x]
32x16 Old VSX time = 14.0 ms, new VSX time = 7.4 ms [1.9x]
32x32 Old VSX time = 13.4 ms, new VSX time = 6.5 ms [2.0x]
32x64 Old VSX time = 12.7 ms, new VSX time = 6.3 ms [2.0x]
64x32 Old VSX time = 12.6 ms, new VSX time = 6.3 ms [2.0x]
64x64 Old VSX time = 12.7 ms, new VSX time = 6.2 ms [2.0x]

Change-Id: I51776f0e428162e78edde8eac47f30ffd2379873

diff --git a/vpx_dsp/ppc/sad_vsx.c b/vpx_dsp/ppc/sad_vsx.c
index b41c05b48d1a08ad7da75bfb17853f33f5f86d29..18673f68215ee50eb54fcbc16b1053ba4b4c7507 100644 (file)
--- a/vpx_dsp/ppc/sad_vsx.c
+++ b/vpx_dsp/ppc/sad_vsx.c
@@ -17,19 +17,11 @@
 #include "vpx/vpx_integer.h"
 #include "vpx_ports/mem.h"
 
-#define PROCESS16(offset)           \
-  v_a = vec_vsx_ld(offset, a);      \
-  v_b = vec_vsx_ld(offset, b);      \
-  v_ah = unpack_to_s16_h(v_a);      \
-  v_al = unpack_to_s16_l(v_a);      \
-  v_bh = unpack_to_s16_h(v_b);      \
-  v_bl = unpack_to_s16_l(v_b);      \
-  v_subh = vec_sub(v_ah, v_bh);     \
-  v_subl = vec_sub(v_al, v_bl);     \
-  v_absh = vec_abs(v_subh);         \
-  v_absl = vec_abs(v_subl);         \
-  v_sad = vec_sum4s(v_absh, v_sad); \
-  v_sad = vec_sum4s(v_absl, v_sad);
+#define PROCESS16(offset)                                \
+  v_a = vec_vsx_ld(offset, a);                           \
+  v_b = vec_vsx_ld(offset, b);                           \
+  v_abs = vec_sub(vec_max(v_a, v_b), vec_min(v_a, v_b)); \
+  v_sad = vec_sum4s(v_abs, v_sad);
 
 #define SAD8(height)                                                     \
   unsigned int vpx_sad8x##height##_vsx(const uint8_t *a, int a_stride,   \
@@ -39,11 +31,7 @@
     uint32x4_t v_sad = vec_zeros_u32;                                    \
                                                                          \
     do {                                                                 \
-      v_a = vec_vsx_ld(0, a);                                            \
-      v_b = vec_vsx_ld(0, b);                                            \
-                                                                         \
-      v_abs = vec_sub(vec_max(v_a, v_b), vec_min(v_a, v_b));             \
-      v_sad = vec_sum4s(v_abs, v_sad);                                   \
+      PROCESS16(0)                                                       \
                                                                          \
       a += a_stride;                                                     \
       b += b_stride;                                                     \
@@ -56,54 +44,48 @@
 #define SAD16(height)                                                     \
   unsigned int vpx_sad16x##height##_vsx(const uint8_t *a, int a_stride,   \
                                         const uint8_t *b, int b_stride) { \
-    int y;                                                                \
-    unsigned int sad[4];                                                  \
-    uint8x16_t v_a, v_b;                                                  \
-    int16x8_t v_ah, v_al, v_bh, v_bl, v_absh, v_absl, v_subh, v_subl;     \
-    int32x4_t v_sad = vec_splat_s32(0);                                   \
+    int y = 0;                                                            \
+    uint8x16_t v_a, v_b, v_abs;                                           \
+    uint32x4_t v_sad = vec_zeros_u32;                                     \
                                                                           \
-    for (y = 0; y < height; y++) {                                        \
+    do {                                                                  \
       PROCESS16(0);                                                       \
                                                                           \
       a += a_stride;                                                      \
       b += b_stride;                                                      \
-    }                                                                     \
-    vec_vsx_st((uint32x4_t)v_sad, 0, sad);                                \
+      y++;                                                                \
+    } while (y < height);                                                 \
                                                                           \
-    return sad[3] + sad[2] + sad[1] + sad[0];                             \
+    return v_sad[3] + v_sad[2] + v_sad[1] + v_sad[0];                     \
   }
 
 #define SAD32(height)                                                     \
   unsigned int vpx_sad32x##height##_vsx(const uint8_t *a, int a_stride,   \
                                         const uint8_t *b, int b_stride) { \
-    int y;                                                                \
-    unsigned int sad[4];                                                  \
-    uint8x16_t v_a, v_b;                                                  \
-    int16x8_t v_ah, v_al, v_bh, v_bl, v_absh, v_absl, v_subh, v_subl;     \
-    int32x4_t v_sad = vec_splat_s32(0);                                   \
+    int y = 0;                                                            \
+    uint8x16_t v_a, v_b, v_abs;                                           \
+    uint32x4_t v_sad = vec_zeros_u32;                                     \
                                                                           \
-    for (y = 0; y < height; y++) {                                        \
+    do {                                                                  \
       PROCESS16(0);                                                       \
       PROCESS16(16);                                                      \
                                                                           \
       a += a_stride;                                                      \
       b += b_stride;                                                      \
-    }                                                                     \
-    vec_vsx_st((uint32x4_t)v_sad, 0, sad);                                \
+      y++;                                                                \
+    } while (y < height);                                                 \
                                                                           \
-    return sad[3] + sad[2] + sad[1] + sad[0];                             \
+    return v_sad[3] + v_sad[2] + v_sad[1] + v_sad[0];                     \
   }
 
 #define SAD64(height)                                                     \
   unsigned int vpx_sad64x##height##_vsx(const uint8_t *a, int a_stride,   \
                                         const uint8_t *b, int b_stride) { \
-    int y;                                                                \
-    unsigned int sad[4];                                                  \
-    uint8x16_t v_a, v_b;                                                  \
-    int16x8_t v_ah, v_al, v_bh, v_bl, v_absh, v_absl, v_subh, v_subl;     \
-    int32x4_t v_sad = vec_splat_s32(0);                                   \
+    int y = 0;                                                            \
+    uint8x16_t v_a, v_b, v_abs;                                           \
+    uint32x4_t v_sad = vec_zeros_u32;                                     \
                                                                           \
-    for (y = 0; y < height; y++) {                                        \
+    do {                                                                  \
       PROCESS16(0);                                                       \
       PROCESS16(16);                                                      \
       PROCESS16(32);                                                      \
@@ -111,10 +93,10 @@
                                                                           \
       a += a_stride;                                                      \
       b += b_stride;                                                      \
-    }                                                                     \
-    vec_vsx_st((uint32x4_t)v_sad, 0, sad);                                \
+      y++;                                                                \
+    } while (y < height);                                                 \
                                                                           \
-    return sad[3] + sad[2] + sad[1] + sad[0];                             \
+    return v_sad[3] + v_sad[2] + v_sad[1] + v_sad[0];                     \
   }
 
 SAD8(4);