ARM Skia NEON patches - 11 - Blitter_RGB16

src/core/SkBlitter_RGB16.cpp

Index: src/core/SkBlitter_RGB16.cpp
diff --git a/src/core/SkBlitter_RGB16.cpp b/src/core/SkBlitter_RGB16.cpp
index 615a6a39dbe80fc7d5fefdc75e514a75b15fa296..86f0eb61576a89e8a0cc4bc4f2184865834f8fc2 100644
--- a/src/core/SkBlitter_RGB16.cpp
+++ b/src/core/SkBlitter_RGB16.cpp
@@ -390,63 +390,53 @@ void SkRGB16_Opaque_Blitter::blitMask(const SkMask& mask,
     do {
         int w = width;
         if (w >= UNROLL) {
-            uint32x4_t color;        /* can use same one */
-            uint32x4_t dev_lo, dev_hi;
-            uint32x4_t t1;
-            uint32x4_t wn1, wn2;
-            uint16x4_t odev_lo, odev_hi;
-            uint16x4_t alpha_lo, alpha_hi;
-            uint16x8_t  alpha_full;
-
+            uint32x4_t color, dev_lo, dev_hi;
+            uint32x4_t wn1, wn2, tmp;
+            uint32x4_t vmask_g16, vmask_ng16;
+            uint16x8_t valpha, vdev;
+            uint16x4_t odev_lo, odev_hi, valpha_lo, valpha_hi;
+
+            // prepare constants
+            vmask_g16 = vdupq_n_u32(SK_G16_MASK_IN_PLACE);
+            vmask_ng16 = vdupq_n_u32(~SK_G16_MASK_IN_PLACE);
             color = vdupq_n_u32(expanded32);
 
             do {
-                /* alpha is 8x8, widen and split to get pair of 16x4's */
-                alpha_full = vmovl_u8(vld1_u8(alpha));
-                alpha_full = vaddq_u16(alpha_full, vshrq_n_u16(alpha_full,7));
-                alpha_full = vshrq_n_u16(alpha_full, 3);
-                alpha_lo = vget_low_u16(alpha_full);
-                alpha_hi = vget_high_u16(alpha_full);
-
-                dev_lo = vmovl_u16(vld1_u16(device));
-                dev_hi = vmovl_u16(vld1_u16(device+4));
-
-                /* unpack in 32 bits */
-                dev_lo = vorrq_u32(
-                                   vandq_u32(dev_lo, vdupq_n_u32(0x0000F81F)),
-                                   vshlq_n_u32(vandq_u32(dev_lo,
-                                                         vdupq_n_u32(0x000007E0)),
-                                               16)
-                                   );
-                dev_hi = vorrq_u32(
-                                   vandq_u32(dev_hi, vdupq_n_u32(0x0000F81F)),
-                                   vshlq_n_u32(vandq_u32(dev_hi,
-                                                         vdupq_n_u32(0x000007E0)),
-                                               16)
-                                   );
-
-                /* blend the two */
-                t1 = vmulq_u32(vsubq_u32(color, dev_lo), vmovl_u16(alpha_lo));
-                t1 = vshrq_n_u32(t1, 5);
-                dev_lo = vaddq_u32(dev_lo, t1);
-
-                t1 = vmulq_u32(vsubq_u32(color, dev_hi), vmovl_u16(alpha_hi));
-                t1 = vshrq_n_u32(t1, 5);
-                dev_hi = vaddq_u32(dev_hi, t1);
-
-                /* re-compact and store */
-                wn1 = vandq_u32(dev_lo, vdupq_n_u32(0x0000F81F)),
-                wn2 = vshrq_n_u32(dev_lo, 16);
-                wn2 = vandq_u32(wn2, vdupq_n_u32(0x000007E0));
-                odev_lo = vmovn_u32(vorrq_u32(wn1, wn2));
-
-                wn1 = vandq_u32(dev_hi, vdupq_n_u32(0x0000F81F)),
-                wn2 = vshrq_n_u32(dev_hi, 16);
-                wn2 = vandq_u32(wn2, vdupq_n_u32(0x000007E0));
-                odev_hi = vmovn_u32(vorrq_u32(wn1, wn2));
-
-                vst1_u16(device, odev_lo);
-                vst1_u16(device+4, odev_hi);
+                // alpha is 8x8, widen and split to get a pair of 16x4
+                valpha = vaddw_u8(vdupq_n_u16(1), vld1_u8(alpha));
+                valpha = vshrq_n_u16(valpha, 3);
+                valpha_lo = vget_low_u16(valpha);
+                valpha_hi = vget_high_u16(valpha);
+
+                // load pixels
+                vdev = vld1q_u16(device);
+                dev_lo = vmovl_u16(vget_low_u16(vdev));
+                dev_hi = vmovl_u16(vget_high_u16(vdev));
+
+                // unpack them in 32 bits
+                dev_lo = (dev_lo & vmask_ng16) | vshlq_n_u32(dev_lo & vmask_g16, 16);
+                dev_hi = (dev_hi & vmask_ng16) | vshlq_n_u32(dev_hi & vmask_g16, 16);
+
+                // blend with color
+                tmp = (color - dev_lo) * vmovl_u16(valpha_lo);
+                tmp = vshrq_n_u32(tmp, 5);
+                dev_lo += tmp;
+
+                tmp = vmulq_u32(color - dev_hi, vmovl_u16(valpha_hi));
+                tmp = vshrq_n_u32(tmp, 5);
+                dev_hi += tmp;
+
+                // re-compact
+                wn1 = dev_lo & vmask_ng16;
+                wn2 = vshrq_n_u32(dev_lo, 16) & vmask_g16;
+                odev_lo = vmovn_u32(wn1 | wn2);
+
+                wn1 = dev_hi & vmask_ng16;
+                wn2 = vshrq_n_u32(dev_hi, 16) & vmask_g16;
+                odev_hi = vmovn_u32(wn1 | wn2);
+
+                // store
+                vst1q_u16(device, vcombine_u16(odev_lo, odev_hi));
 
                 device += UNROLL;
                 alpha += UNROLL;
@@ -454,7 +444,7 @@ void SkRGB16_Opaque_Blitter::blitMask(const SkMask& mask,
             } while (w >= UNROLL);
         }
 
-        /* residuals (which is everything if we have no neon) */
+        // residuals
         while (w > 0) {
             *device = blend_compact(expanded32, SkExpand_rgb_16(*device),
                                     SkAlpha255To256(*alpha++) >> 3);