ARM Skia NEON patches - 16/17 - Blitmask

src/opts/SkColor_opts_neon.h

 #ifndef SkColor_opts_neon_DEFINED
 #define SkColor_opts_neon_DEFINED
 
 #include "SkTypes.h"
+#include "SkColorPriv.h"
 
 #include <arm_neon.h>
 
 #define NEON_A (SK_A32_SHIFT / 8)
 #define NEON_R (SK_R32_SHIFT / 8)
 #define NEON_G (SK_G32_SHIFT / 8)
 #define NEON_B (SK_B32_SHIFT / 8)
 
 static inline uint16x8_t SkAlpha255To256_neon8(uint8x8_t alpha) {
     return vaddw_u8(vdupq_n_u16(1), alpha);
@@ skipping 43 matching lines @@
 
     uint16x8_t ret;
 
     ret = vshll_n_u8(vsrc.val[NEON_R], 8);
     ret = vsriq_n_u16(ret, vshll_n_u8(vsrc.val[NEON_G], 8), SK_R16_BITS);
     ret = vsriq_n_u16(ret, vshll_n_u8(vsrc.val[NEON_B], 8), SK_R16_BITS + SK_G16_BITS);
 
     return ret;
 }
 
+/* This function blends 8 pixels of the same channel in the exact same way as
+ * SkBlend32.
+ */
+static inline uint8x8_t SkBlend32_neon8(uint8x8_t src, uint8x8_t dst, uint16x8_t scale) {
+    int16x8_t src_wide, dst_wide;
+
+    src_wide = vreinterpretq_s16_u16(vmovl_u8(src));
+    dst_wide = vreinterpretq_s16_u16(vmovl_u8(dst));
+
+    src_wide = (src_wide - dst_wide) * vreinterpretq_s16_u16(scale);
+
+    dst_wide += vshrq_n_s16(src_wide, 5);
+
+    return vmovn_u16(vreinterpretq_u16_s16(dst_wide));
+}
+
 #endif /* #ifndef SkColor_opts_neon_DEFINED */