alpha_processing_neon.c: fix Dispatch/ExtractAlpha_NEON
the trailing width % 8 bytes would clear the upper bytes of
alpha_mask as they're done one at a time
since:
NEON: implement several alpha-processing functions
@@ -83,7 +83,7 @@ static void ApplyAlphaMultiply_NEON(uint8_t* rgba, int alpha_first,
static int DispatchAlpha_NEON(const uint8_t* WEBP_RESTRICT alpha,
int alpha_stride, int width, int height,
uint8_t* WEBP_RESTRICT dst, int dst_stride) {
- uint32_t alpha_mask = 0xffffffffu;
+ uint32_t alpha_mask = 0xffu;
uint8x8_t mask8 = vdup_n_u8(0xff);
uint32_t tmp[2];
int i, j;
@@ -107,6 +107,7 @@ static int DispatchAlpha_NEON(const uint8_t* WEBP_RESTRICT alpha,
dst += dst_stride;
}
vst1_u8((uint8_t*)tmp, mask8);
+ alpha_mask *= 0x01010101;
alpha_mask &= tmp[0];
alpha_mask &= tmp[1];
return (alpha_mask != 0xffffffffu);
@@ -135,7 +136,7 @@ static void DispatchAlphaToGreen_NEON(const uint8_t* WEBP_RESTRICT alpha,
static int ExtractAlpha_NEON(const uint8_t* WEBP_RESTRICT argb, int argb_stride,
int width, int height,
uint8_t* WEBP_RESTRICT alpha, int alpha_stride) {
- uint32_t alpha_mask = 0xffffffffu;
+ uint32_t alpha_mask = 0xffu;
uint8x8_t mask8 = vdup_n_u8(0xff);
uint32_t tmp[2];
int i, j;
@@ -157,6 +158,7 @@ static int ExtractAlpha_NEON(const uint8_t* WEBP_RESTRICT argb, int argb_stride,
alpha += alpha_stride;
}
vst1_u8((uint8_t*)tmp, mask8);
+ alpha_mask *= 0x0101010101;
alpha_mask &= tmp[0];
alpha_mask &= tmp[1];
return (alpha_mask == 0xffffffffu);
