void imageFilterMean_SSE2(unsigned char *src1, unsigned char *src2, unsigned char *dst, int length)
{
int n = length;
// Compute first few values so we're on a 16-byte boundary in dst
while( (((long)dst & 0xF) > 0) && (n > 0) ) {
MEAN_PIXEL();
--n; ++dst; ++src1; ++src2;
}
// Do bulk of processing using SSE2 (find the mean of 16 8-bit unsigned integers, with saturation)
__m128i mask = _mm_set1_epi8(0x7F);
while(n >= 16) {
__m128i s1 = _mm_loadu_si128((__m128i*)src1);
s1 = _mm_srli_epi16(s1, 1); // shift right 1
s1 = _mm_and_si128(s1, mask); // apply byte-mask
__m128i s2 = _mm_loadu_si128((__m128i*)src2);
s2 = _mm_srli_epi16(s2, 1); // shift right 1
s2 = _mm_and_si128(s2, mask); // apply byte-mask
__m128i r = _mm_adds_epu8(s1, s2);
_mm_store_si128((__m128i*)dst, r);
n -= 16; src1 += 16; src2 += 16; dst += 16;
}
// If any bytes are left over, deal with them individually
++n;
BASIC_MEAN();
}
void imageFilterMean_Altivec(unsigned char *src1, unsigned char *src2, unsigned char *dst, int length)
{
int n = length;
// Compute first few values so we're on a 16-byte boundary in dst
while( (((long)dst & 0xF) > 0) && (n > 0) ) {
MEAN_PIXEL();
--n; ++dst; ++src1; ++src2;
}
// Do bulk of processing using Altivec (find the mean of 16 8-bit unsigned integers, with saturation)
vector unsigned char rshft = vec_splat_u8(0x1);
while(n >= 16) {
vector unsigned char s1 = vec_ld(0,src1);
s1 = vec_sr(s1, rshft); // shift right 1
vector unsigned char s2 = vec_ld(0,src2);
s2 = vec_sr(s2, rshft); // shift right 1
vector unsigned char r = vec_adds(s1, s2);
vec_st(r,0,dst);
n -= 16; src1 += 16; src2 += 16; dst += 16;
}
// If any bytes are left over, deal with them individually
++n;
BASIC_MEAN();
}
