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dec_neon: DC4: use pair-wise adds for top row

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reduces load count, slightly faster

Change-Id: I880340ef8ef75ce4ce321c330f56f86b758bda08
This commit is contained in:
James Zern 2014-10-23 15:01:50 +02:00
parent f7ada560ce
commit b5bc15305b
1 changed files with 6 additions and 10 deletions
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16
src/dsp/dec_neon.c
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@ -1262,21 +1262,17 @@ static void TransformAC3(const int16_t* in, uint8_t* dst) {
// 4x4
static void DC4(uint8_t* dst) { // DC
const uint16x8_t A0 = vmovl_u8(vld1_u8(dst - BPS + 0));
const uint16x8_t A1 = vmovl_u8(vld1_u8(dst - BPS + 1));
const uint16x8_t A2 = vmovl_u8(vld1_u8(dst - BPS + 2));
const uint16x8_t A3 = vmovl_u8(vld1_u8(dst - BPS + 3));
const uint8x8_t A = vld1_u8(dst - BPS); // top row
const uint16x4_t p0 = vpaddl_u8(A); // cascading summation of the top
const uint16x4_t p1 = vpadd_u16(p0, p0);
const uint16x8_t L0 = vmovl_u8(vld1_u8(dst + 0 * BPS - 1));
const uint16x8_t L1 = vmovl_u8(vld1_u8(dst + 1 * BPS - 1));
const uint16x8_t L2 = vmovl_u8(vld1_u8(dst + 2 * BPS - 1));
const uint16x8_t L3 = vmovl_u8(vld1_u8(dst + 3 * BPS - 1));
const uint16x8_t s0 = vaddq_u16(A0, L0);
const uint16x8_t s1 = vaddq_u16(A1, L1);
const uint16x8_t s2 = vaddq_u16(A2, L2);
const uint16x8_t s3 = vaddq_u16(A3, L3);
const uint16x8_t s0 = vaddq_u16(L0, L1);
const uint16x8_t s1 = vaddq_u16(L2, L3);
const uint16x8_t s01 = vaddq_u16(s0, s1);
const uint16x8_t s23 = vaddq_u16(s2, s3);
const uint16x8_t sum = vaddq_u16(s01, s23);
const uint16x8_t sum = vaddq_u16(s01, vcombine_u16(p1, p1));
const uint8x8_t dc0 = vrshrn_n_u16(sum, 3); // (sum + 4) >> 3
const uint8x8_t dc = vdup_lane_u8(dc0, 0);
int i;