| /* | 
 |  * Copyright (c) 2016, Alliance for Open Media. All rights reserved. | 
 |  * | 
 |  * This source code is subject to the terms of the BSD 2 Clause License and | 
 |  * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License | 
 |  * was not distributed with this source code in the LICENSE file, you can | 
 |  * obtain it at www.aomedia.org/license/software. If the Alliance for Open | 
 |  * Media Patent License 1.0 was not distributed with this source code in the | 
 |  * PATENTS file, you can obtain it at www.aomedia.org/license/patent. | 
 |  */ | 
 |  | 
 | #include <tmmintrin.h> | 
 | #include <assert.h> | 
 |  | 
 | #include "config/av1_rtcd.h" | 
 |  | 
 | #include "aom_dsp/aom_dsp_common.h" | 
 | #include "aom_dsp/aom_filter.h" | 
 | #include "aom_dsp/x86/convolve_sse2.h" | 
 | #include "av1/common/convolve.h" | 
 | #include "aom_dsp/x86/convolve_common_intrin.h" | 
 |  | 
 | void av1_highbd_convolve_2d_sr_ssse3( | 
 |     const uint16_t *src, int src_stride, uint16_t *dst, int dst_stride, int w, | 
 |     int h, const InterpFilterParams *filter_params_x, | 
 |     const InterpFilterParams *filter_params_y, const int subpel_x_qn, | 
 |     const int subpel_y_qn, ConvolveParams *conv_params, int bd) { | 
 |   DECLARE_ALIGNED(32, int16_t, im_block[(MAX_SB_SIZE + MAX_FILTER_TAP) * 8]); | 
 |   int im_h = h + filter_params_y->taps - 1; | 
 |   int im_stride = 8; | 
 |   int i, j; | 
 |   const int fo_vert = filter_params_y->taps / 2 - 1; | 
 |   const int fo_horiz = filter_params_x->taps / 2 - 1; | 
 |   const uint16_t *const src_ptr = src - fo_vert * src_stride - fo_horiz; | 
 |  | 
 |   // Check that, even with 12-bit input, the intermediate values will fit | 
 |   // into an unsigned 16-bit intermediate array. | 
 |   assert(bd + FILTER_BITS + 2 - conv_params->round_0 <= 16); | 
 |  | 
 |   const __m128i round_const_x = _mm_set1_epi32( | 
 |       ((1 << conv_params->round_0) >> 1) + (1 << (bd + FILTER_BITS - 1))); | 
 |   const __m128i round_shift_x = _mm_cvtsi32_si128(conv_params->round_0); | 
 |  | 
 |   const __m128i round_const_y = | 
 |       _mm_set1_epi32(((1 << conv_params->round_1) >> 1) - | 
 |                      (1 << (bd + 2 * FILTER_BITS - conv_params->round_0 - 1))); | 
 |   const __m128i round_shift_y = _mm_cvtsi32_si128(conv_params->round_1); | 
 |  | 
 |   const int bits = | 
 |       FILTER_BITS * 2 - conv_params->round_0 - conv_params->round_1; | 
 |   const __m128i round_shift_bits = _mm_cvtsi32_si128(bits); | 
 |   const __m128i round_const_bits = _mm_set1_epi32((1 << bits) >> 1); | 
 |   const __m128i clip_pixel = | 
 |       _mm_set1_epi16(bd == 10 ? 1023 : (bd == 12 ? 4095 : 255)); | 
 |   const __m128i zero = _mm_setzero_si128(); | 
 |  | 
 |   if (filter_params_x->taps == 12) { | 
 |     __m128i coeffs_x[6], coeffs_y[6], s[24]; | 
 |     prepare_coeffs_12tap(filter_params_x, subpel_x_qn, coeffs_x); | 
 |     prepare_coeffs_12tap(filter_params_y, subpel_y_qn, coeffs_y); | 
 |  | 
 |     for (j = 0; j < w; j += 8) { | 
 |       /* Horizontal filter */ | 
 |       { | 
 |         for (i = 0; i < im_h; i += 1) { | 
 |           const __m128i row00 = | 
 |               _mm_loadu_si128((__m128i *)&src_ptr[i * src_stride + j]); | 
 |           const __m128i row01 = | 
 |               _mm_loadu_si128((__m128i *)&src_ptr[i * src_stride + (j + 8)]); | 
 |           const __m128i row02 = | 
 |               _mm_loadu_si128((__m128i *)&src_ptr[i * src_stride + (j + 16)]); | 
 |  | 
 |           // even pixels | 
 |           s[0] = _mm_alignr_epi8(row01, row00, 0); | 
 |           s[1] = _mm_alignr_epi8(row01, row00, 4); | 
 |           s[2] = _mm_alignr_epi8(row01, row00, 8); | 
 |           s[3] = _mm_alignr_epi8(row01, row00, 12); | 
 |           s[4] = _mm_alignr_epi8(row02, row01, 0); | 
 |           s[5] = _mm_alignr_epi8(row02, row01, 4); | 
 |  | 
 |           __m128i res_even = convolve_12tap(s, coeffs_x); | 
 |           res_even = _mm_sra_epi32(_mm_add_epi32(res_even, round_const_x), | 
 |                                    round_shift_x); | 
 |  | 
 |           // odd pixels | 
 |           s[0] = _mm_alignr_epi8(row01, row00, 2); | 
 |           s[1] = _mm_alignr_epi8(row01, row00, 6); | 
 |           s[2] = _mm_alignr_epi8(row01, row00, 10); | 
 |           s[3] = _mm_alignr_epi8(row01, row00, 14); | 
 |           s[4] = _mm_alignr_epi8(row02, row01, 2); | 
 |           s[5] = _mm_alignr_epi8(row02, row01, 6); | 
 |  | 
 |           __m128i res_odd = convolve_12tap(s, coeffs_x); | 
 |           res_odd = _mm_sra_epi32(_mm_add_epi32(res_odd, round_const_x), | 
 |                                   round_shift_x); | 
 |  | 
 |           __m128i res_even1 = _mm_packs_epi32(res_even, res_even); | 
 |           __m128i res_odd1 = _mm_packs_epi32(res_odd, res_odd); | 
 |           __m128i res = _mm_unpacklo_epi16(res_even1, res_odd1); | 
 |  | 
 |           _mm_store_si128((__m128i *)&im_block[i * im_stride], res); | 
 |         } | 
 |       } | 
 |  | 
 |       /* Vertical filter */ | 
 |       { | 
 |         __m128i s0 = _mm_loadu_si128((__m128i *)(im_block + 0 * im_stride)); | 
 |         __m128i s1 = _mm_loadu_si128((__m128i *)(im_block + 1 * im_stride)); | 
 |         __m128i s2 = _mm_loadu_si128((__m128i *)(im_block + 2 * im_stride)); | 
 |         __m128i s3 = _mm_loadu_si128((__m128i *)(im_block + 3 * im_stride)); | 
 |         __m128i s4 = _mm_loadu_si128((__m128i *)(im_block + 4 * im_stride)); | 
 |         __m128i s5 = _mm_loadu_si128((__m128i *)(im_block + 5 * im_stride)); | 
 |         __m128i s6 = _mm_loadu_si128((__m128i *)(im_block + 6 * im_stride)); | 
 |         __m128i s7 = _mm_loadu_si128((__m128i *)(im_block + 7 * im_stride)); | 
 |         __m128i s8 = _mm_loadu_si128((__m128i *)(im_block + 8 * im_stride)); | 
 |         __m128i s9 = _mm_loadu_si128((__m128i *)(im_block + 9 * im_stride)); | 
 |         __m128i s10 = _mm_loadu_si128((__m128i *)(im_block + 10 * im_stride)); | 
 |  | 
 |         s[0] = _mm_unpacklo_epi16(s0, s1); | 
 |         s[1] = _mm_unpacklo_epi16(s2, s3); | 
 |         s[2] = _mm_unpacklo_epi16(s4, s5); | 
 |         s[3] = _mm_unpacklo_epi16(s6, s7); | 
 |         s[4] = _mm_unpacklo_epi16(s8, s9); | 
 |  | 
 |         s[6] = _mm_unpackhi_epi16(s0, s1); | 
 |         s[7] = _mm_unpackhi_epi16(s2, s3); | 
 |         s[8] = _mm_unpackhi_epi16(s4, s5); | 
 |         s[9] = _mm_unpackhi_epi16(s6, s7); | 
 |         s[10] = _mm_unpackhi_epi16(s8, s9); | 
 |  | 
 |         s[12] = _mm_unpacklo_epi16(s1, s2); | 
 |         s[13] = _mm_unpacklo_epi16(s3, s4); | 
 |         s[14] = _mm_unpacklo_epi16(s5, s6); | 
 |         s[15] = _mm_unpacklo_epi16(s7, s8); | 
 |         s[16] = _mm_unpacklo_epi16(s9, s10); | 
 |  | 
 |         s[18] = _mm_unpackhi_epi16(s1, s2); | 
 |         s[19] = _mm_unpackhi_epi16(s3, s4); | 
 |         s[20] = _mm_unpackhi_epi16(s5, s6); | 
 |         s[21] = _mm_unpackhi_epi16(s7, s8); | 
 |         s[22] = _mm_unpackhi_epi16(s9, s10); | 
 |  | 
 |         for (i = 0; i < h; i += 2) { | 
 |           const int16_t *data = &im_block[i * im_stride]; | 
 |  | 
 |           __m128i s11 = _mm_loadu_si128((__m128i *)(data + 11 * im_stride)); | 
 |           __m128i s12 = _mm_loadu_si128((__m128i *)(data + 12 * im_stride)); | 
 |  | 
 |           s[5] = _mm_unpacklo_epi16(s10, s11); | 
 |           s[11] = _mm_unpackhi_epi16(s10, s11); | 
 |  | 
 |           s[17] = _mm_unpacklo_epi16(s11, s12); | 
 |           s[23] = _mm_unpackhi_epi16(s11, s12); | 
 |  | 
 |           const __m128i res_a0 = convolve_12tap(s, coeffs_y); | 
 |           __m128i res_a_round0 = _mm_sra_epi32( | 
 |               _mm_add_epi32(res_a0, round_const_y), round_shift_y); | 
 |           res_a_round0 = _mm_sra_epi32( | 
 |               _mm_add_epi32(res_a_round0, round_const_bits), round_shift_bits); | 
 |  | 
 |           const __m128i res_a1 = convolve_12tap(s + 12, coeffs_y); | 
 |           __m128i res_a_round1 = _mm_sra_epi32( | 
 |               _mm_add_epi32(res_a1, round_const_y), round_shift_y); | 
 |           res_a_round1 = _mm_sra_epi32( | 
 |               _mm_add_epi32(res_a_round1, round_const_bits), round_shift_bits); | 
 |  | 
 |           if (w - j > 4) { | 
 |             const __m128i res_b0 = convolve_12tap(s + 6, coeffs_y); | 
 |             __m128i res_b_round0 = _mm_sra_epi32( | 
 |                 _mm_add_epi32(res_b0, round_const_y), round_shift_y); | 
 |             res_b_round0 = | 
 |                 _mm_sra_epi32(_mm_add_epi32(res_b_round0, round_const_bits), | 
 |                               round_shift_bits); | 
 |  | 
 |             const __m128i res_b1 = convolve_12tap(s + 18, coeffs_y); | 
 |             __m128i res_b_round1 = _mm_sra_epi32( | 
 |                 _mm_add_epi32(res_b1, round_const_y), round_shift_y); | 
 |             res_b_round1 = | 
 |                 _mm_sra_epi32(_mm_add_epi32(res_b_round1, round_const_bits), | 
 |                               round_shift_bits); | 
 |  | 
 |             __m128i res_16bit0 = _mm_packs_epi32(res_a_round0, res_b_round0); | 
 |             res_16bit0 = _mm_min_epi16(res_16bit0, clip_pixel); | 
 |             res_16bit0 = _mm_max_epi16(res_16bit0, zero); | 
 |  | 
 |             __m128i res_16bit1 = _mm_packs_epi32(res_a_round1, res_b_round1); | 
 |             res_16bit1 = _mm_min_epi16(res_16bit1, clip_pixel); | 
 |             res_16bit1 = _mm_max_epi16(res_16bit1, zero); | 
 |  | 
 |             _mm_storeu_si128((__m128i *)&dst[i * dst_stride + j], res_16bit0); | 
 |             _mm_storeu_si128((__m128i *)&dst[i * dst_stride + j + dst_stride], | 
 |                              res_16bit1); | 
 |           } else if (w == 4) { | 
 |             res_a_round0 = _mm_packs_epi32(res_a_round0, res_a_round0); | 
 |             res_a_round0 = _mm_min_epi16(res_a_round0, clip_pixel); | 
 |             res_a_round0 = _mm_max_epi16(res_a_round0, zero); | 
 |  | 
 |             res_a_round1 = _mm_packs_epi32(res_a_round1, res_a_round1); | 
 |             res_a_round1 = _mm_min_epi16(res_a_round1, clip_pixel); | 
 |             res_a_round1 = _mm_max_epi16(res_a_round1, zero); | 
 |  | 
 |             _mm_storel_epi64((__m128i *)&dst[i * dst_stride + j], res_a_round0); | 
 |             _mm_storel_epi64((__m128i *)&dst[i * dst_stride + j + dst_stride], | 
 |                              res_a_round1); | 
 |           } else { | 
 |             res_a_round0 = _mm_packs_epi32(res_a_round0, res_a_round0); | 
 |             res_a_round0 = _mm_min_epi16(res_a_round0, clip_pixel); | 
 |             res_a_round0 = _mm_max_epi16(res_a_round0, zero); | 
 |  | 
 |             res_a_round1 = _mm_packs_epi32(res_a_round1, res_a_round1); | 
 |             res_a_round1 = _mm_min_epi16(res_a_round1, clip_pixel); | 
 |             res_a_round1 = _mm_max_epi16(res_a_round1, zero); | 
 |  | 
 |             *((int *)(&dst[i * dst_stride + j])) = | 
 |                 _mm_cvtsi128_si32(res_a_round0); | 
 |  | 
 |             *((int *)(&dst[i * dst_stride + j + dst_stride])) = | 
 |                 _mm_cvtsi128_si32(res_a_round1); | 
 |           } | 
 |           s[0] = s[1]; | 
 |           s[1] = s[2]; | 
 |           s[2] = s[3]; | 
 |           s[3] = s[4]; | 
 |           s[4] = s[5]; | 
 |  | 
 |           s[6] = s[7]; | 
 |           s[7] = s[8]; | 
 |           s[8] = s[9]; | 
 |           s[9] = s[10]; | 
 |           s[10] = s[11]; | 
 |  | 
 |           s[12] = s[13]; | 
 |           s[13] = s[14]; | 
 |           s[14] = s[15]; | 
 |           s[15] = s[16]; | 
 |           s[16] = s[17]; | 
 |  | 
 |           s[18] = s[19]; | 
 |           s[19] = s[20]; | 
 |           s[20] = s[21]; | 
 |           s[21] = s[22]; | 
 |           s[22] = s[23]; | 
 |  | 
 |           s10 = s12; | 
 |         } | 
 |       } | 
 |     } | 
 |   } else { | 
 |     __m128i coeffs_x[4], coeffs_y[4], s[16]; | 
 |     prepare_coeffs(filter_params_x, subpel_x_qn, coeffs_x); | 
 |     prepare_coeffs(filter_params_y, subpel_y_qn, coeffs_y); | 
 |  | 
 |     for (j = 0; j < w; j += 8) { | 
 |       /* Horizontal filter */ | 
 |       { | 
 |         for (i = 0; i < im_h; i += 1) { | 
 |           const __m128i row00 = | 
 |               _mm_loadu_si128((__m128i *)&src_ptr[i * src_stride + j]); | 
 |           const __m128i row01 = | 
 |               _mm_loadu_si128((__m128i *)&src_ptr[i * src_stride + (j + 8)]); | 
 |  | 
 |           // even pixels | 
 |           s[0] = _mm_alignr_epi8(row01, row00, 0); | 
 |           s[1] = _mm_alignr_epi8(row01, row00, 4); | 
 |           s[2] = _mm_alignr_epi8(row01, row00, 8); | 
 |           s[3] = _mm_alignr_epi8(row01, row00, 12); | 
 |  | 
 |           __m128i res_even = convolve(s, coeffs_x); | 
 |           res_even = _mm_sra_epi32(_mm_add_epi32(res_even, round_const_x), | 
 |                                    round_shift_x); | 
 |  | 
 |           // odd pixels | 
 |           s[0] = _mm_alignr_epi8(row01, row00, 2); | 
 |           s[1] = _mm_alignr_epi8(row01, row00, 6); | 
 |           s[2] = _mm_alignr_epi8(row01, row00, 10); | 
 |           s[3] = _mm_alignr_epi8(row01, row00, 14); | 
 |  | 
 |           __m128i res_odd = convolve(s, coeffs_x); | 
 |           res_odd = _mm_sra_epi32(_mm_add_epi32(res_odd, round_const_x), | 
 |                                   round_shift_x); | 
 |  | 
 |           __m128i res_even1 = _mm_packs_epi32(res_even, res_even); | 
 |           __m128i res_odd1 = _mm_packs_epi32(res_odd, res_odd); | 
 |           __m128i res = _mm_unpacklo_epi16(res_even1, res_odd1); | 
 |  | 
 |           _mm_store_si128((__m128i *)&im_block[i * im_stride], res); | 
 |         } | 
 |       } | 
 |  | 
 |       /* Vertical filter */ | 
 |       { | 
 |         __m128i s0 = _mm_loadu_si128((__m128i *)(im_block + 0 * im_stride)); | 
 |         __m128i s1 = _mm_loadu_si128((__m128i *)(im_block + 1 * im_stride)); | 
 |         __m128i s2 = _mm_loadu_si128((__m128i *)(im_block + 2 * im_stride)); | 
 |         __m128i s3 = _mm_loadu_si128((__m128i *)(im_block + 3 * im_stride)); | 
 |         __m128i s4 = _mm_loadu_si128((__m128i *)(im_block + 4 * im_stride)); | 
 |         __m128i s5 = _mm_loadu_si128((__m128i *)(im_block + 5 * im_stride)); | 
 |         __m128i s6 = _mm_loadu_si128((__m128i *)(im_block + 6 * im_stride)); | 
 |  | 
 |         s[0] = _mm_unpacklo_epi16(s0, s1); | 
 |         s[1] = _mm_unpacklo_epi16(s2, s3); | 
 |         s[2] = _mm_unpacklo_epi16(s4, s5); | 
 |  | 
 |         s[4] = _mm_unpackhi_epi16(s0, s1); | 
 |         s[5] = _mm_unpackhi_epi16(s2, s3); | 
 |         s[6] = _mm_unpackhi_epi16(s4, s5); | 
 |  | 
 |         s[0 + 8] = _mm_unpacklo_epi16(s1, s2); | 
 |         s[1 + 8] = _mm_unpacklo_epi16(s3, s4); | 
 |         s[2 + 8] = _mm_unpacklo_epi16(s5, s6); | 
 |  | 
 |         s[4 + 8] = _mm_unpackhi_epi16(s1, s2); | 
 |         s[5 + 8] = _mm_unpackhi_epi16(s3, s4); | 
 |         s[6 + 8] = _mm_unpackhi_epi16(s5, s6); | 
 |  | 
 |         for (i = 0; i < h; i += 2) { | 
 |           const int16_t *data = &im_block[i * im_stride]; | 
 |  | 
 |           __m128i s7 = _mm_loadu_si128((__m128i *)(data + 7 * im_stride)); | 
 |           __m128i s8 = _mm_loadu_si128((__m128i *)(data + 8 * im_stride)); | 
 |  | 
 |           s[3] = _mm_unpacklo_epi16(s6, s7); | 
 |           s[7] = _mm_unpackhi_epi16(s6, s7); | 
 |  | 
 |           s[3 + 8] = _mm_unpacklo_epi16(s7, s8); | 
 |           s[7 + 8] = _mm_unpackhi_epi16(s7, s8); | 
 |  | 
 |           const __m128i res_a0 = convolve(s, coeffs_y); | 
 |           __m128i res_a_round0 = _mm_sra_epi32( | 
 |               _mm_add_epi32(res_a0, round_const_y), round_shift_y); | 
 |           res_a_round0 = _mm_sra_epi32( | 
 |               _mm_add_epi32(res_a_round0, round_const_bits), round_shift_bits); | 
 |  | 
 |           const __m128i res_a1 = convolve(s + 8, coeffs_y); | 
 |           __m128i res_a_round1 = _mm_sra_epi32( | 
 |               _mm_add_epi32(res_a1, round_const_y), round_shift_y); | 
 |           res_a_round1 = _mm_sra_epi32( | 
 |               _mm_add_epi32(res_a_round1, round_const_bits), round_shift_bits); | 
 |  | 
 |           if (w - j > 4) { | 
 |             const __m128i res_b0 = convolve(s + 4, coeffs_y); | 
 |             __m128i res_b_round0 = _mm_sra_epi32( | 
 |                 _mm_add_epi32(res_b0, round_const_y), round_shift_y); | 
 |             res_b_round0 = | 
 |                 _mm_sra_epi32(_mm_add_epi32(res_b_round0, round_const_bits), | 
 |                               round_shift_bits); | 
 |  | 
 |             const __m128i res_b1 = convolve(s + 4 + 8, coeffs_y); | 
 |             __m128i res_b_round1 = _mm_sra_epi32( | 
 |                 _mm_add_epi32(res_b1, round_const_y), round_shift_y); | 
 |             res_b_round1 = | 
 |                 _mm_sra_epi32(_mm_add_epi32(res_b_round1, round_const_bits), | 
 |                               round_shift_bits); | 
 |  | 
 |             __m128i res_16bit0 = _mm_packs_epi32(res_a_round0, res_b_round0); | 
 |             res_16bit0 = _mm_min_epi16(res_16bit0, clip_pixel); | 
 |             res_16bit0 = _mm_max_epi16(res_16bit0, zero); | 
 |  | 
 |             __m128i res_16bit1 = _mm_packs_epi32(res_a_round1, res_b_round1); | 
 |             res_16bit1 = _mm_min_epi16(res_16bit1, clip_pixel); | 
 |             res_16bit1 = _mm_max_epi16(res_16bit1, zero); | 
 |  | 
 |             _mm_storeu_si128((__m128i *)&dst[i * dst_stride + j], res_16bit0); | 
 |             _mm_storeu_si128((__m128i *)&dst[i * dst_stride + j + dst_stride], | 
 |                              res_16bit1); | 
 |           } else if (w == 4) { | 
 |             res_a_round0 = _mm_packs_epi32(res_a_round0, res_a_round0); | 
 |             res_a_round0 = _mm_min_epi16(res_a_round0, clip_pixel); | 
 |             res_a_round0 = _mm_max_epi16(res_a_round0, zero); | 
 |  | 
 |             res_a_round1 = _mm_packs_epi32(res_a_round1, res_a_round1); | 
 |             res_a_round1 = _mm_min_epi16(res_a_round1, clip_pixel); | 
 |             res_a_round1 = _mm_max_epi16(res_a_round1, zero); | 
 |  | 
 |             _mm_storel_epi64((__m128i *)&dst[i * dst_stride + j], res_a_round0); | 
 |             _mm_storel_epi64((__m128i *)&dst[i * dst_stride + j + dst_stride], | 
 |                              res_a_round1); | 
 |           } else { | 
 |             res_a_round0 = _mm_packs_epi32(res_a_round0, res_a_round0); | 
 |             res_a_round0 = _mm_min_epi16(res_a_round0, clip_pixel); | 
 |             res_a_round0 = _mm_max_epi16(res_a_round0, zero); | 
 |  | 
 |             res_a_round1 = _mm_packs_epi32(res_a_round1, res_a_round1); | 
 |             res_a_round1 = _mm_min_epi16(res_a_round1, clip_pixel); | 
 |             res_a_round1 = _mm_max_epi16(res_a_round1, zero); | 
 |  | 
 |             *((int *)(&dst[i * dst_stride + j])) = | 
 |                 _mm_cvtsi128_si32(res_a_round0); | 
 |  | 
 |             *((int *)(&dst[i * dst_stride + j + dst_stride])) = | 
 |                 _mm_cvtsi128_si32(res_a_round1); | 
 |           } | 
 |           s[0] = s[1]; | 
 |           s[1] = s[2]; | 
 |           s[2] = s[3]; | 
 |  | 
 |           s[4] = s[5]; | 
 |           s[5] = s[6]; | 
 |           s[6] = s[7]; | 
 |  | 
 |           s[0 + 8] = s[1 + 8]; | 
 |           s[1 + 8] = s[2 + 8]; | 
 |           s[2 + 8] = s[3 + 8]; | 
 |  | 
 |           s[4 + 8] = s[5 + 8]; | 
 |           s[5 + 8] = s[6 + 8]; | 
 |           s[6 + 8] = s[7 + 8]; | 
 |  | 
 |           s6 = s8; | 
 |         } | 
 |       } | 
 |     } | 
 |   } | 
 | } |