/* * jfdctint-neon.c - accurate integer FDCT (Arm Neon) * * Copyright (C) 2020, Arm Limited. All Rights Reserved. * Copyright (C) 2020, D. R. Commander. All Rights Reserved. * * This software is provided 'as-is', without any express or implied * warranty. In no event will the authors be held liable for any damages * arising from the use of this software. * * Permission is granted to anyone to use this software for any purpose, * including commercial applications, and to alter it and redistribute it * freely, subject to the following restrictions: * * 1. The origin of this software must not be misrepresented; you must not * claim that you wrote the original software. If you use this software * in a product, an acknowledgment in the product documentation would be * appreciated but is not required. * 2. Altered source versions must be plainly marked as such, and must not be * misrepresented as being the original software. * 3. This notice may not be removed or altered from any source distribution. */ #define JPEG_INTERNALS #include "../../jinclude.h" #include "../../jpeglib.h" #include "../../jsimd.h" #include "../../jdct.h" #include "../../jsimddct.h" #include "../jsimd.h" #include "align.h" #include "neon-compat.h" #include /* jsimd_fdct_islow_neon() performs a slower but more accurate forward DCT * (Discrete Cosine Transform) on one block of samples. It uses the same * calculations and produces exactly the same output as IJG's original * jpeg_fdct_islow() function, which can be found in jfdctint.c. * * Scaled integer constants are used to avoid floating-point arithmetic: * 0.298631336 = 2446 * 2^-13 * 0.390180644 = 3196 * 2^-13 * 0.541196100 = 4433 * 2^-13 * 0.765366865 = 6270 * 2^-13 * 0.899976223 = 7373 * 2^-13 * 1.175875602 = 9633 * 2^-13 * 1.501321110 = 12299 * 2^-13 * 1.847759065 = 15137 * 2^-13 * 1.961570560 = 16069 * 2^-13 * 2.053119869 = 16819 * 2^-13 * 2.562915447 = 20995 * 2^-13 * 3.072711026 = 25172 * 2^-13 * * See jfdctint.c for further details of the DCT algorithm. Where possible, * the variable names and comments here in jsimd_fdct_islow_neon() match up * with those in jpeg_fdct_islow(). */ #define CONST_BITS 13 #define PASS1_BITS 2 #define DESCALE_P1 (CONST_BITS - PASS1_BITS) #define DESCALE_P2 (CONST_BITS + PASS1_BITS) #define F_0_298 2446 #define F_0_390 3196 #define F_0_541 4433 #define F_0_765 6270 #define F_0_899 7373 #define F_1_175 9633 #define F_1_501 12299 #define F_1_847 15137 #define F_1_961 16069 #define F_2_053 16819 #define F_2_562 20995 #define F_3_072 25172 ALIGN(16) static const int16_t jsimd_fdct_islow_neon_consts[] = { F_0_298, -F_0_390, F_0_541, F_0_765, -F_0_899, F_1_175, F_1_501, -F_1_847, -F_1_961, F_2_053, -F_2_562, F_3_072 }; void jsimd_fdct_islow_neon(DCTELEM *data) { /* Load DCT constants. */ #ifdef HAVE_VLD1_S16_X3 const int16x4x3_t consts = vld1_s16_x3(jsimd_fdct_islow_neon_consts); #else /* GCC does not currently support the intrinsic vld1__x3(). */ const int16x4_t consts1 = vld1_s16(jsimd_fdct_islow_neon_consts); const int16x4_t consts2 = vld1_s16(jsimd_fdct_islow_neon_consts + 4); const int16x4_t consts3 = vld1_s16(jsimd_fdct_islow_neon_consts + 8); const int16x4x3_t consts = { { consts1, consts2, consts3 } }; #endif /* Load an 8x8 block of samples into Neon registers. De-interleaving loads * are used, followed by vuzp to transpose the block such that we have a * column of samples per vector - allowing all rows to be processed at once. */ int16x8x4_t s_rows_0123 = vld4q_s16(data); int16x8x4_t s_rows_4567 = vld4q_s16(data + 4 * DCTSIZE); int16x8x2_t cols_04 = vuzpq_s16(s_rows_0123.val[0], s_rows_4567.val[0]); int16x8x2_t cols_15 = vuzpq_s16(s_rows_0123.val[1], s_rows_4567.val[1]); int16x8x2_t cols_26 = vuzpq_s16(s_rows_0123.val[2], s_rows_4567.val[2]); int16x8x2_t cols_37 = vuzpq_s16(s_rows_0123.val[3], s_rows_4567.val[3]); int16x8_t col0 = cols_04.val[0]; int16x8_t col1 = cols_15.val[0]; int16x8_t col2 = cols_26.val[0]; int16x8_t col3 = cols_37.val[0]; int16x8_t col4 = cols_04.val[1]; int16x8_t col5 = cols_15.val[1]; int16x8_t col6 = cols_26.val[1]; int16x8_t col7 = cols_37.val[1]; /* Pass 1: process rows. */ int16x8_t tmp0 = vaddq_s16(col0, col7); int16x8_t tmp7 = vsubq_s16(col0, col7); int16x8_t tmp1 = vaddq_s16(col1, col6); int16x8_t tmp6 = vsubq_s16(col1, col6); int16x8_t tmp2 = vaddq_s16(col2, col5); int16x8_t tmp5 = vsubq_s16(col2, col5); int16x8_t tmp3 = vaddq_s16(col3, col4); int16x8_t tmp4 = vsubq_s16(col3, col4); /* Even part */ int16x8_t tmp10 = vaddq_s16(tmp0, tmp3); int16x8_t tmp13 = vsubq_s16(tmp0, tmp3); int16x8_t tmp11 = vaddq_s16(tmp1, tmp2); int16x8_t tmp12 = vsubq_s16(tmp1, tmp2); col0 = vshlq_n_s16(vaddq_s16(tmp10, tmp11), PASS1_BITS); col4 = vshlq_n_s16(vsubq_s16(tmp10, tmp11), PASS1_BITS); int16x8_t tmp12_add_tmp13 = vaddq_s16(tmp12, tmp13); int32x4_t z1_l = vmull_lane_s16(vget_low_s16(tmp12_add_tmp13), consts.val[0], 2); int32x4_t z1_h = vmull_lane_s16(vget_high_s16(tmp12_add_tmp13), consts.val[0], 2); int32x4_t col2_scaled_l = vmlal_lane_s16(z1_l, vget_low_s16(tmp13), consts.val[0], 3); int32x4_t col2_scaled_h = vmlal_lane_s16(z1_h, vget_high_s16(tmp13), consts.val[0], 3); col2 = vcombine_s16(vrshrn_n_s32(col2_scaled_l, DESCALE_P1), vrshrn_n_s32(col2_scaled_h, DESCALE_P1)); int32x4_t col6_scaled_l = vmlal_lane_s16(z1_l, vget_low_s16(tmp12), consts.val[1], 3); int32x4_t col6_scaled_h = vmlal_lane_s16(z1_h, vget_high_s16(tmp12), consts.val[1], 3); col6 = vcombine_s16(vrshrn_n_s32(col6_scaled_l, DESCALE_P1), vrshrn_n_s32(col6_scaled_h, DESCALE_P1)); /* Odd part */ int16x8_t z1 = vaddq_s16(tmp4, tmp7); int16x8_t z2 = vaddq_s16(tmp5, tmp6); int16x8_t z3 = vaddq_s16(tmp4, tmp6); int16x8_t z4 = vaddq_s16(tmp5, tmp7); /* sqrt(2) * c3 */ int32x4_t z5_l = vmull_lane_s16(vget_low_s16(z3), consts.val[1], 1); int32x4_t z5_h = vmull_lane_s16(vget_high_s16(z3), consts.val[1], 1); z5_l = vmlal_lane_s16(z5_l, vget_low_s16(z4), consts.val[1], 1); z5_h = vmlal_lane_s16(z5_h, vget_high_s16(z4), consts.val[1], 1); /* sqrt(2) * (-c1+c3+c5-c7) */ int32x4_t tmp4_l = vmull_lane_s16(vget_low_s16(tmp4), consts.val[0], 0); int32x4_t tmp4_h = vmull_lane_s16(vget_high_s16(tmp4), consts.val[0], 0); /* sqrt(2) * ( c1+c3-c5+c7) */ int32x4_t tmp5_l = vmull_lane_s16(vget_low_s16(tmp5), consts.val[2], 1); int32x4_t tmp5_h = vmull_lane_s16(vget_high_s16(tmp5), consts.val[2], 1); /* sqrt(2) * ( c1+c3+c5-c7) */ int32x4_t tmp6_l = vmull_lane_s16(vget_low_s16(tmp6), consts.val[2], 3); int32x4_t tmp6_h = vmull_lane_s16(vget_high_s16(tmp6), consts.val[2], 3); /* sqrt(2) * ( c1+c3-c5-c7) */ int32x4_t tmp7_l = vmull_lane_s16(vget_low_s16(tmp7), consts.val[1], 2); int32x4_t tmp7_h = vmull_lane_s16(vget_high_s16(tmp7), consts.val[1], 2); /* sqrt(2) * (c7-c3) */ z1_l = vmull_lane_s16(vget_low_s16(z1), consts.val[1], 0); z1_h = vmull_lane_s16(vget_high_s16(z1), consts.val[1], 0); /* sqrt(2) * (-c1-c3) */ int32x4_t z2_l = vmull_lane_s16(vget_low_s16(z2), consts.val[2], 2); int32x4_t z2_h = vmull_lane_s16(vget_high_s16(z2), consts.val[2], 2); /* sqrt(2) * (-c3-c5) */ int32x4_t z3_l = vmull_lane_s16(vget_low_s16(z3), consts.val[2], 0); int32x4_t z3_h = vmull_lane_s16(vget_high_s16(z3), consts.val[2], 0); /* sqrt(2) * (c5-c3) */ int32x4_t z4_l = vmull_lane_s16(vget_low_s16(z4), consts.val[0], 1); int32x4_t z4_h = vmull_lane_s16(vget_high_s16(z4), consts.val[0], 1); z3_l = vaddq_s32(z3_l, z5_l); z3_h = vaddq_s32(z3_h, z5_h); z4_l = vaddq_s32(z4_l, z5_l); z4_h = vaddq_s32(z4_h, z5_h); tmp4_l = vaddq_s32(tmp4_l, z1_l); tmp4_h = vaddq_s32(tmp4_h, z1_h); tmp4_l = vaddq_s32(tmp4_l, z3_l); tmp4_h = vaddq_s32(tmp4_h, z3_h); col7 = vcombine_s16(vrshrn_n_s32(tmp4_l, DESCALE_P1), vrshrn_n_s32(tmp4_h, DESCALE_P1)); tmp5_l = vaddq_s32(tmp5_l, z2_l); tmp5_h = vaddq_s32(tmp5_h, z2_h); tmp5_l = vaddq_s32(tmp5_l, z4_l); tmp5_h = vaddq_s32(tmp5_h, z4_h); col5 = vcombine_s16(vrshrn_n_s32(tmp5_l, DESCALE_P1), vrshrn_n_s32(tmp5_h, DESCALE_P1)); tmp6_l = vaddq_s32(tmp6_l, z2_l); tmp6_h = vaddq_s32(tmp6_h, z2_h); tmp6_l = vaddq_s32(tmp6_l, z3_l); tmp6_h = vaddq_s32(tmp6_h, z3_h); col3 = vcombine_s16(vrshrn_n_s32(tmp6_l, DESCALE_P1), vrshrn_n_s32(tmp6_h, DESCALE_P1)); tmp7_l = vaddq_s32(tmp7_l, z1_l); tmp7_h = vaddq_s32(tmp7_h, z1_h); tmp7_l = vaddq_s32(tmp7_l, z4_l); tmp7_h = vaddq_s32(tmp7_h, z4_h); col1 = vcombine_s16(vrshrn_n_s32(tmp7_l, DESCALE_P1), vrshrn_n_s32(tmp7_h, DESCALE_P1)); /* Transpose to work on columns in pass 2. */ int16x8x2_t cols_01 = vtrnq_s16(col0, col1); int16x8x2_t cols_23 = vtrnq_s16(col2, col3); int16x8x2_t cols_45 = vtrnq_s16(col4, col5); int16x8x2_t cols_67 = vtrnq_s16(col6, col7); int32x4x2_t cols_0145_l = vtrnq_s32(vreinterpretq_s32_s16(cols_01.val[0]), vreinterpretq_s32_s16(cols_45.val[0])); int32x4x2_t cols_0145_h = vtrnq_s32(vreinterpretq_s32_s16(cols_01.val[1]), vreinterpretq_s32_s16(cols_45.val[1])); int32x4x2_t cols_2367_l = vtrnq_s32(vreinterpretq_s32_s16(cols_23.val[0]), vreinterpretq_s32_s16(cols_67.val[0])); int32x4x2_t cols_2367_h = vtrnq_s32(vreinterpretq_s32_s16(cols_23.val[1]), vreinterpretq_s32_s16(cols_67.val[1])); int32x4x2_t rows_04 = vzipq_s32(cols_0145_l.val[0], cols_2367_l.val[0]); int32x4x2_t rows_15 = vzipq_s32(cols_0145_h.val[0], cols_2367_h.val[0]); int32x4x2_t rows_26 = vzipq_s32(cols_0145_l.val[1], cols_2367_l.val[1]); int32x4x2_t rows_37 = vzipq_s32(cols_0145_h.val[1], cols_2367_h.val[1]); int16x8_t row0 = vreinterpretq_s16_s32(rows_04.val[0]); int16x8_t row1 = vreinterpretq_s16_s32(rows_15.val[0]); int16x8_t row2 = vreinterpretq_s16_s32(rows_26.val[0]); int16x8_t row3 = vreinterpretq_s16_s32(rows_37.val[0]); int16x8_t row4 = vreinterpretq_s16_s32(rows_04.val[1]); int16x8_t row5 = vreinterpretq_s16_s32(rows_15.val[1]); int16x8_t row6 = vreinterpretq_s16_s32(rows_26.val[1]); int16x8_t row7 = vreinterpretq_s16_s32(rows_37.val[1]); /* Pass 2: process columns. */ tmp0 = vaddq_s16(row0, row7); tmp7 = vsubq_s16(row0, row7); tmp1 = vaddq_s16(row1, row6); tmp6 = vsubq_s16(row1, row6); tmp2 = vaddq_s16(row2, row5); tmp5 = vsubq_s16(row2, row5); tmp3 = vaddq_s16(row3, row4); tmp4 = vsubq_s16(row3, row4); /* Even part */ tmp10 = vaddq_s16(tmp0, tmp3); tmp13 = vsubq_s16(tmp0, tmp3); tmp11 = vaddq_s16(tmp1, tmp2); tmp12 = vsubq_s16(tmp1, tmp2); row0 = vrshrq_n_s16(vaddq_s16(tmp10, tmp11), PASS1_BITS); row4 = vrshrq_n_s16(vsubq_s16(tmp10, tmp11), PASS1_BITS); tmp12_add_tmp13 = vaddq_s16(tmp12, tmp13); z1_l = vmull_lane_s16(vget_low_s16(tmp12_add_tmp13), consts.val[0], 2); z1_h = vmull_lane_s16(vget_high_s16(tmp12_add_tmp13), consts.val[0], 2); int32x4_t row2_scaled_l = vmlal_lane_s16(z1_l, vget_low_s16(tmp13), consts.val[0], 3); int32x4_t row2_scaled_h = vmlal_lane_s16(z1_h, vget_high_s16(tmp13), consts.val[0], 3); row2 = vcombine_s16(vrshrn_n_s32(row2_scaled_l, DESCALE_P2), vrshrn_n_s32(row2_scaled_h, DESCALE_P2)); int32x4_t row6_scaled_l = vmlal_lane_s16(z1_l, vget_low_s16(tmp12), consts.val[1], 3); int32x4_t row6_scaled_h = vmlal_lane_s16(z1_h, vget_high_s16(tmp12), consts.val[1], 3); row6 = vcombine_s16(vrshrn_n_s32(row6_scaled_l, DESCALE_P2), vrshrn_n_s32(row6_scaled_h, DESCALE_P2)); /* Odd part */ z1 = vaddq_s16(tmp4, tmp7); z2 = vaddq_s16(tmp5, tmp6); z3 = vaddq_s16(tmp4, tmp6); z4 = vaddq_s16(tmp5, tmp7); /* sqrt(2) * c3 */ z5_l = vmull_lane_s16(vget_low_s16(z3), consts.val[1], 1); z5_h = vmull_lane_s16(vget_high_s16(z3), consts.val[1], 1); z5_l = vmlal_lane_s16(z5_l, vget_low_s16(z4), consts.val[1], 1); z5_h = vmlal_lane_s16(z5_h, vget_high_s16(z4), consts.val[1], 1); /* sqrt(2) * (-c1+c3+c5-c7) */ tmp4_l = vmull_lane_s16(vget_low_s16(tmp4), consts.val[0], 0); tmp4_h = vmull_lane_s16(vget_high_s16(tmp4), consts.val[0], 0); /* sqrt(2) * ( c1+c3-c5+c7) */ tmp5_l = vmull_lane_s16(vget_low_s16(tmp5), consts.val[2], 1); tmp5_h = vmull_lane_s16(vget_high_s16(tmp5), consts.val[2], 1); /* sqrt(2) * ( c1+c3+c5-c7) */ tmp6_l = vmull_lane_s16(vget_low_s16(tmp6), consts.val[2], 3); tmp6_h = vmull_lane_s16(vget_high_s16(tmp6), consts.val[2], 3); /* sqrt(2) * ( c1+c3-c5-c7) */ tmp7_l = vmull_lane_s16(vget_low_s16(tmp7), consts.val[1], 2); tmp7_h = vmull_lane_s16(vget_high_s16(tmp7), consts.val[1], 2); /* sqrt(2) * (c7-c3) */ z1_l = vmull_lane_s16(vget_low_s16(z1), consts.val[1], 0); z1_h = vmull_lane_s16(vget_high_s16(z1), consts.val[1], 0); /* sqrt(2) * (-c1-c3) */ z2_l = vmull_lane_s16(vget_low_s16(z2), consts.val[2], 2); z2_h = vmull_lane_s16(vget_high_s16(z2), consts.val[2], 2); /* sqrt(2) * (-c3-c5) */ z3_l = vmull_lane_s16(vget_low_s16(z3), consts.val[2], 0); z3_h = vmull_lane_s16(vget_high_s16(z3), consts.val[2], 0); /* sqrt(2) * (c5-c3) */ z4_l = vmull_lane_s16(vget_low_s16(z4), consts.val[0], 1); z4_h = vmull_lane_s16(vget_high_s16(z4), consts.val[0], 1); z3_l = vaddq_s32(z3_l, z5_l); z3_h = vaddq_s32(z3_h, z5_h); z4_l = vaddq_s32(z4_l, z5_l); z4_h = vaddq_s32(z4_h, z5_h); tmp4_l = vaddq_s32(tmp4_l, z1_l); tmp4_h = vaddq_s32(tmp4_h, z1_h); tmp4_l = vaddq_s32(tmp4_l, z3_l); tmp4_h = vaddq_s32(tmp4_h, z3_h); row7 = vcombine_s16(vrshrn_n_s32(tmp4_l, DESCALE_P2), vrshrn_n_s32(tmp4_h, DESCALE_P2)); tmp5_l = vaddq_s32(tmp5_l, z2_l); tmp5_h = vaddq_s32(tmp5_h, z2_h); tmp5_l = vaddq_s32(tmp5_l, z4_l); tmp5_h = vaddq_s32(tmp5_h, z4_h); row5 = vcombine_s16(vrshrn_n_s32(tmp5_l, DESCALE_P2), vrshrn_n_s32(tmp5_h, DESCALE_P2)); tmp6_l = vaddq_s32(tmp6_l, z2_l); tmp6_h = vaddq_s32(tmp6_h, z2_h); tmp6_l = vaddq_s32(tmp6_l, z3_l); tmp6_h = vaddq_s32(tmp6_h, z3_h); row3 = vcombine_s16(vrshrn_n_s32(tmp6_l, DESCALE_P2), vrshrn_n_s32(tmp6_h, DESCALE_P2)); tmp7_l = vaddq_s32(tmp7_l, z1_l); tmp7_h = vaddq_s32(tmp7_h, z1_h); tmp7_l = vaddq_s32(tmp7_l, z4_l); tmp7_h = vaddq_s32(tmp7_h, z4_h); row1 = vcombine_s16(vrshrn_n_s32(tmp7_l, DESCALE_P2), vrshrn_n_s32(tmp7_h, DESCALE_P2)); vst1q_s16(data + 0 * DCTSIZE, row0); vst1q_s16(data + 1 * DCTSIZE, row1); vst1q_s16(data + 2 * DCTSIZE, row2); vst1q_s16(data + 3 * DCTSIZE, row3); vst1q_s16(data + 4 * DCTSIZE, row4); vst1q_s16(data + 5 * DCTSIZE, row5); vst1q_s16(data + 6 * DCTSIZE, row6); vst1q_s16(data + 7 * DCTSIZE, row7); }