/* * jchuff-neon.c - Huffman entropy encoding (32-bit Arm Neon) * * Copyright (C) 2020, Arm Limited. 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. * * NOTE: All referenced figures are from * Recommendation ITU-T T.81 (1992) | ISO/IEC 10918-1:1994. */ #define JPEG_INTERNALS #include "../../../jinclude.h" #include "../../../jpeglib.h" #include "../../../jsimd.h" #include "../../../jdct.h" #include "../../../jsimddct.h" #include "../../jsimd.h" #include "../jchuff.h" #include "neon-compat.h" #include #include JOCTET *jsimd_huff_encode_one_block_neon(void *state, JOCTET *buffer, JCOEFPTR block, int last_dc_val, c_derived_tbl *dctbl, c_derived_tbl *actbl) { uint8_t block_nbits[DCTSIZE2]; uint16_t block_diff[DCTSIZE2]; /* Load rows of coefficients from DCT block in zig-zag order. */ /* Compute DC coefficient difference value. (F.1.1.5.1) */ int16x8_t row0 = vdupq_n_s16(block[0] - last_dc_val); row0 = vld1q_lane_s16(block + 1, row0, 1); row0 = vld1q_lane_s16(block + 8, row0, 2); row0 = vld1q_lane_s16(block + 16, row0, 3); row0 = vld1q_lane_s16(block + 9, row0, 4); row0 = vld1q_lane_s16(block + 2, row0, 5); row0 = vld1q_lane_s16(block + 3, row0, 6); row0 = vld1q_lane_s16(block + 10, row0, 7); int16x8_t row1 = vld1q_dup_s16(block + 17); row1 = vld1q_lane_s16(block + 24, row1, 1); row1 = vld1q_lane_s16(block + 32, row1, 2); row1 = vld1q_lane_s16(block + 25, row1, 3); row1 = vld1q_lane_s16(block + 18, row1, 4); row1 = vld1q_lane_s16(block + 11, row1, 5); row1 = vld1q_lane_s16(block + 4, row1, 6); row1 = vld1q_lane_s16(block + 5, row1, 7); int16x8_t row2 = vld1q_dup_s16(block + 12); row2 = vld1q_lane_s16(block + 19, row2, 1); row2 = vld1q_lane_s16(block + 26, row2, 2); row2 = vld1q_lane_s16(block + 33, row2, 3); row2 = vld1q_lane_s16(block + 40, row2, 4); row2 = vld1q_lane_s16(block + 48, row2, 5); row2 = vld1q_lane_s16(block + 41, row2, 6); row2 = vld1q_lane_s16(block + 34, row2, 7); int16x8_t row3 = vld1q_dup_s16(block + 27); row3 = vld1q_lane_s16(block + 20, row3, 1); row3 = vld1q_lane_s16(block + 13, row3, 2); row3 = vld1q_lane_s16(block + 6, row3, 3); row3 = vld1q_lane_s16(block + 7, row3, 4); row3 = vld1q_lane_s16(block + 14, row3, 5); row3 = vld1q_lane_s16(block + 21, row3, 6); row3 = vld1q_lane_s16(block + 28, row3, 7); int16x8_t abs_row0 = vabsq_s16(row0); int16x8_t abs_row1 = vabsq_s16(row1); int16x8_t abs_row2 = vabsq_s16(row2); int16x8_t abs_row3 = vabsq_s16(row3); int16x8_t row0_lz = vclzq_s16(abs_row0); int16x8_t row1_lz = vclzq_s16(abs_row1); int16x8_t row2_lz = vclzq_s16(abs_row2); int16x8_t row3_lz = vclzq_s16(abs_row3); /* Compute number of bits required to represent each coefficient. */ uint8x8_t row0_nbits = vsub_u8(vdup_n_u8(16), vmovn_u16(vreinterpretq_u16_s16(row0_lz))); uint8x8_t row1_nbits = vsub_u8(vdup_n_u8(16), vmovn_u16(vreinterpretq_u16_s16(row1_lz))); uint8x8_t row2_nbits = vsub_u8(vdup_n_u8(16), vmovn_u16(vreinterpretq_u16_s16(row2_lz))); uint8x8_t row3_nbits = vsub_u8(vdup_n_u8(16), vmovn_u16(vreinterpretq_u16_s16(row3_lz))); vst1_u8(block_nbits + 0 * DCTSIZE, row0_nbits); vst1_u8(block_nbits + 1 * DCTSIZE, row1_nbits); vst1_u8(block_nbits + 2 * DCTSIZE, row2_nbits); vst1_u8(block_nbits + 3 * DCTSIZE, row3_nbits); uint16x8_t row0_mask = vshlq_u16(vreinterpretq_u16_s16(vshrq_n_s16(row0, 15)), vnegq_s16(row0_lz)); uint16x8_t row1_mask = vshlq_u16(vreinterpretq_u16_s16(vshrq_n_s16(row1, 15)), vnegq_s16(row1_lz)); uint16x8_t row2_mask = vshlq_u16(vreinterpretq_u16_s16(vshrq_n_s16(row2, 15)), vnegq_s16(row2_lz)); uint16x8_t row3_mask = vshlq_u16(vreinterpretq_u16_s16(vshrq_n_s16(row3, 15)), vnegq_s16(row3_lz)); uint16x8_t row0_diff = veorq_u16(vreinterpretq_u16_s16(abs_row0), row0_mask); uint16x8_t row1_diff = veorq_u16(vreinterpretq_u16_s16(abs_row1), row1_mask); uint16x8_t row2_diff = veorq_u16(vreinterpretq_u16_s16(abs_row2), row2_mask); uint16x8_t row3_diff = veorq_u16(vreinterpretq_u16_s16(abs_row3), row3_mask); /* Store diff values for rows 0, 1, 2, and 3. */ vst1q_u16(block_diff + 0 * DCTSIZE, row0_diff); vst1q_u16(block_diff + 1 * DCTSIZE, row1_diff); vst1q_u16(block_diff + 2 * DCTSIZE, row2_diff); vst1q_u16(block_diff + 3 * DCTSIZE, row3_diff); /* Load last four rows of coefficients from DCT block in zig-zag order. */ int16x8_t row4 = vld1q_dup_s16(block + 35); row4 = vld1q_lane_s16(block + 42, row4, 1); row4 = vld1q_lane_s16(block + 49, row4, 2); row4 = vld1q_lane_s16(block + 56, row4, 3); row4 = vld1q_lane_s16(block + 57, row4, 4); row4 = vld1q_lane_s16(block + 50, row4, 5); row4 = vld1q_lane_s16(block + 43, row4, 6); row4 = vld1q_lane_s16(block + 36, row4, 7); int16x8_t row5 = vld1q_dup_s16(block + 29); row5 = vld1q_lane_s16(block + 22, row5, 1); row5 = vld1q_lane_s16(block + 15, row5, 2); row5 = vld1q_lane_s16(block + 23, row5, 3); row5 = vld1q_lane_s16(block + 30, row5, 4); row5 = vld1q_lane_s16(block + 37, row5, 5); row5 = vld1q_lane_s16(block + 44, row5, 6); row5 = vld1q_lane_s16(block + 51, row5, 7); int16x8_t row6 = vld1q_dup_s16(block + 58); row6 = vld1q_lane_s16(block + 59, row6, 1); row6 = vld1q_lane_s16(block + 52, row6, 2); row6 = vld1q_lane_s16(block + 45, row6, 3); row6 = vld1q_lane_s16(block + 38, row6, 4); row6 = vld1q_lane_s16(block + 31, row6, 5); row6 = vld1q_lane_s16(block + 39, row6, 6); row6 = vld1q_lane_s16(block + 46, row6, 7); int16x8_t row7 = vld1q_dup_s16(block + 53); row7 = vld1q_lane_s16(block + 60, row7, 1); row7 = vld1q_lane_s16(block + 61, row7, 2); row7 = vld1q_lane_s16(block + 54, row7, 3); row7 = vld1q_lane_s16(block + 47, row7, 4); row7 = vld1q_lane_s16(block + 55, row7, 5); row7 = vld1q_lane_s16(block + 62, row7, 6); row7 = vld1q_lane_s16(block + 63, row7, 7); int16x8_t abs_row4 = vabsq_s16(row4); int16x8_t abs_row5 = vabsq_s16(row5); int16x8_t abs_row6 = vabsq_s16(row6); int16x8_t abs_row7 = vabsq_s16(row7); int16x8_t row4_lz = vclzq_s16(abs_row4); int16x8_t row5_lz = vclzq_s16(abs_row5); int16x8_t row6_lz = vclzq_s16(abs_row6); int16x8_t row7_lz = vclzq_s16(abs_row7); /* Compute number of bits required to represent each coefficient. */ uint8x8_t row4_nbits = vsub_u8(vdup_n_u8(16), vmovn_u16(vreinterpretq_u16_s16(row4_lz))); uint8x8_t row5_nbits = vsub_u8(vdup_n_u8(16), vmovn_u16(vreinterpretq_u16_s16(row5_lz))); uint8x8_t row6_nbits = vsub_u8(vdup_n_u8(16), vmovn_u16(vreinterpretq_u16_s16(row6_lz))); uint8x8_t row7_nbits = vsub_u8(vdup_n_u8(16), vmovn_u16(vreinterpretq_u16_s16(row7_lz))); vst1_u8(block_nbits + 4 * DCTSIZE, row4_nbits); vst1_u8(block_nbits + 5 * DCTSIZE, row5_nbits); vst1_u8(block_nbits + 6 * DCTSIZE, row6_nbits); vst1_u8(block_nbits + 7 * DCTSIZE, row7_nbits); uint16x8_t row4_mask = vshlq_u16(vreinterpretq_u16_s16(vshrq_n_s16(row4, 15)), vnegq_s16(row4_lz)); uint16x8_t row5_mask = vshlq_u16(vreinterpretq_u16_s16(vshrq_n_s16(row5, 15)), vnegq_s16(row5_lz)); uint16x8_t row6_mask = vshlq_u16(vreinterpretq_u16_s16(vshrq_n_s16(row6, 15)), vnegq_s16(row6_lz)); uint16x8_t row7_mask = vshlq_u16(vreinterpretq_u16_s16(vshrq_n_s16(row7, 15)), vnegq_s16(row7_lz)); uint16x8_t row4_diff = veorq_u16(vreinterpretq_u16_s16(abs_row4), row4_mask); uint16x8_t row5_diff = veorq_u16(vreinterpretq_u16_s16(abs_row5), row5_mask); uint16x8_t row6_diff = veorq_u16(vreinterpretq_u16_s16(abs_row6), row6_mask); uint16x8_t row7_diff = veorq_u16(vreinterpretq_u16_s16(abs_row7), row7_mask); /* Store diff values for rows 4, 5, 6, and 7. */ vst1q_u16(block_diff + 4 * DCTSIZE, row4_diff); vst1q_u16(block_diff + 5 * DCTSIZE, row5_diff); vst1q_u16(block_diff + 6 * DCTSIZE, row6_diff); vst1q_u16(block_diff + 7 * DCTSIZE, row7_diff); /* Construct bitmap to accelerate encoding of AC coefficients. A set bit * means that the corresponding coefficient != 0. */ uint8x8_t row0_nbits_gt0 = vcgt_u8(row0_nbits, vdup_n_u8(0)); uint8x8_t row1_nbits_gt0 = vcgt_u8(row1_nbits, vdup_n_u8(0)); uint8x8_t row2_nbits_gt0 = vcgt_u8(row2_nbits, vdup_n_u8(0)); uint8x8_t row3_nbits_gt0 = vcgt_u8(row3_nbits, vdup_n_u8(0)); uint8x8_t row4_nbits_gt0 = vcgt_u8(row4_nbits, vdup_n_u8(0)); uint8x8_t row5_nbits_gt0 = vcgt_u8(row5_nbits, vdup_n_u8(0)); uint8x8_t row6_nbits_gt0 = vcgt_u8(row6_nbits, vdup_n_u8(0)); uint8x8_t row7_nbits_gt0 = vcgt_u8(row7_nbits, vdup_n_u8(0)); /* { 0x80, 0x40, 0x20, 0x10, 0x08, 0x04, 0x02, 0x01 } */ const uint8x8_t bitmap_mask = vreinterpret_u8_u64(vmov_n_u64(0x0102040810204080)); row0_nbits_gt0 = vand_u8(row0_nbits_gt0, bitmap_mask); row1_nbits_gt0 = vand_u8(row1_nbits_gt0, bitmap_mask); row2_nbits_gt0 = vand_u8(row2_nbits_gt0, bitmap_mask); row3_nbits_gt0 = vand_u8(row3_nbits_gt0, bitmap_mask); row4_nbits_gt0 = vand_u8(row4_nbits_gt0, bitmap_mask); row5_nbits_gt0 = vand_u8(row5_nbits_gt0, bitmap_mask); row6_nbits_gt0 = vand_u8(row6_nbits_gt0, bitmap_mask); row7_nbits_gt0 = vand_u8(row7_nbits_gt0, bitmap_mask); uint8x8_t bitmap_rows_10 = vpadd_u8(row1_nbits_gt0, row0_nbits_gt0); uint8x8_t bitmap_rows_32 = vpadd_u8(row3_nbits_gt0, row2_nbits_gt0); uint8x8_t bitmap_rows_54 = vpadd_u8(row5_nbits_gt0, row4_nbits_gt0); uint8x8_t bitmap_rows_76 = vpadd_u8(row7_nbits_gt0, row6_nbits_gt0); uint8x8_t bitmap_rows_3210 = vpadd_u8(bitmap_rows_32, bitmap_rows_10); uint8x8_t bitmap_rows_7654 = vpadd_u8(bitmap_rows_76, bitmap_rows_54); uint8x8_t bitmap = vpadd_u8(bitmap_rows_7654, bitmap_rows_3210); /* Shift left to remove DC bit. */ bitmap = vreinterpret_u8_u64(vshl_n_u64(vreinterpret_u64_u8(bitmap), 1)); /* Move bitmap to 32-bit scalar registers. */ uint32_t bitmap_1_32 = vget_lane_u32(vreinterpret_u32_u8(bitmap), 1); uint32_t bitmap_33_63 = vget_lane_u32(vreinterpret_u32_u8(bitmap), 0); /* Set up state and bit buffer for output bitstream. */ working_state *state_ptr = (working_state *)state; int free_bits = state_ptr->cur.free_bits; size_t put_buffer = state_ptr->cur.put_buffer; /* Encode DC coefficient. */ unsigned int nbits = block_nbits[0]; /* Emit Huffman-coded symbol and additional diff bits. */ unsigned int diff = block_diff[0]; PUT_CODE(dctbl->ehufco[nbits], dctbl->ehufsi[nbits], diff) /* Encode AC coefficients. */ unsigned int r = 0; /* r = run length of zeros */ unsigned int i = 1; /* i = number of coefficients encoded */ /* Code and size information for a run length of 16 zero coefficients */ const unsigned int code_0xf0 = actbl->ehufco[0xf0]; const unsigned int size_0xf0 = actbl->ehufsi[0xf0]; while (bitmap_1_32 != 0) { r = BUILTIN_CLZ(bitmap_1_32); i += r; bitmap_1_32 <<= r; nbits = block_nbits[i]; diff = block_diff[i]; while (r > 15) { /* If run length > 15, emit special run-length-16 codes. */ PUT_BITS(code_0xf0, size_0xf0) r -= 16; } /* Emit Huffman symbol for run length / number of bits. (F.1.2.2.1) */ unsigned int rs = (r << 4) + nbits; PUT_CODE(actbl->ehufco[rs], actbl->ehufsi[rs], diff) i++; bitmap_1_32 <<= 1; } r = 33 - i; i = 33; while (bitmap_33_63 != 0) { unsigned int leading_zeros = BUILTIN_CLZ(bitmap_33_63); r += leading_zeros; i += leading_zeros; bitmap_33_63 <<= leading_zeros; nbits = block_nbits[i]; diff = block_diff[i]; while (r > 15) { /* If run length > 15, emit special run-length-16 codes. */ PUT_BITS(code_0xf0, size_0xf0) r -= 16; } /* Emit Huffman symbol for run length / number of bits. (F.1.2.2.1) */ unsigned int rs = (r << 4) + nbits; PUT_CODE(actbl->ehufco[rs], actbl->ehufsi[rs], diff) r = 0; i++; bitmap_33_63 <<= 1; } /* If the last coefficient(s) were zero, emit an end-of-block (EOB) code. * The value of RS for the EOB code is 0. */ if (i != 64) { PUT_BITS(actbl->ehufco[0], actbl->ehufsi[0]) } state_ptr->cur.put_buffer = put_buffer; state_ptr->cur.free_bits = free_bits; return buffer; }