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https://github.com/libjpeg-turbo/libjpeg-turbo
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ea4ee22932
We use a standard set of strict compiler warnings with Clang and GCC to continuously test and maintain C89 conformance in the libjpeg API code. However, SIMD extensions need not comply with that. The Neon code specifically uses some C99isms, so disable -Wdeclaration-after-statement, -Wc99-extensions, and -Wpedantic in the scope of that code. Also modify the Neon feature tests so that they will succeed if any of the aforementioned compiler warnings are enabled.
217 lines
7.9 KiB
C
217 lines
7.9 KiB
C
/*
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* jfdctfst-neon.c - fast integer FDCT (Arm Neon)
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*
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* Copyright (C) 2020, Arm Limited. All Rights Reserved.
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* Copyright (C) 2024, D. R. Commander. All Rights Reserved.
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*
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* This software is provided 'as-is', without any express or implied
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* warranty. In no event will the authors be held liable for any damages
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* arising from the use of this software.
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*
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* Permission is granted to anyone to use this software for any purpose,
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* including commercial applications, and to alter it and redistribute it
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* freely, subject to the following restrictions:
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*
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* 1. The origin of this software must not be misrepresented; you must not
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* claim that you wrote the original software. If you use this software
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* in a product, an acknowledgment in the product documentation would be
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* appreciated but is not required.
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* 2. Altered source versions must be plainly marked as such, and must not be
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* misrepresented as being the original software.
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* 3. This notice may not be removed or altered from any source distribution.
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*/
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#define JPEG_INTERNALS
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#include "../../src/jinclude.h"
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#include "../../src/jpeglib.h"
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#include "../../src/jsimd.h"
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#include "../../src/jdct.h"
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#include "../../src/jsimddct.h"
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#include "../jsimd.h"
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#include "align.h"
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#include "neon-compat.h"
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#include <arm_neon.h>
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/* jsimd_fdct_ifast_neon() performs a fast, not so accurate forward DCT
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* (Discrete Cosine Transform) on one block of samples. It uses the same
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* calculations and produces exactly the same output as IJG's original
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* jpeg_fdct_ifast() function, which can be found in jfdctfst.c.
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*
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* Scaled integer constants are used to avoid floating-point arithmetic:
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* 0.382683433 = 12544 * 2^-15
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* 0.541196100 = 17795 * 2^-15
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* 0.707106781 = 23168 * 2^-15
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* 0.306562965 = 9984 * 2^-15
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*
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* See jfdctfst.c for further details of the DCT algorithm. Where possible,
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* the variable names and comments here in jsimd_fdct_ifast_neon() match up
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* with those in jpeg_fdct_ifast().
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*/
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#define F_0_382 12544
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#define F_0_541 17792
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#define F_0_707 23168
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#define F_0_306 9984
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ALIGN(16) static const int16_t jsimd_fdct_ifast_neon_consts[] = {
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F_0_382, F_0_541, F_0_707, F_0_306
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};
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void jsimd_fdct_ifast_neon(DCTELEM *data)
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{
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/* Load an 8x8 block of samples into Neon registers. De-interleaving loads
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* are used, followed by vuzp to transpose the block such that we have a
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* column of samples per vector - allowing all rows to be processed at once.
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*/
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int16x8x4_t data1 = vld4q_s16(data);
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int16x8x4_t data2 = vld4q_s16(data + 4 * DCTSIZE);
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int16x8x2_t cols_04 = vuzpq_s16(data1.val[0], data2.val[0]);
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int16x8x2_t cols_15 = vuzpq_s16(data1.val[1], data2.val[1]);
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int16x8x2_t cols_26 = vuzpq_s16(data1.val[2], data2.val[2]);
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int16x8x2_t cols_37 = vuzpq_s16(data1.val[3], data2.val[3]);
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int16x8_t col0 = cols_04.val[0];
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int16x8_t col1 = cols_15.val[0];
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int16x8_t col2 = cols_26.val[0];
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int16x8_t col3 = cols_37.val[0];
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int16x8_t col4 = cols_04.val[1];
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int16x8_t col5 = cols_15.val[1];
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int16x8_t col6 = cols_26.val[1];
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int16x8_t col7 = cols_37.val[1];
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/* Pass 1: process rows. */
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/* Load DCT conversion constants. */
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const int16x4_t consts = vld1_s16(jsimd_fdct_ifast_neon_consts);
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int16x8_t tmp0 = vaddq_s16(col0, col7);
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int16x8_t tmp7 = vsubq_s16(col0, col7);
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int16x8_t tmp1 = vaddq_s16(col1, col6);
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int16x8_t tmp6 = vsubq_s16(col1, col6);
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int16x8_t tmp2 = vaddq_s16(col2, col5);
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int16x8_t tmp5 = vsubq_s16(col2, col5);
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int16x8_t tmp3 = vaddq_s16(col3, col4);
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int16x8_t tmp4 = vsubq_s16(col3, col4);
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/* Even part */
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int16x8_t tmp10 = vaddq_s16(tmp0, tmp3); /* phase 2 */
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int16x8_t tmp13 = vsubq_s16(tmp0, tmp3);
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int16x8_t tmp11 = vaddq_s16(tmp1, tmp2);
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int16x8_t tmp12 = vsubq_s16(tmp1, tmp2);
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col0 = vaddq_s16(tmp10, tmp11); /* phase 3 */
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col4 = vsubq_s16(tmp10, tmp11);
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int16x8_t z1 = vqdmulhq_lane_s16(vaddq_s16(tmp12, tmp13), consts, 2);
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col2 = vaddq_s16(tmp13, z1); /* phase 5 */
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col6 = vsubq_s16(tmp13, z1);
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/* Odd part */
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tmp10 = vaddq_s16(tmp4, tmp5); /* phase 2 */
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tmp11 = vaddq_s16(tmp5, tmp6);
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tmp12 = vaddq_s16(tmp6, tmp7);
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int16x8_t z5 = vqdmulhq_lane_s16(vsubq_s16(tmp10, tmp12), consts, 0);
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int16x8_t z2 = vqdmulhq_lane_s16(tmp10, consts, 1);
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z2 = vaddq_s16(z2, z5);
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int16x8_t z4 = vqdmulhq_lane_s16(tmp12, consts, 3);
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z5 = vaddq_s16(tmp12, z5);
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z4 = vaddq_s16(z4, z5);
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int16x8_t z3 = vqdmulhq_lane_s16(tmp11, consts, 2);
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int16x8_t z11 = vaddq_s16(tmp7, z3); /* phase 5 */
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int16x8_t z13 = vsubq_s16(tmp7, z3);
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col5 = vaddq_s16(z13, z2); /* phase 6 */
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col3 = vsubq_s16(z13, z2);
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col1 = vaddq_s16(z11, z4);
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col7 = vsubq_s16(z11, z4);
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/* Transpose to work on columns in pass 2. */
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int16x8x2_t cols_01 = vtrnq_s16(col0, col1);
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int16x8x2_t cols_23 = vtrnq_s16(col2, col3);
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int16x8x2_t cols_45 = vtrnq_s16(col4, col5);
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int16x8x2_t cols_67 = vtrnq_s16(col6, col7);
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int32x4x2_t cols_0145_l = vtrnq_s32(vreinterpretq_s32_s16(cols_01.val[0]),
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vreinterpretq_s32_s16(cols_45.val[0]));
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int32x4x2_t cols_0145_h = vtrnq_s32(vreinterpretq_s32_s16(cols_01.val[1]),
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vreinterpretq_s32_s16(cols_45.val[1]));
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int32x4x2_t cols_2367_l = vtrnq_s32(vreinterpretq_s32_s16(cols_23.val[0]),
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vreinterpretq_s32_s16(cols_67.val[0]));
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int32x4x2_t cols_2367_h = vtrnq_s32(vreinterpretq_s32_s16(cols_23.val[1]),
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vreinterpretq_s32_s16(cols_67.val[1]));
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int32x4x2_t rows_04 = vzipq_s32(cols_0145_l.val[0], cols_2367_l.val[0]);
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int32x4x2_t rows_15 = vzipq_s32(cols_0145_h.val[0], cols_2367_h.val[0]);
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int32x4x2_t rows_26 = vzipq_s32(cols_0145_l.val[1], cols_2367_l.val[1]);
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int32x4x2_t rows_37 = vzipq_s32(cols_0145_h.val[1], cols_2367_h.val[1]);
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int16x8_t row0 = vreinterpretq_s16_s32(rows_04.val[0]);
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int16x8_t row1 = vreinterpretq_s16_s32(rows_15.val[0]);
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int16x8_t row2 = vreinterpretq_s16_s32(rows_26.val[0]);
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int16x8_t row3 = vreinterpretq_s16_s32(rows_37.val[0]);
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int16x8_t row4 = vreinterpretq_s16_s32(rows_04.val[1]);
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int16x8_t row5 = vreinterpretq_s16_s32(rows_15.val[1]);
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int16x8_t row6 = vreinterpretq_s16_s32(rows_26.val[1]);
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int16x8_t row7 = vreinterpretq_s16_s32(rows_37.val[1]);
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/* Pass 2: process columns. */
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tmp0 = vaddq_s16(row0, row7);
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tmp7 = vsubq_s16(row0, row7);
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tmp1 = vaddq_s16(row1, row6);
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tmp6 = vsubq_s16(row1, row6);
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tmp2 = vaddq_s16(row2, row5);
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tmp5 = vsubq_s16(row2, row5);
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tmp3 = vaddq_s16(row3, row4);
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tmp4 = vsubq_s16(row3, row4);
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/* Even part */
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tmp10 = vaddq_s16(tmp0, tmp3); /* phase 2 */
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tmp13 = vsubq_s16(tmp0, tmp3);
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tmp11 = vaddq_s16(tmp1, tmp2);
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tmp12 = vsubq_s16(tmp1, tmp2);
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row0 = vaddq_s16(tmp10, tmp11); /* phase 3 */
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row4 = vsubq_s16(tmp10, tmp11);
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z1 = vqdmulhq_lane_s16(vaddq_s16(tmp12, tmp13), consts, 2);
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row2 = vaddq_s16(tmp13, z1); /* phase 5 */
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row6 = vsubq_s16(tmp13, z1);
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/* Odd part */
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tmp10 = vaddq_s16(tmp4, tmp5); /* phase 2 */
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tmp11 = vaddq_s16(tmp5, tmp6);
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tmp12 = vaddq_s16(tmp6, tmp7);
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z5 = vqdmulhq_lane_s16(vsubq_s16(tmp10, tmp12), consts, 0);
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z2 = vqdmulhq_lane_s16(tmp10, consts, 1);
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z2 = vaddq_s16(z2, z5);
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z4 = vqdmulhq_lane_s16(tmp12, consts, 3);
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z5 = vaddq_s16(tmp12, z5);
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z4 = vaddq_s16(z4, z5);
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z3 = vqdmulhq_lane_s16(tmp11, consts, 2);
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z11 = vaddq_s16(tmp7, z3); /* phase 5 */
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z13 = vsubq_s16(tmp7, z3);
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row5 = vaddq_s16(z13, z2); /* phase 6 */
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row3 = vsubq_s16(z13, z2);
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row1 = vaddq_s16(z11, z4);
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row7 = vsubq_s16(z11, z4);
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vst1q_s16(data + 0 * DCTSIZE, row0);
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vst1q_s16(data + 1 * DCTSIZE, row1);
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vst1q_s16(data + 2 * DCTSIZE, row2);
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vst1q_s16(data + 3 * DCTSIZE, row3);
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vst1q_s16(data + 4 * DCTSIZE, row4);
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vst1q_s16(data + 5 * DCTSIZE, row5);
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vst1q_s16(data + 6 * DCTSIZE, row6);
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vst1q_s16(data + 7 * DCTSIZE, row7);
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}
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