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+/*
+ * ARM NEON optimizations for libjpeg-turbo
+ *
+ * Copyright (C) 2009-2011 Nokia Corporation and/or its subsidiary(-ies).
+ * All rights reserved.
+ * Author: Siarhei Siamashka <siarhei.siamashka@nokia.com>
+ *
+ * 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.
+ */
+
+#if defined(__linux__) && defined(__ELF__)
+.section .note.GNU-stack,"",%progbits /* mark stack as non-executable */
+#endif
+
+.text
+.fpu neon
+.arch armv7a
+.object_arch armv4
+.arm
+
+
+#define RESPECT_STRICT_ALIGNMENT 1
+
+/*****************************************************************************/
+
+/* Supplementary macro for setting function attributes */
+.macro asm_function fname
+#ifdef __APPLE__
+ .func _\fname
+ .globl _\fname
+_\fname:
+#else
+ .func \fname
+ .global \fname
+#ifdef __ELF__
+ .hidden \fname
+ .type \fname, %function
+#endif
+\fname:
+#endif
+.endm
+
+/* Transpose a block of 4x4 coefficients in four 64-bit registers */
+.macro transpose_4x4 x0, x1, x2, x3
+ vtrn.16 \x0, \x1
+ vtrn.16 \x2, \x3
+ vtrn.32 \x0, \x2
+ vtrn.32 \x1, \x3
+.endm
+
+#define CENTERJSAMPLE 128
+
+/*****************************************************************************/
+
+/*
+ * Perform dequantization and inverse DCT on one block of coefficients.
+ *
+ * GLOBAL(void)
+ * jsimd_idct_islow_neon (void * dct_table, JCOEFPTR coef_block,
+ * JSAMPARRAY output_buf, JDIMENSION output_col)
+ */
+
+#define FIX_0_298631336 (2446)
+#define FIX_0_390180644 (3196)
+#define FIX_0_541196100 (4433)
+#define FIX_0_765366865 (6270)
+#define FIX_0_899976223 (7373)
+#define FIX_1_175875602 (9633)
+#define FIX_1_501321110 (12299)
+#define FIX_1_847759065 (15137)
+#define FIX_1_961570560 (16069)
+#define FIX_2_053119869 (16819)
+#define FIX_2_562915447 (20995)
+#define FIX_3_072711026 (25172)
+
+#define FIX_1_175875602_MINUS_1_961570560 (FIX_1_175875602 - FIX_1_961570560)
+#define FIX_1_175875602_MINUS_0_390180644 (FIX_1_175875602 - FIX_0_390180644)
+#define FIX_0_541196100_MINUS_1_847759065 (FIX_0_541196100 - FIX_1_847759065)
+#define FIX_3_072711026_MINUS_2_562915447 (FIX_3_072711026 - FIX_2_562915447)
+#define FIX_0_298631336_MINUS_0_899976223 (FIX_0_298631336 - FIX_0_899976223)
+#define FIX_1_501321110_MINUS_0_899976223 (FIX_1_501321110 - FIX_0_899976223)
+#define FIX_2_053119869_MINUS_2_562915447 (FIX_2_053119869 - FIX_2_562915447)
+#define FIX_0_541196100_PLUS_0_765366865 (FIX_0_541196100 + FIX_0_765366865)
+
+/*
+ * Reference SIMD-friendly 1-D ISLOW iDCT C implementation.
+ * Uses some ideas from the comments in 'simd/jiss2int-64.asm'
+ */
+#define REF_1D_IDCT(xrow0, xrow1, xrow2, xrow3, xrow4, xrow5, xrow6, xrow7) \
+{ \
+ DCTELEM row0, row1, row2, row3, row4, row5, row6, row7; \
+ INT32 q1, q2, q3, q4, q5, q6, q7; \
+ INT32 tmp11_plus_tmp2, tmp11_minus_tmp2; \
+ \
+ /* 1-D iDCT input data */ \
+ row0 = xrow0; \
+ row1 = xrow1; \
+ row2 = xrow2; \
+ row3 = xrow3; \
+ row4 = xrow4; \
+ row5 = xrow5; \
+ row6 = xrow6; \
+ row7 = xrow7; \
+ \
+ q5 = row7 + row3; \
+ q4 = row5 + row1; \
+ q6 = MULTIPLY(q5, FIX_1_175875602_MINUS_1_961570560) + \
+ MULTIPLY(q4, FIX_1_175875602); \
+ q7 = MULTIPLY(q5, FIX_1_175875602) + \
+ MULTIPLY(q4, FIX_1_175875602_MINUS_0_390180644); \
+ q2 = MULTIPLY(row2, FIX_0_541196100) + \
+ MULTIPLY(row6, FIX_0_541196100_MINUS_1_847759065); \
+ q4 = q6; \
+ q3 = ((INT32) row0 - (INT32) row4) << 13; \
+ q6 += MULTIPLY(row5, -FIX_2_562915447) + \
+ MULTIPLY(row3, FIX_3_072711026_MINUS_2_562915447); \
+ /* now we can use q1 (reloadable constants have been used up) */ \
+ q1 = q3 + q2; \
+ q4 += MULTIPLY(row7, FIX_0_298631336_MINUS_0_899976223) + \
+ MULTIPLY(row1, -FIX_0_899976223); \
+ q5 = q7; \
+ q1 = q1 + q6; \
+ q7 += MULTIPLY(row7, -FIX_0_899976223) + \
+ MULTIPLY(row1, FIX_1_501321110_MINUS_0_899976223); \
+ \
+ /* (tmp11 + tmp2) has been calculated (out_row1 before descale) */ \
+ tmp11_plus_tmp2 = q1; \
+ row1 = 0; \
+ \
+ q1 = q1 - q6; \
+ q5 += MULTIPLY(row5, FIX_2_053119869_MINUS_2_562915447) + \
+ MULTIPLY(row3, -FIX_2_562915447); \
+ q1 = q1 - q6; \
+ q6 = MULTIPLY(row2, FIX_0_541196100_PLUS_0_765366865) + \
+ MULTIPLY(row6, FIX_0_541196100); \
+ q3 = q3 - q2; \
+ \
+ /* (tmp11 - tmp2) has been calculated (out_row6 before descale) */ \
+ tmp11_minus_tmp2 = q1; \
+ \
+ q1 = ((INT32) row0 + (INT32) row4) << 13; \
+ q2 = q1 + q6; \
+ q1 = q1 - q6; \
+ \
+ /* pick up the results */ \
+ tmp0 = q4; \
+ tmp1 = q5; \
+ tmp2 = (tmp11_plus_tmp2 - tmp11_minus_tmp2) / 2; \
+ tmp3 = q7; \
+ tmp10 = q2; \
+ tmp11 = (tmp11_plus_tmp2 + tmp11_minus_tmp2) / 2; \
+ tmp12 = q3; \
+ tmp13 = q1; \
+}
+
+#define XFIX_0_899976223 d0[0]
+#define XFIX_0_541196100 d0[1]
+#define XFIX_2_562915447 d0[2]
+#define XFIX_0_298631336_MINUS_0_899976223 d0[3]
+#define XFIX_1_501321110_MINUS_0_899976223 d1[0]
+#define XFIX_2_053119869_MINUS_2_562915447 d1[1]
+#define XFIX_0_541196100_PLUS_0_765366865 d1[2]
+#define XFIX_1_175875602 d1[3]
+#define XFIX_1_175875602_MINUS_0_390180644 d2[0]
+#define XFIX_0_541196100_MINUS_1_847759065 d2[1]
+#define XFIX_3_072711026_MINUS_2_562915447 d2[2]
+#define XFIX_1_175875602_MINUS_1_961570560 d2[3]
+
+.balign 16
+jsimd_idct_islow_neon_consts:
+ .short FIX_0_899976223 /* d0[0] */
+ .short FIX_0_541196100 /* d0[1] */
+ .short FIX_2_562915447 /* d0[2] */
+ .short FIX_0_298631336_MINUS_0_899976223 /* d0[3] */
+ .short FIX_1_501321110_MINUS_0_899976223 /* d1[0] */
+ .short FIX_2_053119869_MINUS_2_562915447 /* d1[1] */
+ .short FIX_0_541196100_PLUS_0_765366865 /* d1[2] */
+ .short FIX_1_175875602 /* d1[3] */
+ /* reloadable constants */
+ .short FIX_1_175875602_MINUS_0_390180644 /* d2[0] */
+ .short FIX_0_541196100_MINUS_1_847759065 /* d2[1] */
+ .short FIX_3_072711026_MINUS_2_562915447 /* d2[2] */
+ .short FIX_1_175875602_MINUS_1_961570560 /* d2[3] */
+
+asm_function jsimd_idct_islow_neon
+
+ DCT_TABLE .req r0
+ COEF_BLOCK .req r1
+ OUTPUT_BUF .req r2
+ OUTPUT_COL .req r3
+ TMP1 .req r0
+ TMP2 .req r1
+ TMP3 .req r2
+ TMP4 .req ip
+
+ ROW0L .req d16
+ ROW0R .req d17
+ ROW1L .req d18
+ ROW1R .req d19
+ ROW2L .req d20
+ ROW2R .req d21
+ ROW3L .req d22
+ ROW3R .req d23
+ ROW4L .req d24
+ ROW4R .req d25
+ ROW5L .req d26
+ ROW5R .req d27
+ ROW6L .req d28
+ ROW6R .req d29
+ ROW7L .req d30
+ ROW7R .req d31
+
+ /* Load and dequantize coefficients into NEON registers
+ * with the following allocation:
+ * 0 1 2 3 | 4 5 6 7
+ * ---------+--------
+ * 0 | d16 | d17 ( q8 )
+ * 1 | d18 | d19 ( q9 )
+ * 2 | d20 | d21 ( q10 )
+ * 3 | d22 | d23 ( q11 )
+ * 4 | d24 | d25 ( q12 )
+ * 5 | d26 | d27 ( q13 )
+ * 6 | d28 | d29 ( q14 )
+ * 7 | d30 | d31 ( q15 )
+ */
+ adr ip, jsimd_idct_islow_neon_consts
+ vld1.16 {d16, d17, d18, d19}, [COEF_BLOCK, :128]!
+ vld1.16 {d0, d1, d2, d3}, [DCT_TABLE, :128]!
+ vld1.16 {d20, d21, d22, d23}, [COEF_BLOCK, :128]!
+ vmul.s16 q8, q8, q0
+ vld1.16 {d4, d5, d6, d7}, [DCT_TABLE, :128]!
+ vmul.s16 q9, q9, q1
+ vld1.16 {d24, d25, d26, d27}, [COEF_BLOCK, :128]!
+ vmul.s16 q10, q10, q2
+ vld1.16 {d0, d1, d2, d3}, [DCT_TABLE, :128]!
+ vmul.s16 q11, q11, q3
+ vld1.16 {d28, d29, d30, d31}, [COEF_BLOCK, :128]
+ vmul.s16 q12, q12, q0
+ vld1.16 {d4, d5, d6, d7}, [DCT_TABLE, :128]!
+ vmul.s16 q14, q14, q2
+ vmul.s16 q13, q13, q1
+ vld1.16 {d0, d1, d2, d3}, [ip, :128] /* load constants */
+ add ip, ip, #16
+ vmul.s16 q15, q15, q3
+ vpush {d8-d15} /* save NEON registers */
+ /* 1-D IDCT, pass 1, left 4x8 half */
+ vadd.s16 d4, ROW7L, ROW3L
+ vadd.s16 d5, ROW5L, ROW1L
+ vmull.s16 q6, d4, XFIX_1_175875602_MINUS_1_961570560
+ vmlal.s16 q6, d5, XFIX_1_175875602
+ vmull.s16 q7, d4, XFIX_1_175875602
+ /* Check for the zero coefficients in the right 4x8 half */
+ push {r4, r5}
+ vmlal.s16 q7, d5, XFIX_1_175875602_MINUS_0_390180644
+ vsubl.s16 q3, ROW0L, ROW4L
+ ldrd r4, [COEF_BLOCK, #(-96 + 2 * (4 + 1 * 8))]
+ vmull.s16 q2, ROW2L, XFIX_0_541196100
+ vmlal.s16 q2, ROW6L, XFIX_0_541196100_MINUS_1_847759065
+ orr r0, r4, r5
+ vmov q4, q6
+ vmlsl.s16 q6, ROW5L, XFIX_2_562915447
+ ldrd r4, [COEF_BLOCK, #(-96 + 2 * (4 + 2 * 8))]
+ vmlal.s16 q6, ROW3L, XFIX_3_072711026_MINUS_2_562915447
+ vshl.s32 q3, q3, #13
+ orr r0, r0, r4
+ vmlsl.s16 q4, ROW1L, XFIX_0_899976223
+ orr r0, r0, r5
+ vadd.s32 q1, q3, q2
+ ldrd r4, [COEF_BLOCK, #(-96 + 2 * (4 + 3 * 8))]
+ vmov q5, q7
+ vadd.s32 q1, q1, q6
+ orr r0, r0, r4
+ vmlsl.s16 q7, ROW7L, XFIX_0_899976223
+ orr r0, r0, r5
+ vmlal.s16 q7, ROW1L, XFIX_1_501321110_MINUS_0_899976223
+ vrshrn.s32 ROW1L, q1, #11
+ ldrd r4, [COEF_BLOCK, #(-96 + 2 * (4 + 4 * 8))]
+ vsub.s32 q1, q1, q6
+ vmlal.s16 q5, ROW5L, XFIX_2_053119869_MINUS_2_562915447
+ orr r0, r0, r4
+ vmlsl.s16 q5, ROW3L, XFIX_2_562915447
+ orr r0, r0, r5
+ vsub.s32 q1, q1, q6
+ vmull.s16 q6, ROW2L, XFIX_0_541196100_PLUS_0_765366865
+ ldrd r4, [COEF_BLOCK, #(-96 + 2 * (4 + 5 * 8))]
+ vmlal.s16 q6, ROW6L, XFIX_0_541196100
+ vsub.s32 q3, q3, q2
+ orr r0, r0, r4
+ vrshrn.s32 ROW6L, q1, #11
+ orr r0, r0, r5
+ vadd.s32 q1, q3, q5
+ ldrd r4, [COEF_BLOCK, #(-96 + 2 * (4 + 6 * 8))]
+ vsub.s32 q3, q3, q5
+ vaddl.s16 q5, ROW0L, ROW4L
+ orr r0, r0, r4
+ vrshrn.s32 ROW2L, q1, #11
+ orr r0, r0, r5
+ vrshrn.s32 ROW5L, q3, #11
+ ldrd r4, [COEF_BLOCK, #(-96 + 2 * (4 + 7 * 8))]
+ vshl.s32 q5, q5, #13
+ vmlal.s16 q4, ROW7L, XFIX_0_298631336_MINUS_0_899976223
+ orr r0, r0, r4
+ vadd.s32 q2, q5, q6
+ orrs r0, r0, r5
+ vsub.s32 q1, q5, q6
+ vadd.s32 q6, q2, q7
+ ldrd r4, [COEF_BLOCK, #(-96 + 2 * (4 + 0 * 8))]
+ vsub.s32 q2, q2, q7
+ vadd.s32 q5, q1, q4
+ orr r0, r4, r5
+ vsub.s32 q3, q1, q4
+ pop {r4, r5}
+ vrshrn.s32 ROW7L, q2, #11
+ vrshrn.s32 ROW3L, q5, #11
+ vrshrn.s32 ROW0L, q6, #11
+ vrshrn.s32 ROW4L, q3, #11
+
+ beq 3f /* Go to do some special handling for the sparse right 4x8 half */
+
+ /* 1-D IDCT, pass 1, right 4x8 half */
+ vld1.s16 {d2}, [ip, :64] /* reload constants */
+ vadd.s16 d10, ROW7R, ROW3R
+ vadd.s16 d8, ROW5R, ROW1R
+ /* Transpose left 4x8 half */
+ vtrn.16 ROW6L, ROW7L
+ vmull.s16 q6, d10, XFIX_1_175875602_MINUS_1_961570560
+ vmlal.s16 q6, d8, XFIX_1_175875602
+ vtrn.16 ROW2L, ROW3L
+ vmull.s16 q7, d10, XFIX_1_175875602
+ vmlal.s16 q7, d8, XFIX_1_175875602_MINUS_0_390180644
+ vtrn.16 ROW0L, ROW1L
+ vsubl.s16 q3, ROW0R, ROW4R
+ vmull.s16 q2, ROW2R, XFIX_0_541196100
+ vmlal.s16 q2, ROW6R, XFIX_0_541196100_MINUS_1_847759065
+ vtrn.16 ROW4L, ROW5L
+ vmov q4, q6
+ vmlsl.s16 q6, ROW5R, XFIX_2_562915447
+ vmlal.s16 q6, ROW3R, XFIX_3_072711026_MINUS_2_562915447
+ vtrn.32 ROW1L, ROW3L
+ vshl.s32 q3, q3, #13
+ vmlsl.s16 q4, ROW1R, XFIX_0_899976223
+ vtrn.32 ROW4L, ROW6L
+ vadd.s32 q1, q3, q2
+ vmov q5, q7
+ vadd.s32 q1, q1, q6
+ vtrn.32 ROW0L, ROW2L
+ vmlsl.s16 q7, ROW7R, XFIX_0_899976223
+ vmlal.s16 q7, ROW1R, XFIX_1_501321110_MINUS_0_899976223
+ vrshrn.s32 ROW1R, q1, #11
+ vtrn.32 ROW5L, ROW7L
+ vsub.s32 q1, q1, q6
+ vmlal.s16 q5, ROW5R, XFIX_2_053119869_MINUS_2_562915447
+ vmlsl.s16 q5, ROW3R, XFIX_2_562915447
+ vsub.s32 q1, q1, q6
+ vmull.s16 q6, ROW2R, XFIX_0_541196100_PLUS_0_765366865
+ vmlal.s16 q6, ROW6R, XFIX_0_541196100
+ vsub.s32 q3, q3, q2
+ vrshrn.s32 ROW6R, q1, #11
+ vadd.s32 q1, q3, q5
+ vsub.s32 q3, q3, q5
+ vaddl.s16 q5, ROW0R, ROW4R
+ vrshrn.s32 ROW2R, q1, #11
+ vrshrn.s32 ROW5R, q3, #11
+ vshl.s32 q5, q5, #13
+ vmlal.s16 q4, ROW7R, XFIX_0_298631336_MINUS_0_899976223
+ vadd.s32 q2, q5, q6
+ vsub.s32 q1, q5, q6
+ vadd.s32 q6, q2, q7
+ vsub.s32 q2, q2, q7
+ vadd.s32 q5, q1, q4
+ vsub.s32 q3, q1, q4
+ vrshrn.s32 ROW7R, q2, #11
+ vrshrn.s32 ROW3R, q5, #11
+ vrshrn.s32 ROW0R, q6, #11
+ vrshrn.s32 ROW4R, q3, #11
+ /* Transpose right 4x8 half */
+ vtrn.16 ROW6R, ROW7R
+ vtrn.16 ROW2R, ROW3R
+ vtrn.16 ROW0R, ROW1R
+ vtrn.16 ROW4R, ROW5R
+ vtrn.32 ROW1R, ROW3R
+ vtrn.32 ROW4R, ROW6R
+ vtrn.32 ROW0R, ROW2R
+ vtrn.32 ROW5R, ROW7R
+
+1: /* 1-D IDCT, pass 2 (normal variant), left 4x8 half */
+ vld1.s16 {d2}, [ip, :64] /* reload constants */
+ vmull.s16 q6, ROW1R, XFIX_1_175875602 /* ROW5L <-> ROW1R */
+ vmlal.s16 q6, ROW1L, XFIX_1_175875602
+ vmlal.s16 q6, ROW3R, XFIX_1_175875602_MINUS_1_961570560 /* ROW7L <-> ROW3R */
+ vmlal.s16 q6, ROW3L, XFIX_1_175875602_MINUS_1_961570560
+ vmull.s16 q7, ROW3R, XFIX_1_175875602 /* ROW7L <-> ROW3R */
+ vmlal.s16 q7, ROW3L, XFIX_1_175875602
+ vmlal.s16 q7, ROW1R, XFIX_1_175875602_MINUS_0_390180644 /* ROW5L <-> ROW1R */
+ vmlal.s16 q7, ROW1L, XFIX_1_175875602_MINUS_0_390180644
+ vsubl.s16 q3, ROW0L, ROW0R /* ROW4L <-> ROW0R */
+ vmull.s16 q2, ROW2L, XFIX_0_541196100
+ vmlal.s16 q2, ROW2R, XFIX_0_541196100_MINUS_1_847759065 /* ROW6L <-> ROW2R */
+ vmov q4, q6
+ vmlsl.s16 q6, ROW1R, XFIX_2_562915447 /* ROW5L <-> ROW1R */
+ vmlal.s16 q6, ROW3L, XFIX_3_072711026_MINUS_2_562915447
+ vshl.s32 q3, q3, #13
+ vmlsl.s16 q4, ROW1L, XFIX_0_899976223
+ vadd.s32 q1, q3, q2
+ vmov q5, q7
+ vadd.s32 q1, q1, q6
+ vmlsl.s16 q7, ROW3R, XFIX_0_899976223 /* ROW7L <-> ROW3R */
+ vmlal.s16 q7, ROW1L, XFIX_1_501321110_MINUS_0_899976223
+ vshrn.s32 ROW1L, q1, #16
+ vsub.s32 q1, q1, q6
+ vmlal.s16 q5, ROW1R, XFIX_2_053119869_MINUS_2_562915447 /* ROW5L <-> ROW1R */
+ vmlsl.s16 q5, ROW3L, XFIX_2_562915447
+ vsub.s32 q1, q1, q6
+ vmull.s16 q6, ROW2L, XFIX_0_541196100_PLUS_0_765366865
+ vmlal.s16 q6, ROW2R, XFIX_0_541196100 /* ROW6L <-> ROW2R */
+ vsub.s32 q3, q3, q2
+ vshrn.s32 ROW2R, q1, #16 /* ROW6L <-> ROW2R */
+ vadd.s32 q1, q3, q5
+ vsub.s32 q3, q3, q5
+ vaddl.s16 q5, ROW0L, ROW0R /* ROW4L <-> ROW0R */
+ vshrn.s32 ROW2L, q1, #16
+ vshrn.s32 ROW1R, q3, #16 /* ROW5L <-> ROW1R */
+ vshl.s32 q5, q5, #13
+ vmlal.s16 q4, ROW3R, XFIX_0_298631336_MINUS_0_899976223 /* ROW7L <-> ROW3R */
+ vadd.s32 q2, q5, q6
+ vsub.s32 q1, q5, q6
+ vadd.s32 q6, q2, q7
+ vsub.s32 q2, q2, q7
+ vadd.s32 q5, q1, q4
+ vsub.s32 q3, q1, q4
+ vshrn.s32 ROW3R, q2, #16 /* ROW7L <-> ROW3R */
+ vshrn.s32 ROW3L, q5, #16
+ vshrn.s32 ROW0L, q6, #16
+ vshrn.s32 ROW0R, q3, #16 /* ROW4L <-> ROW0R */
+ /* 1-D IDCT, pass 2, right 4x8 half */
+ vld1.s16 {d2}, [ip, :64] /* reload constants */
+ vmull.s16 q6, ROW5R, XFIX_1_175875602
+ vmlal.s16 q6, ROW5L, XFIX_1_175875602 /* ROW5L <-> ROW1R */
+ vmlal.s16 q6, ROW7R, XFIX_1_175875602_MINUS_1_961570560
+ vmlal.s16 q6, ROW7L, XFIX_1_175875602_MINUS_1_961570560 /* ROW7L <-> ROW3R */
+ vmull.s16 q7, ROW7R, XFIX_1_175875602
+ vmlal.s16 q7, ROW7L, XFIX_1_175875602 /* ROW7L <-> ROW3R */
+ vmlal.s16 q7, ROW5R, XFIX_1_175875602_MINUS_0_390180644
+ vmlal.s16 q7, ROW5L, XFIX_1_175875602_MINUS_0_390180644 /* ROW5L <-> ROW1R */
+ vsubl.s16 q3, ROW4L, ROW4R /* ROW4L <-> ROW0R */
+ vmull.s16 q2, ROW6L, XFIX_0_541196100 /* ROW6L <-> ROW2R */
+ vmlal.s16 q2, ROW6R, XFIX_0_541196100_MINUS_1_847759065
+ vmov q4, q6
+ vmlsl.s16 q6, ROW5R, XFIX_2_562915447
+ vmlal.s16 q6, ROW7L, XFIX_3_072711026_MINUS_2_562915447 /* ROW7L <-> ROW3R */
+ vshl.s32 q3, q3, #13
+ vmlsl.s16 q4, ROW5L, XFIX_0_899976223 /* ROW5L <-> ROW1R */
+ vadd.s32 q1, q3, q2
+ vmov q5, q7
+ vadd.s32 q1, q1, q6
+ vmlsl.s16 q7, ROW7R, XFIX_0_899976223
+ vmlal.s16 q7, ROW5L, XFIX_1_501321110_MINUS_0_899976223 /* ROW5L <-> ROW1R */
+ vshrn.s32 ROW5L, q1, #16 /* ROW5L <-> ROW1R */
+ vsub.s32 q1, q1, q6
+ vmlal.s16 q5, ROW5R, XFIX_2_053119869_MINUS_2_562915447
+ vmlsl.s16 q5, ROW7L, XFIX_2_562915447 /* ROW7L <-> ROW3R */
+ vsub.s32 q1, q1, q6
+ vmull.s16 q6, ROW6L, XFIX_0_541196100_PLUS_0_765366865 /* ROW6L <-> ROW2R */
+ vmlal.s16 q6, ROW6R, XFIX_0_541196100
+ vsub.s32 q3, q3, q2
+ vshrn.s32 ROW6R, q1, #16
+ vadd.s32 q1, q3, q5
+ vsub.s32 q3, q3, q5
+ vaddl.s16 q5, ROW4L, ROW4R /* ROW4L <-> ROW0R */
+ vshrn.s32 ROW6L, q1, #16 /* ROW6L <-> ROW2R */
+ vshrn.s32 ROW5R, q3, #16
+ vshl.s32 q5, q5, #13
+ vmlal.s16 q4, ROW7R, XFIX_0_298631336_MINUS_0_899976223
+ vadd.s32 q2, q5, q6
+ vsub.s32 q1, q5, q6
+ vadd.s32 q6, q2, q7
+ vsub.s32 q2, q2, q7
+ vadd.s32 q5, q1, q4
+ vsub.s32 q3, q1, q4
+ vshrn.s32 ROW7R, q2, #16
+ vshrn.s32 ROW7L, q5, #16 /* ROW7L <-> ROW3R */
+ vshrn.s32 ROW4L, q6, #16 /* ROW4L <-> ROW0R */
+ vshrn.s32 ROW4R, q3, #16
+
+2: /* Descale to 8-bit and range limit */
+ vqrshrn.s16 d16, q8, #2
+ vqrshrn.s16 d17, q9, #2
+ vqrshrn.s16 d18, q10, #2
+ vqrshrn.s16 d19, q11, #2
+ vpop {d8-d15} /* restore NEON registers */
+ vqrshrn.s16 d20, q12, #2
+ /* Transpose the final 8-bit samples and do signed->unsigned conversion */
+ vtrn.16 q8, q9
+ vqrshrn.s16 d21, q13, #2
+ vqrshrn.s16 d22, q14, #2
+ vmov.u8 q0, #(CENTERJSAMPLE)
+ vqrshrn.s16 d23, q15, #2
+ vtrn.8 d16, d17
+ vtrn.8 d18, d19
+ vadd.u8 q8, q8, q0
+ vadd.u8 q9, q9, q0
+ vtrn.16 q10, q11
+ /* Store results to the output buffer */
+ ldmia OUTPUT_BUF!, {TMP1, TMP2}
+ add TMP1, TMP1, OUTPUT_COL
+ add TMP2, TMP2, OUTPUT_COL
+ vst1.8 {d16}, [TMP1]
+ vtrn.8 d20, d21
+ vst1.8 {d17}, [TMP2]
+ ldmia OUTPUT_BUF!, {TMP1, TMP2}
+ add TMP1, TMP1, OUTPUT_COL
+ add TMP2, TMP2, OUTPUT_COL
+ vst1.8 {d18}, [TMP1]
+ vadd.u8 q10, q10, q0
+ vst1.8 {d19}, [TMP2]
+ ldmia OUTPUT_BUF, {TMP1, TMP2, TMP3, TMP4}
+ add TMP1, TMP1, OUTPUT_COL
+ add TMP2, TMP2, OUTPUT_COL
+ add TMP3, TMP3, OUTPUT_COL
+ add TMP4, TMP4, OUTPUT_COL
+ vtrn.8 d22, d23
+ vst1.8 {d20}, [TMP1]
+ vadd.u8 q11, q11, q0
+ vst1.8 {d21}, [TMP2]
+ vst1.8 {d22}, [TMP3]
+ vst1.8 {d23}, [TMP4]
+ bx lr
+
+3: /* Left 4x8 half is done, right 4x8 half contains mostly zeros */
+
+ /* Transpose left 4x8 half */
+ vtrn.16 ROW6L, ROW7L
+ vtrn.16 ROW2L, ROW3L
+ vtrn.16 ROW0L, ROW1L
+ vtrn.16 ROW4L, ROW5L
+ vshl.s16 ROW0R, ROW0R, #2 /* PASS1_BITS */
+ vtrn.32 ROW1L, ROW3L
+ vtrn.32 ROW4L, ROW6L
+ vtrn.32 ROW0L, ROW2L
+ vtrn.32 ROW5L, ROW7L
+
+ cmp r0, #0
+ beq 4f /* Right 4x8 half has all zeros, go to 'sparse' second pass */
+
+ /* Only row 0 is non-zero for the right 4x8 half */
+ vdup.s16 ROW1R, ROW0R[1]
+ vdup.s16 ROW2R, ROW0R[2]
+ vdup.s16 ROW3R, ROW0R[3]
+ vdup.s16 ROW4R, ROW0R[0]
+ vdup.s16 ROW5R, ROW0R[1]
+ vdup.s16 ROW6R, ROW0R[2]
+ vdup.s16 ROW7R, ROW0R[3]
+ vdup.s16 ROW0R, ROW0R[0]
+ b 1b /* Go to 'normal' second pass */
+
+4: /* 1-D IDCT, pass 2 (sparse variant with zero rows 4-7), left 4x8 half */
+ vld1.s16 {d2}, [ip, :64] /* reload constants */
+ vmull.s16 q6, ROW1L, XFIX_1_175875602
+ vmlal.s16 q6, ROW3L, XFIX_1_175875602_MINUS_1_961570560
+ vmull.s16 q7, ROW3L, XFIX_1_175875602
+ vmlal.s16 q7, ROW1L, XFIX_1_175875602_MINUS_0_390180644
+ vmull.s16 q2, ROW2L, XFIX_0_541196100
+ vshll.s16 q3, ROW0L, #13
+ vmov q4, q6
+ vmlal.s16 q6, ROW3L, XFIX_3_072711026_MINUS_2_562915447
+ vmlsl.s16 q4, ROW1L, XFIX_0_899976223
+ vadd.s32 q1, q3, q2
+ vmov q5, q7
+ vmlal.s16 q7, ROW1L, XFIX_1_501321110_MINUS_0_899976223
+ vadd.s32 q1, q1, q6
+ vadd.s32 q6, q6, q6
+ vmlsl.s16 q5, ROW3L, XFIX_2_562915447
+ vshrn.s32 ROW1L, q1, #16
+ vsub.s32 q1, q1, q6
+ vmull.s16 q6, ROW2L, XFIX_0_541196100_PLUS_0_765366865
+ vsub.s32 q3, q3, q2
+ vshrn.s32 ROW2R, q1, #16 /* ROW6L <-> ROW2R */
+ vadd.s32 q1, q3, q5
+ vsub.s32 q3, q3, q5
+ vshll.s16 q5, ROW0L, #13
+ vshrn.s32 ROW2L, q1, #16
+ vshrn.s32 ROW1R, q3, #16 /* ROW5L <-> ROW1R */
+ vadd.s32 q2, q5, q6
+ vsub.s32 q1, q5, q6
+ vadd.s32 q6, q2, q7
+ vsub.s32 q2, q2, q7
+ vadd.s32 q5, q1, q4
+ vsub.s32 q3, q1, q4
+ vshrn.s32 ROW3R, q2, #16 /* ROW7L <-> ROW3R */
+ vshrn.s32 ROW3L, q5, #16
+ vshrn.s32 ROW0L, q6, #16
+ vshrn.s32 ROW0R, q3, #16 /* ROW4L <-> ROW0R */
+ /* 1-D IDCT, pass 2 (sparse variant with zero rows 4-7), right 4x8 half */
+ vld1.s16 {d2}, [ip, :64] /* reload constants */
+ vmull.s16 q6, ROW5L, XFIX_1_175875602
+ vmlal.s16 q6, ROW7L, XFIX_1_175875602_MINUS_1_961570560
+ vmull.s16 q7, ROW7L, XFIX_1_175875602
+ vmlal.s16 q7, ROW5L, XFIX_1_175875602_MINUS_0_390180644
+ vmull.s16 q2, ROW6L, XFIX_0_541196100
+ vshll.s16 q3, ROW4L, #13
+ vmov q4, q6
+ vmlal.s16 q6, ROW7L, XFIX_3_072711026_MINUS_2_562915447
+ vmlsl.s16 q4, ROW5L, XFIX_0_899976223
+ vadd.s32 q1, q3, q2
+ vmov q5, q7
+ vmlal.s16 q7, ROW5L, XFIX_1_501321110_MINUS_0_899976223
+ vadd.s32 q1, q1, q6
+ vadd.s32 q6, q6, q6
+ vmlsl.s16 q5, ROW7L, XFIX_2_562915447
+ vshrn.s32 ROW5L, q1, #16 /* ROW5L <-> ROW1R */
+ vsub.s32 q1, q1, q6
+ vmull.s16 q6, ROW6L, XFIX_0_541196100_PLUS_0_765366865
+ vsub.s32 q3, q3, q2
+ vshrn.s32 ROW6R, q1, #16
+ vadd.s32 q1, q3, q5
+ vsub.s32 q3, q3, q5
+ vshll.s16 q5, ROW4L, #13
+ vshrn.s32 ROW6L, q1, #16 /* ROW6L <-> ROW2R */
+ vshrn.s32 ROW5R, q3, #16
+ vadd.s32 q2, q5, q6
+ vsub.s32 q1, q5, q6
+ vadd.s32 q6, q2, q7
+ vsub.s32 q2, q2, q7
+ vadd.s32 q5, q1, q4
+ vsub.s32 q3, q1, q4
+ vshrn.s32 ROW7R, q2, #16
+ vshrn.s32 ROW7L, q5, #16 /* ROW7L <-> ROW3R */
+ vshrn.s32 ROW4L, q6, #16 /* ROW4L <-> ROW0R */
+ vshrn.s32 ROW4R, q3, #16
+ b 2b /* Go to epilogue */
+
+ .unreq DCT_TABLE
+ .unreq COEF_BLOCK
+ .unreq OUTPUT_BUF
+ .unreq OUTPUT_COL
+ .unreq TMP1
+ .unreq TMP2
+ .unreq TMP3
+ .unreq TMP4
+
+ .unreq ROW0L
+ .unreq ROW0R
+ .unreq ROW1L
+ .unreq ROW1R
+ .unreq ROW2L
+ .unreq ROW2R
+ .unreq ROW3L
+ .unreq ROW3R
+ .unreq ROW4L
+ .unreq ROW4R
+ .unreq ROW5L
+ .unreq ROW5R
+ .unreq ROW6L
+ .unreq ROW6R
+ .unreq ROW7L
+ .unreq ROW7R
+.endfunc
+
+/*****************************************************************************/
+
+/*
+ * jsimd_idct_ifast_neon
+ *
+ * This function contains a fast, not so accurate integer implementation of
+ * the inverse DCT (Discrete Cosine Transform). It uses the same calculations
+ * and produces exactly the same output as IJG's original 'jpeg_idct_ifast'
+ * function from jidctfst.c
+ *
+ * Normally 1-D AAN DCT needs 5 multiplications and 29 additions.
+ * But in ARM NEON case some extra additions are required because VQDMULH
+ * instruction can't handle the constants larger than 1. So the expressions
+ * like "x * 1.082392200" have to be converted to "x * 0.082392200 + x",
+ * which introduces an extra addition. Overall, there are 6 extra additions
+ * per 1-D IDCT pass, totalling to 5 VQDMULH and 35 VADD/VSUB instructions.
+ */
+
+#define XFIX_1_082392200 d0[0]
+#define XFIX_1_414213562 d0[1]
+#define XFIX_1_847759065 d0[2]
+#define XFIX_2_613125930 d0[3]
+
+.balign 16
+jsimd_idct_ifast_neon_consts:
+ .short (277 * 128 - 256 * 128) /* XFIX_1_082392200 */
+ .short (362 * 128 - 256 * 128) /* XFIX_1_414213562 */
+ .short (473 * 128 - 256 * 128) /* XFIX_1_847759065 */
+ .short (669 * 128 - 512 * 128) /* XFIX_2_613125930 */
+
+asm_function jsimd_idct_ifast_neon
+
+ DCT_TABLE .req r0
+ COEF_BLOCK .req r1
+ OUTPUT_BUF .req r2
+ OUTPUT_COL .req r3
+ TMP1 .req r0
+ TMP2 .req r1
+ TMP3 .req r2
+ TMP4 .req ip
+
+ /* Load and dequantize coefficients into NEON registers
+ * with the following allocation:
+ * 0 1 2 3 | 4 5 6 7
+ * ---------+--------
+ * 0 | d16 | d17 ( q8 )
+ * 1 | d18 | d19 ( q9 )
+ * 2 | d20 | d21 ( q10 )
+ * 3 | d22 | d23 ( q11 )
+ * 4 | d24 | d25 ( q12 )
+ * 5 | d26 | d27 ( q13 )
+ * 6 | d28 | d29 ( q14 )
+ * 7 | d30 | d31 ( q15 )
+ */
+ adr ip, jsimd_idct_ifast_neon_consts
+ vld1.16 {d16, d17, d18, d19}, [COEF_BLOCK, :128]!
+ vld1.16 {d0, d1, d2, d3}, [DCT_TABLE, :128]!
+ vld1.16 {d20, d21, d22, d23}, [COEF_BLOCK, :128]!
+ vmul.s16 q8, q8, q0
+ vld1.16 {d4, d5, d6, d7}, [DCT_TABLE, :128]!
+ vmul.s16 q9, q9, q1
+ vld1.16 {d24, d25, d26, d27}, [COEF_BLOCK, :128]!
+ vmul.s16 q10, q10, q2
+ vld1.16 {d0, d1, d2, d3}, [DCT_TABLE, :128]!
+ vmul.s16 q11, q11, q3
+ vld1.16 {d28, d29, d30, d31}, [COEF_BLOCK, :128]
+ vmul.s16 q12, q12, q0
+ vld1.16 {d4, d5, d6, d7}, [DCT_TABLE, :128]!
+ vmul.s16 q14, q14, q2
+ vmul.s16 q13, q13, q1
+ vld1.16 {d0}, [ip, :64] /* load constants */
+ vmul.s16 q15, q15, q3
+ vpush {d8-d13} /* save NEON registers */
+ /* 1-D IDCT, pass 1 */
+ vsub.s16 q2, q10, q14
+ vadd.s16 q14, q10, q14
+ vsub.s16 q1, q11, q13
+ vadd.s16 q13, q11, q13
+ vsub.s16 q5, q9, q15
+ vadd.s16 q15, q9, q15
+ vqdmulh.s16 q4, q2, XFIX_1_414213562
+ vqdmulh.s16 q6, q1, XFIX_2_613125930
+ vadd.s16 q3, q1, q1
+ vsub.s16 q1, q5, q1
+ vadd.s16 q10, q2, q4
+ vqdmulh.s16 q4, q1, XFIX_1_847759065
+ vsub.s16 q2, q15, q13
+ vadd.s16 q3, q3, q6
+ vqdmulh.s16 q6, q2, XFIX_1_414213562
+ vadd.s16 q1, q1, q4
+ vqdmulh.s16 q4, q5, XFIX_1_082392200
+ vsub.s16 q10, q10, q14
+ vadd.s16 q2, q2, q6
+ vsub.s16 q6, q8, q12
+ vadd.s16 q12, q8, q12
+ vadd.s16 q9, q5, q4
+ vadd.s16 q5, q6, q10
+ vsub.s16 q10, q6, q10
+ vadd.s16 q6, q15, q13
+ vadd.s16 q8, q12, q14
+ vsub.s16 q3, q6, q3
+ vsub.s16 q12, q12, q14
+ vsub.s16 q3, q3, q1
+ vsub.s16 q1, q9, q1
+ vadd.s16 q2, q3, q2
+ vsub.s16 q15, q8, q6
+ vadd.s16 q1, q1, q2
+ vadd.s16 q8, q8, q6
+ vadd.s16 q14, q5, q3
+ vsub.s16 q9, q5, q3
+ vsub.s16 q13, q10, q2
+ vadd.s16 q10, q10, q2
+ /* Transpose */
+ vtrn.16 q8, q9
+ vsub.s16 q11, q12, q1
+ vtrn.16 q14, q15
+ vadd.s16 q12, q12, q1
+ vtrn.16 q10, q11
+ vtrn.16 q12, q13
+ vtrn.32 q9, q11
+ vtrn.32 q12, q14
+ vtrn.32 q8, q10
+ vtrn.32 q13, q15
+ vswp d28, d21
+ vswp d26, d19
+ /* 1-D IDCT, pass 2 */
+ vsub.s16 q2, q10, q14
+ vswp d30, d23
+ vadd.s16 q14, q10, q14
+ vswp d24, d17
+ vsub.s16 q1, q11, q13
+ vadd.s16 q13, q11, q13
+ vsub.s16 q5, q9, q15
+ vadd.s16 q15, q9, q15
+ vqdmulh.s16 q4, q2, XFIX_1_414213562
+ vqdmulh.s16 q6, q1, XFIX_2_613125930
+ vadd.s16 q3, q1, q1
+ vsub.s16 q1, q5, q1
+ vadd.s16 q10, q2, q4
+ vqdmulh.s16 q4, q1, XFIX_1_847759065
+ vsub.s16 q2, q15, q13
+ vadd.s16 q3, q3, q6
+ vqdmulh.s16 q6, q2, XFIX_1_414213562
+ vadd.s16 q1, q1, q4
+ vqdmulh.s16 q4, q5, XFIX_1_082392200
+ vsub.s16 q10, q10, q14
+ vadd.s16 q2, q2, q6
+ vsub.s16 q6, q8, q12
+ vadd.s16 q12, q8, q12
+ vadd.s16 q9, q5, q4
+ vadd.s16 q5, q6, q10
+ vsub.s16 q10, q6, q10
+ vadd.s16 q6, q15, q13
+ vadd.s16 q8, q12, q14
+ vsub.s16 q3, q6, q3
+ vsub.s16 q12, q12, q14
+ vsub.s16 q3, q3, q1
+ vsub.s16 q1, q9, q1
+ vadd.s16 q2, q3, q2
+ vsub.s16 q15, q8, q6
+ vadd.s16 q1, q1, q2
+ vadd.s16 q8, q8, q6
+ vadd.s16 q14, q5, q3
+ vsub.s16 q9, q5, q3
+ vsub.s16 q13, q10, q2
+ vpop {d8-d13} /* restore NEON registers */
+ vadd.s16 q10, q10, q2
+ vsub.s16 q11, q12, q1
+ vadd.s16 q12, q12, q1
+ /* Descale to 8-bit and range limit */
+ vmov.u8 q0, #0x80
+ vqshrn.s16 d16, q8, #5
+ vqshrn.s16 d17, q9, #5
+ vqshrn.s16 d18, q10, #5
+ vqshrn.s16 d19, q11, #5
+ vqshrn.s16 d20, q12, #5
+ vqshrn.s16 d21, q13, #5
+ vqshrn.s16 d22, q14, #5
+ vqshrn.s16 d23, q15, #5
+ vadd.u8 q8, q8, q0
+ vadd.u8 q9, q9, q0
+ vadd.u8 q10, q10, q0
+ vadd.u8 q11, q11, q0
+ /* Transpose the final 8-bit samples */
+ vtrn.16 q8, q9
+ vtrn.16 q10, q11
+ vtrn.32 q8, q10
+ vtrn.32 q9, q11
+ vtrn.8 d16, d17
+ vtrn.8 d18, d19
+ /* Store results to the output buffer */
+ ldmia OUTPUT_BUF!, {TMP1, TMP2}
+ add TMP1, TMP1, OUTPUT_COL
+ add TMP2, TMP2, OUTPUT_COL
+ vst1.8 {d16}, [TMP1]
+ vst1.8 {d17}, [TMP2]
+ ldmia OUTPUT_BUF!, {TMP1, TMP2}
+ add TMP1, TMP1, OUTPUT_COL
+ add TMP2, TMP2, OUTPUT_COL
+ vst1.8 {d18}, [TMP1]
+ vtrn.8 d20, d21
+ vst1.8 {d19}, [TMP2]
+ ldmia OUTPUT_BUF, {TMP1, TMP2, TMP3, TMP4}
+ add TMP1, TMP1, OUTPUT_COL
+ add TMP2, TMP2, OUTPUT_COL
+ add TMP3, TMP3, OUTPUT_COL
+ add TMP4, TMP4, OUTPUT_COL
+ vst1.8 {d20}, [TMP1]
+ vtrn.8 d22, d23
+ vst1.8 {d21}, [TMP2]
+ vst1.8 {d22}, [TMP3]
+ vst1.8 {d23}, [TMP4]
+ bx lr
+
+ .unreq DCT_TABLE
+ .unreq COEF_BLOCK
+ .unreq OUTPUT_BUF
+ .unreq OUTPUT_COL
+ .unreq TMP1
+ .unreq TMP2
+ .unreq TMP3
+ .unreq TMP4
+.endfunc
+
+/*****************************************************************************/
+
+/*
+ * jsimd_idct_4x4_neon
+ *
+ * This function contains inverse-DCT code for getting reduced-size
+ * 4x4 pixels output from an 8x8 DCT block. It uses the same calculations
+ * and produces exactly the same output as IJG's original 'jpeg_idct_4x4'
+ * function from jpeg-6b (jidctred.c).
+ *
+ * NOTE: jpeg-8 has an improved implementation of 4x4 inverse-DCT, which
+ * requires much less arithmetic operations and hence should be faster.
+ * The primary purpose of this particular NEON optimized function is
+ * bit exact compatibility with jpeg-6b.
+ *
+ * TODO: a bit better instructions scheduling can be achieved by expanding
+ * idct_helper/transpose_4x4 macros and reordering instructions,
+ * but readability will suffer somewhat.
+ */
+
+#define CONST_BITS 13
+
+#define FIX_0_211164243 (1730) /* FIX(0.211164243) */
+#define FIX_0_509795579 (4176) /* FIX(0.509795579) */
+#define FIX_0_601344887 (4926) /* FIX(0.601344887) */
+#define FIX_0_720959822 (5906) /* FIX(0.720959822) */
+#define FIX_0_765366865 (6270) /* FIX(0.765366865) */
+#define FIX_0_850430095 (6967) /* FIX(0.850430095) */
+#define FIX_0_899976223 (7373) /* FIX(0.899976223) */
+#define FIX_1_061594337 (8697) /* FIX(1.061594337) */
+#define FIX_1_272758580 (10426) /* FIX(1.272758580) */
+#define FIX_1_451774981 (11893) /* FIX(1.451774981) */
+#define FIX_1_847759065 (15137) /* FIX(1.847759065) */
+#define FIX_2_172734803 (17799) /* FIX(2.172734803) */
+#define FIX_2_562915447 (20995) /* FIX(2.562915447) */
+#define FIX_3_624509785 (29692) /* FIX(3.624509785) */
+
+.balign 16
+jsimd_idct_4x4_neon_consts:
+ .short FIX_1_847759065 /* d0[0] */
+ .short -FIX_0_765366865 /* d0[1] */
+ .short -FIX_0_211164243 /* d0[2] */
+ .short FIX_1_451774981 /* d0[3] */
+ .short -FIX_2_172734803 /* d1[0] */
+ .short FIX_1_061594337 /* d1[1] */
+ .short -FIX_0_509795579 /* d1[2] */
+ .short -FIX_0_601344887 /* d1[3] */
+ .short FIX_0_899976223 /* d2[0] */
+ .short FIX_2_562915447 /* d2[1] */
+ .short 1 << (CONST_BITS+1) /* d2[2] */
+ .short 0 /* d2[3] */
+
+.macro idct_helper x4, x6, x8, x10, x12, x14, x16, shift, y26, y27, y28, y29
+ vmull.s16 q14, \x4, d2[2]
+ vmlal.s16 q14, \x8, d0[0]
+ vmlal.s16 q14, \x14, d0[1]
+
+ vmull.s16 q13, \x16, d1[2]
+ vmlal.s16 q13, \x12, d1[3]
+ vmlal.s16 q13, \x10, d2[0]
+ vmlal.s16 q13, \x6, d2[1]
+
+ vmull.s16 q15, \x4, d2[2]
+ vmlsl.s16 q15, \x8, d0[0]
+ vmlsl.s16 q15, \x14, d0[1]
+
+ vmull.s16 q12, \x16, d0[2]
+ vmlal.s16 q12, \x12, d0[3]
+ vmlal.s16 q12, \x10, d1[0]
+ vmlal.s16 q12, \x6, d1[1]
+
+ vadd.s32 q10, q14, q13
+ vsub.s32 q14, q14, q13
+
+.if \shift > 16
+ vrshr.s32 q10, q10, #\shift
+ vrshr.s32 q14, q14, #\shift
+ vmovn.s32 \y26, q10
+ vmovn.s32 \y29, q14
+.else
+ vrshrn.s32 \y26, q10, #\shift
+ vrshrn.s32 \y29, q14, #\shift
+.endif
+
+ vadd.s32 q10, q15, q12
+ vsub.s32 q15, q15, q12
+
+.if \shift > 16
+ vrshr.s32 q10, q10, #\shift
+ vrshr.s32 q15, q15, #\shift
+ vmovn.s32 \y27, q10
+ vmovn.s32 \y28, q15
+.else
+ vrshrn.s32 \y27, q10, #\shift
+ vrshrn.s32 \y28, q15, #\shift
+.endif
+
+.endm
+
+asm_function jsimd_idct_4x4_neon
+
+ DCT_TABLE .req r0
+ COEF_BLOCK .req r1
+ OUTPUT_BUF .req r2
+ OUTPUT_COL .req r3
+ TMP1 .req r0
+ TMP2 .req r1
+ TMP3 .req r2
+ TMP4 .req ip
+
+ vpush {d8-d15}
+
+ /* Load constants (d3 is just used for padding) */
+ adr TMP4, jsimd_idct_4x4_neon_consts
+ vld1.16 {d0, d1, d2, d3}, [TMP4, :128]
+
+ /* Load all COEF_BLOCK into NEON registers with the following allocation:
+ * 0 1 2 3 | 4 5 6 7
+ * ---------+--------
+ * 0 | d4 | d5
+ * 1 | d6 | d7
+ * 2 | d8 | d9
+ * 3 | d10 | d11
+ * 4 | - | -
+ * 5 | d12 | d13
+ * 6 | d14 | d15
+ * 7 | d16 | d17
+ */
+ vld1.16 {d4, d5, d6, d7}, [COEF_BLOCK, :128]!
+ vld1.16 {d8, d9, d10, d11}, [COEF_BLOCK, :128]!
+ add COEF_BLOCK, COEF_BLOCK, #16
+ vld1.16 {d12, d13, d14, d15}, [COEF_BLOCK, :128]!
+ vld1.16 {d16, d17}, [COEF_BLOCK, :128]!
+ /* dequantize */
+ vld1.16 {d18, d19, d20, d21}, [DCT_TABLE, :128]!
+ vmul.s16 q2, q2, q9
+ vld1.16 {d22, d23, d24, d25}, [DCT_TABLE, :128]!
+ vmul.s16 q3, q3, q10
+ vmul.s16 q4, q4, q11
+ add DCT_TABLE, DCT_TABLE, #16
+ vld1.16 {d26, d27, d28, d29}, [DCT_TABLE, :128]!
+ vmul.s16 q5, q5, q12
+ vmul.s16 q6, q6, q13
+ vld1.16 {d30, d31}, [DCT_TABLE, :128]!
+ vmul.s16 q7, q7, q14
+ vmul.s16 q8, q8, q15
+
+ /* Pass 1 */
+ idct_helper d4, d6, d8, d10, d12, d14, d16, 12, d4, d6, d8, d10
+ transpose_4x4 d4, d6, d8, d10
+ idct_helper d5, d7, d9, d11, d13, d15, d17, 12, d5, d7, d9, d11
+ transpose_4x4 d5, d7, d9, d11
+
+ /* Pass 2 */
+ idct_helper d4, d6, d8, d10, d7, d9, d11, 19, d26, d27, d28, d29
+ transpose_4x4 d26, d27, d28, d29
+
+ /* Range limit */
+ vmov.u16 q15, #0x80
+ vadd.s16 q13, q13, q15
+ vadd.s16 q14, q14, q15
+ vqmovun.s16 d26, q13
+ vqmovun.s16 d27, q14
+
+ /* Store results to the output buffer */
+ ldmia OUTPUT_BUF, {TMP1, TMP2, TMP3, TMP4}
+ add TMP1, TMP1, OUTPUT_COL
+ add TMP2, TMP2, OUTPUT_COL
+ add TMP3, TMP3, OUTPUT_COL
+ add TMP4, TMP4, OUTPUT_COL
+
+#if defined(__ARMEL__) && !RESPECT_STRICT_ALIGNMENT
+ /* We can use much less instructions on little endian systems if the
+ * OS kernel is not configured to trap unaligned memory accesses
+ */
+ vst1.32 {d26[0]}, [TMP1]!
+ vst1.32 {d27[0]}, [TMP3]!
+ vst1.32 {d26[1]}, [TMP2]!
+ vst1.32 {d27[1]}, [TMP4]!
+#else
+ vst1.8 {d26[0]}, [TMP1]!
+ vst1.8 {d27[0]}, [TMP3]!
+ vst1.8 {d26[1]}, [TMP1]!
+ vst1.8 {d27[1]}, [TMP3]!
+ vst1.8 {d26[2]}, [TMP1]!
+ vst1.8 {d27[2]}, [TMP3]!
+ vst1.8 {d26[3]}, [TMP1]!
+ vst1.8 {d27[3]}, [TMP3]!
+
+ vst1.8 {d26[4]}, [TMP2]!
+ vst1.8 {d27[4]}, [TMP4]!
+ vst1.8 {d26[5]}, [TMP2]!
+ vst1.8 {d27[5]}, [TMP4]!
+ vst1.8 {d26[6]}, [TMP2]!
+ vst1.8 {d27[6]}, [TMP4]!
+ vst1.8 {d26[7]}, [TMP2]!
+ vst1.8 {d27[7]}, [TMP4]!
+#endif
+
+ vpop {d8-d15}
+ bx lr
+
+ .unreq DCT_TABLE
+ .unreq COEF_BLOCK
+ .unreq OUTPUT_BUF
+ .unreq OUTPUT_COL
+ .unreq TMP1
+ .unreq TMP2
+ .unreq TMP3
+ .unreq TMP4
+.endfunc
+
+.purgem idct_helper
+
+/*****************************************************************************/
+
+/*
+ * jsimd_idct_2x2_neon
+ *
+ * This function contains inverse-DCT code for getting reduced-size
+ * 2x2 pixels output from an 8x8 DCT block. It uses the same calculations
+ * and produces exactly the same output as IJG's original 'jpeg_idct_2x2'
+ * function from jpeg-6b (jidctred.c).
+ *
+ * NOTE: jpeg-8 has an improved implementation of 2x2 inverse-DCT, which
+ * requires much less arithmetic operations and hence should be faster.
+ * The primary purpose of this particular NEON optimized function is
+ * bit exact compatibility with jpeg-6b.
+ */
+
+.balign 8
+jsimd_idct_2x2_neon_consts:
+ .short -FIX_0_720959822 /* d0[0] */
+ .short FIX_0_850430095 /* d0[1] */
+ .short -FIX_1_272758580 /* d0[2] */
+ .short FIX_3_624509785 /* d0[3] */
+
+.macro idct_helper x4, x6, x10, x12, x16, shift, y26, y27
+ vshll.s16 q14, \x4, #15
+ vmull.s16 q13, \x6, d0[3]
+ vmlal.s16 q13, \x10, d0[2]
+ vmlal.s16 q13, \x12, d0[1]
+ vmlal.s16 q13, \x16, d0[0]
+
+ vadd.s32 q10, q14, q13
+ vsub.s32 q14, q14, q13
+
+.if \shift > 16
+ vrshr.s32 q10, q10, #\shift
+ vrshr.s32 q14, q14, #\shift
+ vmovn.s32 \y26, q10
+ vmovn.s32 \y27, q14
+.else
+ vrshrn.s32 \y26, q10, #\shift
+ vrshrn.s32 \y27, q14, #\shift
+.endif
+
+.endm
+
+asm_function jsimd_idct_2x2_neon
+
+ DCT_TABLE .req r0
+ COEF_BLOCK .req r1
+ OUTPUT_BUF .req r2
+ OUTPUT_COL .req r3
+ TMP1 .req r0
+ TMP2 .req ip
+
+ vpush {d8-d15}
+
+ /* Load constants */
+ adr TMP2, jsimd_idct_2x2_neon_consts
+ vld1.16 {d0}, [TMP2, :64]
+
+ /* Load all COEF_BLOCK into NEON registers with the following allocation:
+ * 0 1 2 3 | 4 5 6 7
+ * ---------+--------
+ * 0 | d4 | d5
+ * 1 | d6 | d7
+ * 2 | - | -
+ * 3 | d10 | d11
+ * 4 | - | -
+ * 5 | d12 | d13
+ * 6 | - | -
+ * 7 | d16 | d17
+ */
+ vld1.16 {d4, d5, d6, d7}, [COEF_BLOCK, :128]!
+ add COEF_BLOCK, COEF_BLOCK, #16
+ vld1.16 {d10, d11}, [COEF_BLOCK, :128]!
+ add COEF_BLOCK, COEF_BLOCK, #16
+ vld1.16 {d12, d13}, [COEF_BLOCK, :128]!
+ add COEF_BLOCK, COEF_BLOCK, #16
+ vld1.16 {d16, d17}, [COEF_BLOCK, :128]!
+ /* Dequantize */
+ vld1.16 {d18, d19, d20, d21}, [DCT_TABLE, :128]!
+ vmul.s16 q2, q2, q9
+ vmul.s16 q3, q3, q10
+ add DCT_TABLE, DCT_TABLE, #16
+ vld1.16 {d24, d25}, [DCT_TABLE, :128]!
+ vmul.s16 q5, q5, q12
+ add DCT_TABLE, DCT_TABLE, #16
+ vld1.16 {d26, d27}, [DCT_TABLE, :128]!
+ vmul.s16 q6, q6, q13
+ add DCT_TABLE, DCT_TABLE, #16
+ vld1.16 {d30, d31}, [DCT_TABLE, :128]!
+ vmul.s16 q8, q8, q15
+
+ /* Pass 1 */
+#if 0
+ idct_helper d4, d6, d10, d12, d16, 13, d4, d6
+ transpose_4x4 d4, d6, d8, d10
+ idct_helper d5, d7, d11, d13, d17, 13, d5, d7
+ transpose_4x4 d5, d7, d9, d11
+#else
+ vmull.s16 q13, d6, d0[3]
+ vmlal.s16 q13, d10, d0[2]
+ vmlal.s16 q13, d12, d0[1]
+ vmlal.s16 q13, d16, d0[0]
+ vmull.s16 q12, d7, d0[3]
+ vmlal.s16 q12, d11, d0[2]
+ vmlal.s16 q12, d13, d0[1]
+ vmlal.s16 q12, d17, d0[0]
+ vshll.s16 q14, d4, #15
+ vshll.s16 q15, d5, #15
+ vadd.s32 q10, q14, q13
+ vsub.s32 q14, q14, q13
+ vrshrn.s32 d4, q10, #13
+ vrshrn.s32 d6, q14, #13
+ vadd.s32 q10, q15, q12
+ vsub.s32 q14, q15, q12
+ vrshrn.s32 d5, q10, #13
+ vrshrn.s32 d7, q14, #13
+ vtrn.16 q2, q3
+ vtrn.32 q3, q5
+#endif
+
+ /* Pass 2 */
+ idct_helper d4, d6, d10, d7, d11, 20, d26, d27
+
+ /* Range limit */
+ vmov.u16 q15, #0x80
+ vadd.s16 q13, q13, q15
+ vqmovun.s16 d26, q13
+ vqmovun.s16 d27, q13
+
+ /* Store results to the output buffer */
+ ldmia OUTPUT_BUF, {TMP1, TMP2}
+ add TMP1, TMP1, OUTPUT_COL
+ add TMP2, TMP2, OUTPUT_COL
+
+ vst1.8 {d26[0]}, [TMP1]!
+ vst1.8 {d27[4]}, [TMP1]!
+ vst1.8 {d26[1]}, [TMP2]!
+ vst1.8 {d27[5]}, [TMP2]!
+
+ vpop {d8-d15}
+ bx lr
+
+ .unreq DCT_TABLE
+ .unreq COEF_BLOCK
+ .unreq OUTPUT_BUF
+ .unreq OUTPUT_COL
+ .unreq TMP1
+ .unreq TMP2
+.endfunc
+
+.purgem idct_helper
+
+/*****************************************************************************/
+
+/*
+ * jsimd_ycc_extrgb_convert_neon
+ * jsimd_ycc_extbgr_convert_neon
+ * jsimd_ycc_extrgbx_convert_neon
+ * jsimd_ycc_extbgrx_convert_neon
+ * jsimd_ycc_extxbgr_convert_neon
+ * jsimd_ycc_extxrgb_convert_neon
+ *
+ * Colorspace conversion YCbCr -> RGB
+ */
+
+
+.macro do_load size
+ .if \size == 8
+ vld1.8 {d4}, [U, :64]!
+ vld1.8 {d5}, [V, :64]!
+ vld1.8 {d0}, [Y, :64]!
+ pld [U, #64]
+ pld [V, #64]
+ pld [Y, #64]
+ .elseif \size == 4
+ vld1.8 {d4[0]}, [U]!
+ vld1.8 {d4[1]}, [U]!
+ vld1.8 {d4[2]}, [U]!
+ vld1.8 {d4[3]}, [U]!
+ vld1.8 {d5[0]}, [V]!
+ vld1.8 {d5[1]}, [V]!
+ vld1.8 {d5[2]}, [V]!
+ vld1.8 {d5[3]}, [V]!
+ vld1.8 {d0[0]}, [Y]!
+ vld1.8 {d0[1]}, [Y]!
+ vld1.8 {d0[2]}, [Y]!
+ vld1.8 {d0[3]}, [Y]!
+ .elseif \size == 2
+ vld1.8 {d4[4]}, [U]!
+ vld1.8 {d4[5]}, [U]!
+ vld1.8 {d5[4]}, [V]!
+ vld1.8 {d5[5]}, [V]!
+ vld1.8 {d0[4]}, [Y]!
+ vld1.8 {d0[5]}, [Y]!
+ .elseif \size == 1
+ vld1.8 {d4[6]}, [U]!
+ vld1.8 {d5[6]}, [V]!
+ vld1.8 {d0[6]}, [Y]!
+ .else
+ .error unsupported macroblock size
+ .endif
+.endm
+
+.macro do_store bpp, size
+ .if \bpp == 24
+ .if \size == 8
+ vst3.8 {d10, d11, d12}, [RGB]!
+ .elseif \size == 4
+ vst3.8 {d10[0], d11[0], d12[0]}, [RGB]!
+ vst3.8 {d10[1], d11[1], d12[1]}, [RGB]!
+ vst3.8 {d10[2], d11[2], d12[2]}, [RGB]!
+ vst3.8 {d10[3], d11[3], d12[3]}, [RGB]!
+ .elseif \size == 2
+ vst3.8 {d10[4], d11[4], d12[4]}, [RGB]!
+ vst3.8 {d10[5], d11[5], d12[5]}, [RGB]!
+ .elseif \size == 1
+ vst3.8 {d10[6], d11[6], d12[6]}, [RGB]!
+ .else
+ .error unsupported macroblock size
+ .endif
+ .elseif \bpp == 32
+ .if \size == 8
+ vst4.8 {d10, d11, d12, d13}, [RGB]!
+ .elseif \size == 4
+ vst4.8 {d10[0], d11[0], d12[0], d13[0]}, [RGB]!
+ vst4.8 {d10[1], d11[1], d12[1], d13[1]}, [RGB]!
+ vst4.8 {d10[2], d11[2], d12[2], d13[2]}, [RGB]!
+ vst4.8 {d10[3], d11[3], d12[3], d13[3]}, [RGB]!
+ .elseif \size == 2
+ vst4.8 {d10[4], d11[4], d12[4], d13[4]}, [RGB]!
+ vst4.8 {d10[5], d11[5], d12[5], d13[5]}, [RGB]!
+ .elseif \size == 1
+ vst4.8 {d10[6], d11[6], d12[6], d13[6]}, [RGB]!
+ .else
+ .error unsupported macroblock size
+ .endif
+ .else
+ .error unsupported bpp
+ .endif
+.endm
+
+.macro generate_jsimd_ycc_rgb_convert_neon colorid, bpp, r_offs, g_offs, b_offs
+
+/*
+ * 2 stage pipelined YCbCr->RGB conversion
+ */
+
+.macro do_yuv_to_rgb_stage1
+ vaddw.u8 q3, q1, d4 /* q3 = u - 128 */
+ vaddw.u8 q4, q1, d5 /* q2 = v - 128 */
+ vmull.s16 q10, d6, d1[1] /* multiply by -11277 */
+ vmlal.s16 q10, d8, d1[2] /* multiply by -23401 */
+ vmull.s16 q11, d7, d1[1] /* multiply by -11277 */
+ vmlal.s16 q11, d9, d1[2] /* multiply by -23401 */
+ vmull.s16 q12, d8, d1[0] /* multiply by 22971 */
+ vmull.s16 q13, d9, d1[0] /* multiply by 22971 */
+ vmull.s16 q14, d6, d1[3] /* multiply by 29033 */
+ vmull.s16 q15, d7, d1[3] /* multiply by 29033 */
+.endm
+
+.macro do_yuv_to_rgb_stage2
+ vrshrn.s32 d20, q10, #15
+ vrshrn.s32 d21, q11, #15
+ vrshrn.s32 d24, q12, #14
+ vrshrn.s32 d25, q13, #14
+ vrshrn.s32 d28, q14, #14
+ vrshrn.s32 d29, q15, #14
+ vaddw.u8 q10, q10, d0
+ vaddw.u8 q12, q12, d0
+ vaddw.u8 q14, q14, d0
+ vqmovun.s16 d1\g_offs, q10
+ vqmovun.s16 d1\r_offs, q12
+ vqmovun.s16 d1\b_offs, q14
+.endm
+
+.macro do_yuv_to_rgb_stage2_store_load_stage1
+ vld1.8 {d4}, [U, :64]!
+ vrshrn.s32 d20, q10, #15
+ vrshrn.s32 d21, q11, #15
+ vrshrn.s32 d24, q12, #14
+ vrshrn.s32 d25, q13, #14
+ vrshrn.s32 d28, q14, #14
+ vld1.8 {d5}, [V, :64]!
+ vrshrn.s32 d29, q15, #14
+ vaddw.u8 q10, q10, d0
+ vaddw.u8 q12, q12, d0
+ vaddw.u8 q14, q14, d0
+ vqmovun.s16 d1\g_offs, q10
+ vld1.8 {d0}, [Y, :64]!
+ vqmovun.s16 d1\r_offs, q12
+ pld [U, #64]
+ pld [V, #64]
+ pld [Y, #64]
+ vqmovun.s16 d1\b_offs, q14
+ vaddw.u8 q3, q1, d4 /* q3 = u - 128 */
+ vaddw.u8 q4, q1, d5 /* q2 = v - 128 */
+ do_store \bpp, 8
+ vmull.s16 q10, d6, d1[1] /* multiply by -11277 */
+ vmlal.s16 q10, d8, d1[2] /* multiply by -23401 */
+ vmull.s16 q11, d7, d1[1] /* multiply by -11277 */
+ vmlal.s16 q11, d9, d1[2] /* multiply by -23401 */
+ vmull.s16 q12, d8, d1[0] /* multiply by 22971 */
+ vmull.s16 q13, d9, d1[0] /* multiply by 22971 */
+ vmull.s16 q14, d6, d1[3] /* multiply by 29033 */
+ vmull.s16 q15, d7, d1[3] /* multiply by 29033 */
+.endm
+
+.macro do_yuv_to_rgb
+ do_yuv_to_rgb_stage1
+ do_yuv_to_rgb_stage2
+.endm
+
+/* Apple gas crashes on adrl, work around that by using adr.
+ * But this requires a copy of these constants for each function.
+ */
+
+.balign 16
+jsimd_ycc_\colorid\()_neon_consts:
+ .short 0, 0, 0, 0
+ .short 22971, -11277, -23401, 29033
+ .short -128, -128, -128, -128
+ .short -128, -128, -128, -128
+
+asm_function jsimd_ycc_\colorid\()_convert_neon
+ OUTPUT_WIDTH .req r0
+ INPUT_BUF .req r1
+ INPUT_ROW .req r2
+ OUTPUT_BUF .req r3
+ NUM_ROWS .req r4
+
+ INPUT_BUF0 .req r5
+ INPUT_BUF1 .req r6
+ INPUT_BUF2 .req INPUT_BUF
+
+ RGB .req r7
+ Y .req r8
+ U .req r9
+ V .req r10
+ N .req ip
+
+ /* Load constants to d1, d2, d3 (d0 is just used for padding) */
+ adr ip, jsimd_ycc_\colorid\()_neon_consts
+ vld1.16 {d0, d1, d2, d3}, [ip, :128]
+
+ /* Save ARM registers and handle input arguments */
+ push {r4, r5, r6, r7, r8, r9, r10, lr}
+ ldr NUM_ROWS, [sp, #(4 * 8)]
+ ldr INPUT_BUF0, [INPUT_BUF]
+ ldr INPUT_BUF1, [INPUT_BUF, #4]
+ ldr INPUT_BUF2, [INPUT_BUF, #8]
+ .unreq INPUT_BUF
+
+ /* Save NEON registers */
+ vpush {d8-d15}
+
+ /* Initially set d10, d11, d12, d13 to 0xFF */
+ vmov.u8 q5, #255
+ vmov.u8 q6, #255
+
+ /* Outer loop over scanlines */
+ cmp NUM_ROWS, #1
+ blt 9f
+0:
+ ldr Y, [INPUT_BUF0, INPUT_ROW, lsl #2]
+ ldr U, [INPUT_BUF1, INPUT_ROW, lsl #2]
+ mov N, OUTPUT_WIDTH
+ ldr V, [INPUT_BUF2, INPUT_ROW, lsl #2]
+ add INPUT_ROW, INPUT_ROW, #1
+ ldr RGB, [OUTPUT_BUF], #4
+
+ /* Inner loop over pixels */
+ subs N, N, #8
+ blt 3f
+ do_load 8
+ do_yuv_to_rgb_stage1
+ subs N, N, #8
+ blt 2f
+1:
+ do_yuv_to_rgb_stage2_store_load_stage1
+ subs N, N, #8
+ bge 1b
+2:
+ do_yuv_to_rgb_stage2
+ do_store \bpp, 8
+ tst N, #7
+ beq 8f
+3:
+ tst N, #4
+ beq 3f
+ do_load 4
+3:
+ tst N, #2
+ beq 4f
+ do_load 2
+4:
+ tst N, #1
+ beq 5f
+ do_load 1
+5:
+ do_yuv_to_rgb
+ tst N, #4
+ beq 6f
+ do_store \bpp, 4
+6:
+ tst N, #2
+ beq 7f
+ do_store \bpp, 2
+7:
+ tst N, #1
+ beq 8f
+ do_store \bpp, 1
+8:
+ subs NUM_ROWS, NUM_ROWS, #1
+ bgt 0b
+9:
+ /* Restore all registers and return */
+ vpop {d8-d15}
+ pop {r4, r5, r6, r7, r8, r9, r10, pc}
+
+ .unreq OUTPUT_WIDTH
+ .unreq INPUT_ROW
+ .unreq OUTPUT_BUF
+ .unreq NUM_ROWS
+ .unreq INPUT_BUF0
+ .unreq INPUT_BUF1
+ .unreq INPUT_BUF2
+ .unreq RGB
+ .unreq Y
+ .unreq U
+ .unreq V
+ .unreq N
+.endfunc
+
+.purgem do_yuv_to_rgb
+.purgem do_yuv_to_rgb_stage1
+.purgem do_yuv_to_rgb_stage2
+.purgem do_yuv_to_rgb_stage2_store_load_stage1
+
+.endm
+
+/*--------------------------------- id ----- bpp R G B */
+generate_jsimd_ycc_rgb_convert_neon extrgb, 24, 0, 1, 2
+generate_jsimd_ycc_rgb_convert_neon extbgr, 24, 2, 1, 0
+generate_jsimd_ycc_rgb_convert_neon extrgbx, 32, 0, 1, 2
+generate_jsimd_ycc_rgb_convert_neon extbgrx, 32, 2, 1, 0
+generate_jsimd_ycc_rgb_convert_neon extxbgr, 32, 3, 2, 1
+generate_jsimd_ycc_rgb_convert_neon extxrgb, 32, 1, 2, 3
+
+.purgem do_load
+.purgem do_store
+
+/*****************************************************************************/
+
+/*
+ * jsimd_extrgb_ycc_convert_neon
+ * jsimd_extbgr_ycc_convert_neon
+ * jsimd_extrgbx_ycc_convert_neon
+ * jsimd_extbgrx_ycc_convert_neon
+ * jsimd_extxbgr_ycc_convert_neon
+ * jsimd_extxrgb_ycc_convert_neon
+ *
+ * Colorspace conversion RGB -> YCbCr
+ */
+
+.macro do_store size
+ .if \size == 8
+ vst1.8 {d20}, [Y]!
+ vst1.8 {d21}, [U]!
+ vst1.8 {d22}, [V]!
+ .elseif \size == 4
+ vst1.8 {d20[0]}, [Y]!
+ vst1.8 {d20[1]}, [Y]!
+ vst1.8 {d20[2]}, [Y]!
+ vst1.8 {d20[3]}, [Y]!
+ vst1.8 {d21[0]}, [U]!
+ vst1.8 {d21[1]}, [U]!
+ vst1.8 {d21[2]}, [U]!
+ vst1.8 {d21[3]}, [U]!
+ vst1.8 {d22[0]}, [V]!
+ vst1.8 {d22[1]}, [V]!
+ vst1.8 {d22[2]}, [V]!
+ vst1.8 {d22[3]}, [V]!
+ .elseif \size == 2
+ vst1.8 {d20[4]}, [Y]!
+ vst1.8 {d20[5]}, [Y]!
+ vst1.8 {d21[4]}, [U]!
+ vst1.8 {d21[5]}, [U]!
+ vst1.8 {d22[4]}, [V]!
+ vst1.8 {d22[5]}, [V]!
+ .elseif \size == 1
+ vst1.8 {d20[6]}, [Y]!
+ vst1.8 {d21[6]}, [U]!
+ vst1.8 {d22[6]}, [V]!
+ .else
+ .error unsupported macroblock size
+ .endif
+.endm
+
+.macro do_load bpp, size
+ .if \bpp == 24
+ .if \size == 8
+ vld3.8 {d10, d11, d12}, [RGB]!
+ pld [RGB, #128]
+ .elseif \size == 4
+ vld3.8 {d10[0], d11[0], d12[0]}, [RGB]!
+ vld3.8 {d10[1], d11[1], d12[1]}, [RGB]!
+ vld3.8 {d10[2], d11[2], d12[2]}, [RGB]!
+ vld3.8 {d10[3], d11[3], d12[3]}, [RGB]!
+ .elseif \size == 2
+ vld3.8 {d10[4], d11[4], d12[4]}, [RGB]!
+ vld3.8 {d10[5], d11[5], d12[5]}, [RGB]!
+ .elseif \size == 1
+ vld3.8 {d10[6], d11[6], d12[6]}, [RGB]!
+ .else
+ .error unsupported macroblock size
+ .endif
+ .elseif \bpp == 32
+ .if \size == 8
+ vld4.8 {d10, d11, d12, d13}, [RGB]!
+ pld [RGB, #128]
+ .elseif \size == 4
+ vld4.8 {d10[0], d11[0], d12[0], d13[0]}, [RGB]!
+ vld4.8 {d10[1], d11[1], d12[1], d13[1]}, [RGB]!
+ vld4.8 {d10[2], d11[2], d12[2], d13[2]}, [RGB]!
+ vld4.8 {d10[3], d11[3], d12[3], d13[3]}, [RGB]!
+ .elseif \size == 2
+ vld4.8 {d10[4], d11[4], d12[4], d13[4]}, [RGB]!
+ vld4.8 {d10[5], d11[5], d12[5], d13[5]}, [RGB]!
+ .elseif \size == 1
+ vld4.8 {d10[6], d11[6], d12[6], d13[6]}, [RGB]!
+ .else
+ .error unsupported macroblock size
+ .endif
+ .else
+ .error unsupported bpp
+ .endif
+.endm
+
+.macro generate_jsimd_rgb_ycc_convert_neon colorid, bpp, r_offs, g_offs, b_offs
+
+/*
+ * 2 stage pipelined RGB->YCbCr conversion
+ */
+
+.macro do_rgb_to_yuv_stage1
+ vmovl.u8 q2, d1\r_offs /* r = { d4, d5 } */
+ vmovl.u8 q3, d1\g_offs /* g = { d6, d7 } */
+ vmovl.u8 q4, d1\b_offs /* b = { d8, d9 } */
+ vmull.u16 q7, d4, d0[0]
+ vmlal.u16 q7, d6, d0[1]
+ vmlal.u16 q7, d8, d0[2]
+ vmull.u16 q8, d5, d0[0]
+ vmlal.u16 q8, d7, d0[1]
+ vmlal.u16 q8, d9, d0[2]
+ vrev64.32 q9, q1
+ vrev64.32 q13, q1
+ vmlsl.u16 q9, d4, d0[3]
+ vmlsl.u16 q9, d6, d1[0]
+ vmlal.u16 q9, d8, d1[1]
+ vmlsl.u16 q13, d5, d0[3]
+ vmlsl.u16 q13, d7, d1[0]
+ vmlal.u16 q13, d9, d1[1]
+ vrev64.32 q14, q1
+ vrev64.32 q15, q1
+ vmlal.u16 q14, d4, d1[1]
+ vmlsl.u16 q14, d6, d1[2]
+ vmlsl.u16 q14, d8, d1[3]
+ vmlal.u16 q15, d5, d1[1]
+ vmlsl.u16 q15, d7, d1[2]
+ vmlsl.u16 q15, d9, d1[3]
+.endm
+
+.macro do_rgb_to_yuv_stage2
+ vrshrn.u32 d20, q7, #16
+ vrshrn.u32 d21, q8, #16
+ vshrn.u32 d22, q9, #16
+ vshrn.u32 d23, q13, #16
+ vshrn.u32 d24, q14, #16
+ vshrn.u32 d25, q15, #16
+ vmovn.u16 d20, q10 /* d20 = y */
+ vmovn.u16 d21, q11 /* d21 = u */
+ vmovn.u16 d22, q12 /* d22 = v */
+.endm
+
+.macro do_rgb_to_yuv
+ do_rgb_to_yuv_stage1
+ do_rgb_to_yuv_stage2
+.endm
+
+.macro do_rgb_to_yuv_stage2_store_load_stage1
+ vrshrn.u32 d20, q7, #16
+ vrshrn.u32 d21, q8, #16
+ vshrn.u32 d22, q9, #16
+ vrev64.32 q9, q1
+ vshrn.u32 d23, q13, #16
+ vrev64.32 q13, q1
+ vshrn.u32 d24, q14, #16
+ vshrn.u32 d25, q15, #16
+ do_load \bpp, 8
+ vmovn.u16 d20, q10 /* d20 = y */
+ vmovl.u8 q2, d1\r_offs /* r = { d4, d5 } */
+ vmovn.u16 d21, q11 /* d21 = u */
+ vmovl.u8 q3, d1\g_offs /* g = { d6, d7 } */
+ vmovn.u16 d22, q12 /* d22 = v */
+ vmovl.u8 q4, d1\b_offs /* b = { d8, d9 } */
+ vmull.u16 q7, d4, d0[0]
+ vmlal.u16 q7, d6, d0[1]
+ vmlal.u16 q7, d8, d0[2]
+ vst1.8 {d20}, [Y]!
+ vmull.u16 q8, d5, d0[0]
+ vmlal.u16 q8, d7, d0[1]
+ vmlal.u16 q8, d9, d0[2]
+ vmlsl.u16 q9, d4, d0[3]
+ vmlsl.u16 q9, d6, d1[0]
+ vmlal.u16 q9, d8, d1[1]
+ vst1.8 {d21}, [U]!
+ vmlsl.u16 q13, d5, d0[3]
+ vmlsl.u16 q13, d7, d1[0]
+ vmlal.u16 q13, d9, d1[1]
+ vrev64.32 q14, q1
+ vrev64.32 q15, q1
+ vmlal.u16 q14, d4, d1[1]
+ vmlsl.u16 q14, d6, d1[2]
+ vmlsl.u16 q14, d8, d1[3]
+ vst1.8 {d22}, [V]!
+ vmlal.u16 q15, d5, d1[1]
+ vmlsl.u16 q15, d7, d1[2]
+ vmlsl.u16 q15, d9, d1[3]
+.endm
+
+.balign 16
+jsimd_\colorid\()_ycc_neon_consts:
+ .short 19595, 38470, 7471, 11059
+ .short 21709, 32768, 27439, 5329
+ .short 32767, 128, 32767, 128
+ .short 32767, 128, 32767, 128
+
+asm_function jsimd_\colorid\()_ycc_convert_neon
+ OUTPUT_WIDTH .req r0
+ INPUT_BUF .req r1
+ OUTPUT_BUF .req r2
+ OUTPUT_ROW .req r3
+ NUM_ROWS .req r4
+
+ OUTPUT_BUF0 .req r5
+ OUTPUT_BUF1 .req r6
+ OUTPUT_BUF2 .req OUTPUT_BUF
+
+ RGB .req r7
+ Y .req r8
+ U .req r9
+ V .req r10
+ N .req ip
+
+ /* Load constants to d0, d1, d2, d3 */
+ adr ip, jsimd_\colorid\()_ycc_neon_consts
+ vld1.16 {d0, d1, d2, d3}, [ip, :128]
+
+ /* Save ARM registers and handle input arguments */
+ push {r4, r5, r6, r7, r8, r9, r10, lr}
+ ldr NUM_ROWS, [sp, #(4 * 8)]
+ ldr OUTPUT_BUF0, [OUTPUT_BUF]
+ ldr OUTPUT_BUF1, [OUTPUT_BUF, #4]
+ ldr OUTPUT_BUF2, [OUTPUT_BUF, #8]
+ .unreq OUTPUT_BUF
+
+ /* Save NEON registers */
+ vpush {d8-d15}
+
+ /* Outer loop over scanlines */
+ cmp NUM_ROWS, #1
+ blt 9f
+0:
+ ldr Y, [OUTPUT_BUF0, OUTPUT_ROW, lsl #2]
+ ldr U, [OUTPUT_BUF1, OUTPUT_ROW, lsl #2]
+ mov N, OUTPUT_WIDTH
+ ldr V, [OUTPUT_BUF2, OUTPUT_ROW, lsl #2]
+ add OUTPUT_ROW, OUTPUT_ROW, #1
+ ldr RGB, [INPUT_BUF], #4
+
+ /* Inner loop over pixels */
+ subs N, N, #8
+ blt 3f
+ do_load \bpp, 8
+ do_rgb_to_yuv_stage1
+ subs N, N, #8
+ blt 2f
+1:
+ do_rgb_to_yuv_stage2_store_load_stage1
+ subs N, N, #8
+ bge 1b
+2:
+ do_rgb_to_yuv_stage2
+ do_store 8
+ tst N, #7
+ beq 8f
+3:
+ tst N, #4
+ beq 3f
+ do_load \bpp, 4
+3:
+ tst N, #2
+ beq 4f
+ do_load \bpp, 2
+4:
+ tst N, #1
+ beq 5f
+ do_load \bpp, 1
+5:
+ do_rgb_to_yuv
+ tst N, #4
+ beq 6f
+ do_store 4
+6:
+ tst N, #2
+ beq 7f
+ do_store 2
+7:
+ tst N, #1
+ beq 8f
+ do_store 1
+8:
+ subs NUM_ROWS, NUM_ROWS, #1
+ bgt 0b
+9:
+ /* Restore all registers and return */
+ vpop {d8-d15}
+ pop {r4, r5, r6, r7, r8, r9, r10, pc}
+
+ .unreq OUTPUT_WIDTH
+ .unreq OUTPUT_ROW
+ .unreq INPUT_BUF
+ .unreq NUM_ROWS
+ .unreq OUTPUT_BUF0
+ .unreq OUTPUT_BUF1
+ .unreq OUTPUT_BUF2
+ .unreq RGB
+ .unreq Y
+ .unreq U
+ .unreq V
+ .unreq N
+.endfunc
+
+.purgem do_rgb_to_yuv
+.purgem do_rgb_to_yuv_stage1
+.purgem do_rgb_to_yuv_stage2
+.purgem do_rgb_to_yuv_stage2_store_load_stage1
+
+.endm
+
+/*--------------------------------- id ----- bpp R G B */
+generate_jsimd_rgb_ycc_convert_neon extrgb, 24, 0, 1, 2
+generate_jsimd_rgb_ycc_convert_neon extbgr, 24, 2, 1, 0
+generate_jsimd_rgb_ycc_convert_neon extrgbx, 32, 0, 1, 2
+generate_jsimd_rgb_ycc_convert_neon extbgrx, 32, 2, 1, 0
+generate_jsimd_rgb_ycc_convert_neon extxbgr, 32, 3, 2, 1
+generate_jsimd_rgb_ycc_convert_neon extxrgb, 32, 1, 2, 3
+
+.purgem do_load
+.purgem do_store
+
+/*****************************************************************************/
+
+/*
+ * Load data into workspace, applying unsigned->signed conversion
+ *
+ * TODO: can be combined with 'jsimd_fdct_ifast_neon' to get
+ * rid of VST1.16 instructions
+ */
+
+asm_function jsimd_convsamp_neon
+ SAMPLE_DATA .req r0
+ START_COL .req r1
+ WORKSPACE .req r2
+ TMP1 .req r3
+ TMP2 .req r4
+ TMP3 .req r5
+ TMP4 .req ip
+
+ push {r4, r5}
+ vmov.u8 d0, #128
+
+ ldmia SAMPLE_DATA!, {TMP1, TMP2, TMP3, TMP4}
+ add TMP1, TMP1, START_COL
+ add TMP2, TMP2, START_COL
+ add TMP3, TMP3, START_COL
+ add TMP4, TMP4, START_COL
+ vld1.8 {d16}, [TMP1]
+ vsubl.u8 q8, d16, d0
+ vld1.8 {d18}, [TMP2]
+ vsubl.u8 q9, d18, d0
+ vld1.8 {d20}, [TMP3]
+ vsubl.u8 q10, d20, d0
+ vld1.8 {d22}, [TMP4]
+ ldmia SAMPLE_DATA!, {TMP1, TMP2, TMP3, TMP4}
+ vsubl.u8 q11, d22, d0
+ vst1.16 {d16, d17, d18, d19}, [WORKSPACE, :128]!
+ add TMP1, TMP1, START_COL
+ add TMP2, TMP2, START_COL
+ vst1.16 {d20, d21, d22, d23}, [WORKSPACE, :128]!
+ add TMP3, TMP3, START_COL
+ add TMP4, TMP4, START_COL
+ vld1.8 {d24}, [TMP1]
+ vsubl.u8 q12, d24, d0
+ vld1.8 {d26}, [TMP2]
+ vsubl.u8 q13, d26, d0
+ vld1.8 {d28}, [TMP3]
+ vsubl.u8 q14, d28, d0
+ vld1.8 {d30}, [TMP4]
+ vsubl.u8 q15, d30, d0
+ vst1.16 {d24, d25, d26, d27}, [WORKSPACE, :128]!
+ vst1.16 {d28, d29, d30, d31}, [WORKSPACE, :128]!
+ pop {r4, r5}
+ bx lr
+
+ .unreq SAMPLE_DATA
+ .unreq START_COL
+ .unreq WORKSPACE
+ .unreq TMP1
+ .unreq TMP2
+ .unreq TMP3
+ .unreq TMP4
+.endfunc
+
+/*****************************************************************************/
+
+/*
+ * jsimd_fdct_ifast_neon
+ *
+ * This function contains a fast, not so accurate integer implementation of
+ * the forward DCT (Discrete Cosine Transform). It uses the same calculations
+ * and produces exactly the same output as IJG's original 'jpeg_fdct_ifast'
+ * function from jfdctfst.c
+ *
+ * TODO: can be combined with 'jsimd_convsamp_neon' to get
+ * rid of a bunch of VLD1.16 instructions
+ */
+
+#define XFIX_0_382683433 d0[0]
+#define XFIX_0_541196100 d0[1]
+#define XFIX_0_707106781 d0[2]
+#define XFIX_1_306562965 d0[3]
+
+.balign 16
+jsimd_fdct_ifast_neon_consts:
+ .short (98 * 128) /* XFIX_0_382683433 */
+ .short (139 * 128) /* XFIX_0_541196100 */
+ .short (181 * 128) /* XFIX_0_707106781 */
+ .short (334 * 128 - 256 * 128) /* XFIX_1_306562965 */
+
+asm_function jsimd_fdct_ifast_neon
+
+ DATA .req r0
+ TMP .req ip
+
+ vpush {d8-d15}
+
+ /* Load constants */
+ adr TMP, jsimd_fdct_ifast_neon_consts
+ vld1.16 {d0}, [TMP, :64]
+
+ /* Load all DATA into NEON registers with the following allocation:
+ * 0 1 2 3 | 4 5 6 7
+ * ---------+--------
+ * 0 | d16 | d17 | q8
+ * 1 | d18 | d19 | q9
+ * 2 | d20 | d21 | q10
+ * 3 | d22 | d23 | q11
+ * 4 | d24 | d25 | q12
+ * 5 | d26 | d27 | q13
+ * 6 | d28 | d29 | q14
+ * 7 | d30 | d31 | q15
+ */
+
+ vld1.16 {d16, d17, d18, d19}, [DATA, :128]!
+ vld1.16 {d20, d21, d22, d23}, [DATA, :128]!
+ vld1.16 {d24, d25, d26, d27}, [DATA, :128]!
+ vld1.16 {d28, d29, d30, d31}, [DATA, :128]
+ sub DATA, DATA, #(128 - 32)
+
+ mov TMP, #2
+1:
+ /* Transpose */
+ vtrn.16 q12, q13
+ vtrn.16 q10, q11
+ vtrn.16 q8, q9
+ vtrn.16 q14, q15
+ vtrn.32 q9, q11
+ vtrn.32 q13, q15
+ vtrn.32 q8, q10
+ vtrn.32 q12, q14
+ vswp d30, d23
+ vswp d24, d17
+ vswp d26, d19
+ /* 1-D FDCT */
+ vadd.s16 q2, q11, q12
+ vswp d28, d21
+ vsub.s16 q12, q11, q12
+ vsub.s16 q6, q10, q13
+ vadd.s16 q10, q10, q13
+ vsub.s16 q7, q9, q14
+ vadd.s16 q9, q9, q14
+ vsub.s16 q1, q8, q15
+ vadd.s16 q8, q8, q15
+ vsub.s16 q4, q9, q10
+ vsub.s16 q5, q8, q2
+ vadd.s16 q3, q9, q10
+ vadd.s16 q4, q4, q5
+ vadd.s16 q2, q8, q2
+ vqdmulh.s16 q4, q4, XFIX_0_707106781
+ vadd.s16 q11, q12, q6
+ vadd.s16 q8, q2, q3
+ vsub.s16 q12, q2, q3
+ vadd.s16 q3, q6, q7
+ vadd.s16 q7, q7, q1
+ vqdmulh.s16 q3, q3, XFIX_0_707106781
+ vsub.s16 q6, q11, q7
+ vadd.s16 q10, q5, q4
+ vqdmulh.s16 q6, q6, XFIX_0_382683433
+ vsub.s16 q14, q5, q4
+ vqdmulh.s16 q11, q11, XFIX_0_541196100
+ vqdmulh.s16 q5, q7, XFIX_1_306562965
+ vadd.s16 q4, q1, q3
+ vsub.s16 q3, q1, q3
+ vadd.s16 q7, q7, q6
+ vadd.s16 q11, q11, q6
+ vadd.s16 q7, q7, q5
+ vadd.s16 q13, q3, q11
+ vsub.s16 q11, q3, q11
+ vadd.s16 q9, q4, q7
+ vsub.s16 q15, q4, q7
+ subs TMP, TMP, #1
+ bne 1b
+
+ /* store results */
+ vst1.16 {d16, d17, d18, d19}, [DATA, :128]!
+ vst1.16 {d20, d21, d22, d23}, [DATA, :128]!
+ vst1.16 {d24, d25, d26, d27}, [DATA, :128]!
+ vst1.16 {d28, d29, d30, d31}, [DATA, :128]
+
+ vpop {d8-d15}
+ bx lr
+
+ .unreq DATA
+ .unreq TMP
+.endfunc
+
+/*****************************************************************************/
+
+/*
+ * GLOBAL(void)
+ * jsimd_quantize_neon (JCOEFPTR coef_block, DCTELEM * divisors,
+ * DCTELEM * workspace);
+ *
+ * Note: the code uses 2 stage pipelining in order to improve instructions
+ * scheduling and eliminate stalls (this provides ~15% better
+ * performance for this function on both ARM Cortex-A8 and
+ * ARM Cortex-A9 when compared to the non-pipelined variant).
+ * The instructions which belong to the second stage use different
+ * indentation for better readiability.
+ */
+asm_function jsimd_quantize_neon
+
+ COEF_BLOCK .req r0
+ DIVISORS .req r1
+ WORKSPACE .req r2
+
+ RECIPROCAL .req DIVISORS
+ CORRECTION .req r3
+ SHIFT .req ip
+ LOOP_COUNT .req r4
+
+ vld1.16 {d0, d1, d2, d3}, [WORKSPACE, :128]!
+ vabs.s16 q12, q0
+ add CORRECTION, DIVISORS, #(64 * 2)
+ add SHIFT, DIVISORS, #(64 * 6)
+ vld1.16 {d20, d21, d22, d23}, [CORRECTION, :128]!
+ vabs.s16 q13, q1
+ vld1.16 {d16, d17, d18, d19}, [RECIPROCAL, :128]!
+ vadd.u16 q12, q12, q10 /* add correction */
+ vadd.u16 q13, q13, q11
+ vmull.u16 q10, d24, d16 /* multiply by reciprocal */
+ vmull.u16 q11, d25, d17
+ vmull.u16 q8, d26, d18
+ vmull.u16 q9, d27, d19
+ vld1.16 {d24, d25, d26, d27}, [SHIFT, :128]!
+ vshrn.u32 d20, q10, #16
+ vshrn.u32 d21, q11, #16
+ vshrn.u32 d22, q8, #16
+ vshrn.u32 d23, q9, #16
+ vneg.s16 q12, q12
+ vneg.s16 q13, q13
+ vshr.s16 q2, q0, #15 /* extract sign */
+ vshr.s16 q3, q1, #15
+ vshl.u16 q14, q10, q12 /* shift */
+ vshl.u16 q15, q11, q13
+
+ push {r4, r5}
+ mov LOOP_COUNT, #3
+1:
+ vld1.16 {d0, d1, d2, d3}, [WORKSPACE, :128]!
+ veor.u16 q14, q14, q2 /* restore sign */
+ vabs.s16 q12, q0
+ vld1.16 {d20, d21, d22, d23}, [CORRECTION, :128]!
+ vabs.s16 q13, q1
+ veor.u16 q15, q15, q3
+ vld1.16 {d16, d17, d18, d19}, [RECIPROCAL, :128]!
+ vadd.u16 q12, q12, q10 /* add correction */
+ vadd.u16 q13, q13, q11
+ vmull.u16 q10, d24, d16 /* multiply by reciprocal */
+ vmull.u16 q11, d25, d17
+ vmull.u16 q8, d26, d18
+ vmull.u16 q9, d27, d19
+ vsub.u16 q14, q14, q2
+ vld1.16 {d24, d25, d26, d27}, [SHIFT, :128]!
+ vsub.u16 q15, q15, q3
+ vshrn.u32 d20, q10, #16
+ vshrn.u32 d21, q11, #16
+ vst1.16 {d28, d29, d30, d31}, [COEF_BLOCK, :128]!
+ vshrn.u32 d22, q8, #16
+ vshrn.u32 d23, q9, #16
+ vneg.s16 q12, q12
+ vneg.s16 q13, q13
+ vshr.s16 q2, q0, #15 /* extract sign */
+ vshr.s16 q3, q1, #15
+ vshl.u16 q14, q10, q12 /* shift */
+ vshl.u16 q15, q11, q13
+ subs LOOP_COUNT, LOOP_COUNT, #1
+ bne 1b
+ pop {r4, r5}
+
+ veor.u16 q14, q14, q2 /* restore sign */
+ veor.u16 q15, q15, q3
+ vsub.u16 q14, q14, q2
+ vsub.u16 q15, q15, q3
+ vst1.16 {d28, d29, d30, d31}, [COEF_BLOCK, :128]!
+
+ bx lr /* return */
+
+ .unreq COEF_BLOCK
+ .unreq DIVISORS
+ .unreq WORKSPACE
+ .unreq RECIPROCAL
+ .unreq CORRECTION
+ .unreq SHIFT
+ .unreq LOOP_COUNT
+.endfunc
+
+/*****************************************************************************/
+
+/*
+ * GLOBAL(void)
+ * jsimd_h2v1_fancy_upsample_neon (int max_v_samp_factor,
+ * JDIMENSION downsampled_width,
+ * JSAMPARRAY input_data,
+ * JSAMPARRAY * output_data_ptr);
+ *
+ * Note: the use of unaligned writes is the main remaining bottleneck in
+ * this code, which can be potentially solved to get up to tens
+ * of percents performance improvement on Cortex-A8/Cortex-A9.
+ */
+
+/*
+ * Upsample 16 source pixels to 32 destination pixels. The new 16 source
+ * pixels are loaded to q0. The previous 16 source pixels are in q1. The
+ * shifted-by-one source pixels are constructed in q2 by using q0 and q1.
+ * Register d28 is used for multiplication by 3. Register q15 is used
+ * for adding +1 bias.
+ */
+.macro upsample16 OUTPTR, INPTR
+ vld1.8 {q0}, [\INPTR]!
+ vmovl.u8 q8, d0
+ vext.8 q2, q1, q0, #15
+ vmovl.u8 q9, d1
+ vaddw.u8 q10, q15, d4
+ vaddw.u8 q11, q15, d5
+ vmlal.u8 q8, d4, d28
+ vmlal.u8 q9, d5, d28
+ vmlal.u8 q10, d0, d28
+ vmlal.u8 q11, d1, d28
+ vmov q1, q0 /* backup source pixels to q1 */
+ vrshrn.u16 d6, q8, #2
+ vrshrn.u16 d7, q9, #2
+ vshrn.u16 d8, q10, #2
+ vshrn.u16 d9, q11, #2
+ vst2.8 {d6, d7, d8, d9}, [\OUTPTR]!
+.endm
+
+/*
+ * Upsample 32 source pixels to 64 destination pixels. Compared to 'usample16'
+ * macro, the roles of q0 and q1 registers are reversed for even and odd
+ * groups of 16 pixels, that's why "vmov q1, q0" instructions are not needed.
+ * Also this unrolling allows to reorder loads and stores to compensate
+ * multiplication latency and reduce stalls.
+ */
+.macro upsample32 OUTPTR, INPTR
+ /* even 16 pixels group */
+ vld1.8 {q0}, [\INPTR]!
+ vmovl.u8 q8, d0
+ vext.8 q2, q1, q0, #15
+ vmovl.u8 q9, d1
+ vaddw.u8 q10, q15, d4
+ vaddw.u8 q11, q15, d5
+ vmlal.u8 q8, d4, d28
+ vmlal.u8 q9, d5, d28
+ vmlal.u8 q10, d0, d28
+ vmlal.u8 q11, d1, d28
+ /* odd 16 pixels group */
+ vld1.8 {q1}, [\INPTR]!
+ vrshrn.u16 d6, q8, #2
+ vrshrn.u16 d7, q9, #2
+ vshrn.u16 d8, q10, #2
+ vshrn.u16 d9, q11, #2
+ vmovl.u8 q8, d2
+ vext.8 q2, q0, q1, #15
+ vmovl.u8 q9, d3
+ vaddw.u8 q10, q15, d4
+ vaddw.u8 q11, q15, d5
+ vmlal.u8 q8, d4, d28
+ vmlal.u8 q9, d5, d28
+ vmlal.u8 q10, d2, d28
+ vmlal.u8 q11, d3, d28
+ vst2.8 {d6, d7, d8, d9}, [\OUTPTR]!
+ vrshrn.u16 d6, q8, #2
+ vrshrn.u16 d7, q9, #2
+ vshrn.u16 d8, q10, #2
+ vshrn.u16 d9, q11, #2
+ vst2.8 {d6, d7, d8, d9}, [\OUTPTR]!
+.endm
+
+/*
+ * Upsample a row of WIDTH pixels from INPTR to OUTPTR.
+ */
+.macro upsample_row OUTPTR, INPTR, WIDTH, TMP1
+ /* special case for the first and last pixels */
+ sub \WIDTH, \WIDTH, #1
+ add \OUTPTR, \OUTPTR, #1
+ ldrb \TMP1, [\INPTR, \WIDTH]
+ strb \TMP1, [\OUTPTR, \WIDTH, asl #1]
+ ldrb \TMP1, [\INPTR], #1
+ strb \TMP1, [\OUTPTR, #-1]
+ vmov.8 d3[7], \TMP1
+
+ subs \WIDTH, \WIDTH, #32
+ blt 5f
+0: /* process 32 pixels per iteration */
+ upsample32 \OUTPTR, \INPTR
+ subs \WIDTH, \WIDTH, #32
+ bge 0b
+5:
+ adds \WIDTH, \WIDTH, #16
+ blt 1f
+0: /* process 16 pixels if needed */
+ upsample16 \OUTPTR, \INPTR
+ subs \WIDTH, \WIDTH, #16
+1:
+ adds \WIDTH, \WIDTH, #16
+ beq 9f
+
+ /* load the remaining 1-15 pixels */
+ add \INPTR, \INPTR, \WIDTH
+ tst \WIDTH, #1
+ beq 2f
+ sub \INPTR, \INPTR, #1
+ vld1.8 {d0[0]}, [\INPTR]
+2:
+ tst \WIDTH, #2
+ beq 2f
+ vext.8 d0, d0, d0, #6
+ sub \INPTR, \INPTR, #1
+ vld1.8 {d0[1]}, [\INPTR]
+ sub \INPTR, \INPTR, #1
+ vld1.8 {d0[0]}, [\INPTR]
+2:
+ tst \WIDTH, #4
+ beq 2f
+ vrev64.32 d0, d0
+ sub \INPTR, \INPTR, #1
+ vld1.8 {d0[3]}, [\INPTR]
+ sub \INPTR, \INPTR, #1
+ vld1.8 {d0[2]}, [\INPTR]
+ sub \INPTR, \INPTR, #1
+ vld1.8 {d0[1]}, [\INPTR]
+ sub \INPTR, \INPTR, #1
+ vld1.8 {d0[0]}, [\INPTR]
+2:
+ tst \WIDTH, #8
+ beq 2f
+ vmov d1, d0
+ sub \INPTR, \INPTR, #8
+ vld1.8 {d0}, [\INPTR]
+2: /* upsample the remaining pixels */
+ vmovl.u8 q8, d0
+ vext.8 q2, q1, q0, #15
+ vmovl.u8 q9, d1
+ vaddw.u8 q10, q15, d4
+ vaddw.u8 q11, q15, d5
+ vmlal.u8 q8, d4, d28
+ vmlal.u8 q9, d5, d28
+ vmlal.u8 q10, d0, d28
+ vmlal.u8 q11, d1, d28
+ vrshrn.u16 d10, q8, #2
+ vrshrn.u16 d12, q9, #2
+ vshrn.u16 d11, q10, #2
+ vshrn.u16 d13, q11, #2
+ vzip.8 d10, d11
+ vzip.8 d12, d13
+ /* store the remaining pixels */
+ tst \WIDTH, #8
+ beq 2f
+ vst1.8 {d10, d11}, [\OUTPTR]!
+ vmov q5, q6
+2:
+ tst \WIDTH, #4
+ beq 2f
+ vst1.8 {d10}, [\OUTPTR]!
+ vmov d10, d11
+2:
+ tst \WIDTH, #2
+ beq 2f
+ vst1.8 {d10[0]}, [\OUTPTR]!
+ vst1.8 {d10[1]}, [\OUTPTR]!
+ vst1.8 {d10[2]}, [\OUTPTR]!
+ vst1.8 {d10[3]}, [\OUTPTR]!
+ vext.8 d10, d10, d10, #4
+2:
+ tst \WIDTH, #1
+ beq 2f
+ vst1.8 {d10[0]}, [\OUTPTR]!
+ vst1.8 {d10[1]}, [\OUTPTR]!
+2:
+9:
+.endm
+
+asm_function jsimd_h2v1_fancy_upsample_neon
+
+ MAX_V_SAMP_FACTOR .req r0
+ DOWNSAMPLED_WIDTH .req r1
+ INPUT_DATA .req r2
+ OUTPUT_DATA_PTR .req r3
+ OUTPUT_DATA .req OUTPUT_DATA_PTR
+
+ OUTPTR .req r4
+ INPTR .req r5
+ WIDTH .req ip
+ TMP .req lr
+
+ push {r4, r5, r6, lr}
+ vpush {d8-d15}
+
+ ldr OUTPUT_DATA, [OUTPUT_DATA_PTR]
+ cmp MAX_V_SAMP_FACTOR, #0
+ ble 99f
+
+ /* initialize constants */
+ vmov.u8 d28, #3
+ vmov.u16 q15, #1
+11:
+ ldr INPTR, [INPUT_DATA], #4
+ ldr OUTPTR, [OUTPUT_DATA], #4
+ mov WIDTH, DOWNSAMPLED_WIDTH
+ upsample_row OUTPTR, INPTR, WIDTH, TMP
+ subs MAX_V_SAMP_FACTOR, MAX_V_SAMP_FACTOR, #1
+ bgt 11b
+
+99:
+ vpop {d8-d15}
+ pop {r4, r5, r6, pc}
+
+ .unreq MAX_V_SAMP_FACTOR
+ .unreq DOWNSAMPLED_WIDTH
+ .unreq INPUT_DATA
+ .unreq OUTPUT_DATA_PTR
+ .unreq OUTPUT_DATA
+
+ .unreq OUTPTR
+ .unreq INPTR
+ .unreq WIDTH
+ .unreq TMP
+
+.endfunc
+
+.purgem upsample16
+.purgem upsample32
+.purgem upsample_row