src/third_party/libvpx/vp9/common/arm/neon/vp9_iht_neon.h - cobalt - Git at Google

 /*
  *  Copyright (c) 2018 The WebM project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */

 #ifndef VPX_VP9_COMMON_ARM_NEON_VP9_IHT_NEON_H_
 #define VPX_VP9_COMMON_ARM_NEON_VP9_IHT_NEON_H_

 #include <arm_neon.h>

 #include "./vp9_rtcd.h"
 #include "./vpx_config.h"
 #include "vp9/common/vp9_common.h"
 #include "vpx_dsp/arm/idct_neon.h"
 #include "vpx_dsp/arm/mem_neon.h"
 #include "vpx_dsp/txfm_common.h"

 static INLINE void iadst4(int16x8_t *const io) {
   const int32x4_t c3 = vdupq_n_s32(sinpi_3_9);
   int16x4_t x[4];
   int32x4_t s[8], output[4];
   const int16x4_t c =
       create_s16x4_neon(sinpi_1_9, sinpi_2_9, sinpi_3_9, sinpi_4_9);

   x[0] = vget_low_s16(io[0]);
   x[1] = vget_low_s16(io[1]);
   x[2] = vget_high_s16(io[0]);
   x[3] = vget_high_s16(io[1]);

   s[0] = vmull_lane_s16(x[0], c, 0);
   s[1] = vmull_lane_s16(x[0], c, 1);
   s[2] = vmull_lane_s16(x[1], c, 2);
   s[3] = vmull_lane_s16(x[2], c, 3);
   s[4] = vmull_lane_s16(x[2], c, 0);
   s[5] = vmull_lane_s16(x[3], c, 1);
   s[6] = vmull_lane_s16(x[3], c, 3);
   s[7] = vaddl_s16(x[0], x[3]);
   s[7] = vsubw_s16(s[7], x[2]);

   s[0] = vaddq_s32(s[0], s[3]);
   s[0] = vaddq_s32(s[0], s[5]);
   s[1] = vsubq_s32(s[1], s[4]);
   s[1] = vsubq_s32(s[1], s[6]);
   s[3] = s[2];
   s[2] = vmulq_s32(c3, s[7]);

   output[0] = vaddq_s32(s[0], s[3]);
   output[1] = vaddq_s32(s[1], s[3]);
   output[2] = s[2];
   output[3] = vaddq_s32(s[0], s[1]);
   output[3] = vsubq_s32(output[3], s[3]);
   dct_const_round_shift_low_8_dual(output, &io[0], &io[1]);
 }

 static INLINE void iadst_half_butterfly_neon(int16x8_t *const x,
                                              const int16x4_t c) {
   // Don't add/sub before multiply, which will overflow in iadst8.
   const int32x4_t x0_lo = vmull_lane_s16(vget_low_s16(x[0]), c, 0);
   const int32x4_t x0_hi = vmull_lane_s16(vget_high_s16(x[0]), c, 0);
   const int32x4_t x1_lo = vmull_lane_s16(vget_low_s16(x[1]), c, 0);
   const int32x4_t x1_hi = vmull_lane_s16(vget_high_s16(x[1]), c, 0);
   int32x4_t t0[2], t1[2];

   t0[0] = vaddq_s32(x0_lo, x1_lo);
   t0[1] = vaddq_s32(x0_hi, x1_hi);
   t1[0] = vsubq_s32(x0_lo, x1_lo);
   t1[1] = vsubq_s32(x0_hi, x1_hi);
   x[0] = dct_const_round_shift_low_8(t0);
   x[1] = dct_const_round_shift_low_8(t1);
 }

 static INLINE void iadst_half_butterfly_neg_neon(int16x8_t *const x0,
                                                  int16x8_t *const x1,
                                                  const int16x4_t c) {
   // Don't add/sub before multiply, which will overflow in iadst8.
   const int32x4_t x0_lo = vmull_lane_s16(vget_low_s16(*x0), c, 1);
   const int32x4_t x0_hi = vmull_lane_s16(vget_high_s16(*x0), c, 1);
   const int32x4_t x1_lo = vmull_lane_s16(vget_low_s16(*x1), c, 1);
   const int32x4_t x1_hi = vmull_lane_s16(vget_high_s16(*x1), c, 1);
   int32x4_t t0[2], t1[2];

   t0[0] = vaddq_s32(x0_lo, x1_lo);
   t0[1] = vaddq_s32(x0_hi, x1_hi);
   t1[0] = vsubq_s32(x0_lo, x1_lo);
   t1[1] = vsubq_s32(x0_hi, x1_hi);
   *x1 = dct_const_round_shift_low_8(t0);
   *x0 = dct_const_round_shift_low_8(t1);
 }

 static INLINE void iadst_half_butterfly_pos_neon(int16x8_t *const x0,
                                                  int16x8_t *const x1,
                                                  const int16x4_t c) {
   // Don't add/sub before multiply, which will overflow in iadst8.
   const int32x4_t x0_lo = vmull_lane_s16(vget_low_s16(*x0), c, 0);
   const int32x4_t x0_hi = vmull_lane_s16(vget_high_s16(*x0), c, 0);
   const int32x4_t x1_lo = vmull_lane_s16(vget_low_s16(*x1), c, 0);
   const int32x4_t x1_hi = vmull_lane_s16(vget_high_s16(*x1), c, 0);
   int32x4_t t0[2], t1[2];

   t0[0] = vaddq_s32(x0_lo, x1_lo);
   t0[1] = vaddq_s32(x0_hi, x1_hi);
   t1[0] = vsubq_s32(x0_lo, x1_lo);
   t1[1] = vsubq_s32(x0_hi, x1_hi);
   *x1 = dct_const_round_shift_low_8(t0);
   *x0 = dct_const_round_shift_low_8(t1);
 }

 static INLINE void iadst_butterfly_lane_0_1_neon(const int16x8_t in0,
                                                  const int16x8_t in1,
                                                  const int16x4_t c,
                                                  int32x4_t *const s0,
                                                  int32x4_t *const s1) {
   s0[0] = vmull_lane_s16(vget_low_s16(in0), c, 0);
   s0[1] = vmull_lane_s16(vget_high_s16(in0), c, 0);
   s1[0] = vmull_lane_s16(vget_low_s16(in0), c, 1);
   s1[1] = vmull_lane_s16(vget_high_s16(in0), c, 1);

   s0[0] = vmlal_lane_s16(s0[0], vget_low_s16(in1), c, 1);
   s0[1] = vmlal_lane_s16(s0[1], vget_high_s16(in1), c, 1);
   s1[0] = vmlsl_lane_s16(s1[0], vget_low_s16(in1), c, 0);
   s1[1] = vmlsl_lane_s16(s1[1], vget_high_s16(in1), c, 0);
 }

 static INLINE void iadst_butterfly_lane_2_3_neon(const int16x8_t in0,
                                                  const int16x8_t in1,
                                                  const int16x4_t c,
                                                  int32x4_t *const s0,
                                                  int32x4_t *const s1) {
   s0[0] = vmull_lane_s16(vget_low_s16(in0), c, 2);
   s0[1] = vmull_lane_s16(vget_high_s16(in0), c, 2);
   s1[0] = vmull_lane_s16(vget_low_s16(in0), c, 3);
   s1[1] = vmull_lane_s16(vget_high_s16(in0), c, 3);

   s0[0] = vmlal_lane_s16(s0[0], vget_low_s16(in1), c, 3);
   s0[1] = vmlal_lane_s16(s0[1], vget_high_s16(in1), c, 3);
   s1[0] = vmlsl_lane_s16(s1[0], vget_low_s16(in1), c, 2);
   s1[1] = vmlsl_lane_s16(s1[1], vget_high_s16(in1), c, 2);
 }

 static INLINE void iadst_butterfly_lane_1_0_neon(const int16x8_t in0,
                                                  const int16x8_t in1,
                                                  const int16x4_t c,
                                                  int32x4_t *const s0,
                                                  int32x4_t *const s1) {
   s0[0] = vmull_lane_s16(vget_low_s16(in0), c, 1);
   s0[1] = vmull_lane_s16(vget_high_s16(in0), c, 1);
   s1[0] = vmull_lane_s16(vget_low_s16(in0), c, 0);
   s1[1] = vmull_lane_s16(vget_high_s16(in0), c, 0);

   s0[0] = vmlal_lane_s16(s0[0], vget_low_s16(in1), c, 0);
   s0[1] = vmlal_lane_s16(s0[1], vget_high_s16(in1), c, 0);
   s1[0] = vmlsl_lane_s16(s1[0], vget_low_s16(in1), c, 1);
   s1[1] = vmlsl_lane_s16(s1[1], vget_high_s16(in1), c, 1);
 }

 static INLINE void iadst_butterfly_lane_3_2_neon(const int16x8_t in0,
                                                  const int16x8_t in1,
                                                  const int16x4_t c,
                                                  int32x4_t *const s0,
                                                  int32x4_t *const s1) {
   s0[0] = vmull_lane_s16(vget_low_s16(in0), c, 3);
   s0[1] = vmull_lane_s16(vget_high_s16(in0), c, 3);
   s1[0] = vmull_lane_s16(vget_low_s16(in0), c, 2);
   s1[1] = vmull_lane_s16(vget_high_s16(in0), c, 2);

   s0[0] = vmlal_lane_s16(s0[0], vget_low_s16(in1), c, 2);
   s0[1] = vmlal_lane_s16(s0[1], vget_high_s16(in1), c, 2);
   s1[0] = vmlsl_lane_s16(s1[0], vget_low_s16(in1), c, 3);
   s1[1] = vmlsl_lane_s16(s1[1], vget_high_s16(in1), c, 3);
 }

 static INLINE int16x8_t add_dct_const_round_shift_low_8(
     const int32x4_t *const in0, const int32x4_t *const in1) {
   int32x4_t sum[2];

   sum[0] = vaddq_s32(in0[0], in1[0]);
   sum[1] = vaddq_s32(in0[1], in1[1]);
   return dct_const_round_shift_low_8(sum);
 }

 static INLINE int16x8_t sub_dct_const_round_shift_low_8(
     const int32x4_t *const in0, const int32x4_t *const in1) {
   int32x4_t sum[2];

   sum[0] = vsubq_s32(in0[0], in1[0]);
   sum[1] = vsubq_s32(in0[1], in1[1]);
   return dct_const_round_shift_low_8(sum);
 }

 static INLINE void iadst8(int16x8_t *const io) {
   const int16x4_t c0 =
       create_s16x4_neon(cospi_2_64, cospi_30_64, cospi_10_64, cospi_22_64);
   const int16x4_t c1 =
       create_s16x4_neon(cospi_18_64, cospi_14_64, cospi_26_64, cospi_6_64);
   const int16x4_t c2 =
       create_s16x4_neon(cospi_16_64, 0, cospi_8_64, cospi_24_64);
   int16x8_t x[8], t[4];
   int32x4_t s0[2], s1[2], s2[2], s3[2], s4[2], s5[2], s6[2], s7[2];

   x[0] = io[7];
   x[1] = io[0];
   x[2] = io[5];
   x[3] = io[2];
   x[4] = io[3];
   x[5] = io[4];
   x[6] = io[1];
   x[7] = io[6];

   // stage 1
   iadst_butterfly_lane_0_1_neon(x[0], x[1], c0, s0, s1);
   iadst_butterfly_lane_2_3_neon(x[2], x[3], c0, s2, s3);
   iadst_butterfly_lane_0_1_neon(x[4], x[5], c1, s4, s5);
   iadst_butterfly_lane_2_3_neon(x[6], x[7], c1, s6, s7);

   x[0] = add_dct_const_round_shift_low_8(s0, s4);
   x[1] = add_dct_const_round_shift_low_8(s1, s5);
   x[2] = add_dct_const_round_shift_low_8(s2, s6);
   x[3] = add_dct_const_round_shift_low_8(s3, s7);
   x[4] = sub_dct_const_round_shift_low_8(s0, s4);
   x[5] = sub_dct_const_round_shift_low_8(s1, s5);
   x[6] = sub_dct_const_round_shift_low_8(s2, s6);
   x[7] = sub_dct_const_round_shift_low_8(s3, s7);

   // stage 2
   t[0] = x[0];
   t[1] = x[1];
   t[2] = x[2];
   t[3] = x[3];
   iadst_butterfly_lane_2_3_neon(x[4], x[5], c2, s4, s5);
   iadst_butterfly_lane_3_2_neon(x[7], x[6], c2, s7, s6);

   x[0] = vaddq_s16(t[0], t[2]);
   x[1] = vaddq_s16(t[1], t[3]);
   x[2] = vsubq_s16(t[0], t[2]);
   x[3] = vsubq_s16(t[1], t[3]);
   x[4] = add_dct_const_round_shift_low_8(s4, s6);
   x[5] = add_dct_const_round_shift_low_8(s5, s7);
   x[6] = sub_dct_const_round_shift_low_8(s4, s6);
   x[7] = sub_dct_const_round_shift_low_8(s5, s7);

   // stage 3
   iadst_half_butterfly_neon(x + 2, c2);
   iadst_half_butterfly_neon(x + 6, c2);

   io[0] = x[0];
   io[1] = vnegq_s16(x[4]);
   io[2] = x[6];
   io[3] = vnegq_s16(x[2]);
   io[4] = x[3];
   io[5] = vnegq_s16(x[7]);
   io[6] = x[5];
   io[7] = vnegq_s16(x[1]);
 }

 void vpx_iadst16x16_256_add_half1d(const void *const input, int16_t *output,
                                    void *const dest, const int stride,
                                    const int highbd_flag);

 typedef void (*iht_1d)(const void *const input, int16_t *output,
                        void *const dest, const int stride,
                        const int highbd_flag);

 typedef struct {
   iht_1d cols, rows;  // vertical and horizontal
 } iht_2d;

 #endif  // VPX_VP9_COMMON_ARM_NEON_VP9_IHT_NEON_H_
	/*
	* Copyright (c) 2018 The WebM project authors. All Rights Reserved.
	*
	* Use of this source code is governed by a BSD-style license
	* that can be found in the LICENSE file in the root of the source
	* tree. An additional intellectual property rights grant can be found
	* in the file PATENTS. All contributing project authors may
	* be found in the AUTHORS file in the root of the source tree.
	*/

	#ifndef VPX_VP9_COMMON_ARM_NEON_VP9_IHT_NEON_H_
	#define VPX_VP9_COMMON_ARM_NEON_VP9_IHT_NEON_H_

	#include <arm_neon.h>

	#include "./vp9_rtcd.h"
	#include "./vpx_config.h"
	#include "vp9/common/vp9_common.h"
	#include "vpx_dsp/arm/idct_neon.h"
	#include "vpx_dsp/arm/mem_neon.h"
	#include "vpx_dsp/txfm_common.h"

	static INLINE void iadst4(int16x8_t *const io) {
	const int32x4_t c3 = vdupq_n_s32(sinpi_3_9);
	int16x4_t x[4];
	int32x4_t s[8], output[4];
	const int16x4_t c =
	create_s16x4_neon(sinpi_1_9, sinpi_2_9, sinpi_3_9, sinpi_4_9);

	x[0] = vget_low_s16(io[0]);
	x[1] = vget_low_s16(io[1]);
	x[2] = vget_high_s16(io[0]);
	x[3] = vget_high_s16(io[1]);

	s[0] = vmull_lane_s16(x[0], c, 0);
	s[1] = vmull_lane_s16(x[0], c, 1);
	s[2] = vmull_lane_s16(x[1], c, 2);
	s[3] = vmull_lane_s16(x[2], c, 3);
	s[4] = vmull_lane_s16(x[2], c, 0);
	s[5] = vmull_lane_s16(x[3], c, 1);
	s[6] = vmull_lane_s16(x[3], c, 3);
	s[7] = vaddl_s16(x[0], x[3]);
	s[7] = vsubw_s16(s[7], x[2]);

	s[0] = vaddq_s32(s[0], s[3]);
	s[0] = vaddq_s32(s[0], s[5]);
	s[1] = vsubq_s32(s[1], s[4]);
	s[1] = vsubq_s32(s[1], s[6]);
	s[3] = s[2];
	s[2] = vmulq_s32(c3, s[7]);

	output[0] = vaddq_s32(s[0], s[3]);
	output[1] = vaddq_s32(s[1], s[3]);
	output[2] = s[2];
	output[3] = vaddq_s32(s[0], s[1]);
	output[3] = vsubq_s32(output[3], s[3]);
	dct_const_round_shift_low_8_dual(output, &io[0], &io[1]);
	}

	static INLINE void iadst_half_butterfly_neon(int16x8_t *const x,
	const int16x4_t c) {
	// Don't add/sub before multiply, which will overflow in iadst8.
	const int32x4_t x0_lo = vmull_lane_s16(vget_low_s16(x[0]), c, 0);
	const int32x4_t x0_hi = vmull_lane_s16(vget_high_s16(x[0]), c, 0);
	const int32x4_t x1_lo = vmull_lane_s16(vget_low_s16(x[1]), c, 0);
	const int32x4_t x1_hi = vmull_lane_s16(vget_high_s16(x[1]), c, 0);
	int32x4_t t0[2], t1[2];

	t0[0] = vaddq_s32(x0_lo, x1_lo);
	t0[1] = vaddq_s32(x0_hi, x1_hi);
	t1[0] = vsubq_s32(x0_lo, x1_lo);
	t1[1] = vsubq_s32(x0_hi, x1_hi);
	x[0] = dct_const_round_shift_low_8(t0);
	x[1] = dct_const_round_shift_low_8(t1);
	}

	static INLINE void iadst_half_butterfly_neg_neon(int16x8_t *const x0,
	int16x8_t *const x1,
	const int16x4_t c) {
	// Don't add/sub before multiply, which will overflow in iadst8.
	const int32x4_t x0_lo = vmull_lane_s16(vget_low_s16(*x0), c, 1);
	const int32x4_t x0_hi = vmull_lane_s16(vget_high_s16(*x0), c, 1);
	const int32x4_t x1_lo = vmull_lane_s16(vget_low_s16(*x1), c, 1);
	const int32x4_t x1_hi = vmull_lane_s16(vget_high_s16(*x1), c, 1);
	int32x4_t t0[2], t1[2];

	t0[0] = vaddq_s32(x0_lo, x1_lo);
	t0[1] = vaddq_s32(x0_hi, x1_hi);
	t1[0] = vsubq_s32(x0_lo, x1_lo);
	t1[1] = vsubq_s32(x0_hi, x1_hi);
	*x1 = dct_const_round_shift_low_8(t0);
	*x0 = dct_const_round_shift_low_8(t1);
	}

	static INLINE void iadst_half_butterfly_pos_neon(int16x8_t *const x0,
	int16x8_t *const x1,
	const int16x4_t c) {
	// Don't add/sub before multiply, which will overflow in iadst8.
	const int32x4_t x0_lo = vmull_lane_s16(vget_low_s16(*x0), c, 0);
	const int32x4_t x0_hi = vmull_lane_s16(vget_high_s16(*x0), c, 0);
	const int32x4_t x1_lo = vmull_lane_s16(vget_low_s16(*x1), c, 0);
	const int32x4_t x1_hi = vmull_lane_s16(vget_high_s16(*x1), c, 0);
	int32x4_t t0[2], t1[2];

	t0[0] = vaddq_s32(x0_lo, x1_lo);
	t0[1] = vaddq_s32(x0_hi, x1_hi);
	t1[0] = vsubq_s32(x0_lo, x1_lo);
	t1[1] = vsubq_s32(x0_hi, x1_hi);
	*x1 = dct_const_round_shift_low_8(t0);
	*x0 = dct_const_round_shift_low_8(t1);
	}

	static INLINE void iadst_butterfly_lane_0_1_neon(const int16x8_t in0,
	const int16x8_t in1,
	const int16x4_t c,
	int32x4_t *const s0,
	int32x4_t *const s1) {
	s0[0] = vmull_lane_s16(vget_low_s16(in0), c, 0);
	s0[1] = vmull_lane_s16(vget_high_s16(in0), c, 0);
	s1[0] = vmull_lane_s16(vget_low_s16(in0), c, 1);
	s1[1] = vmull_lane_s16(vget_high_s16(in0), c, 1);

	s0[0] = vmlal_lane_s16(s0[0], vget_low_s16(in1), c, 1);
	s0[1] = vmlal_lane_s16(s0[1], vget_high_s16(in1), c, 1);
	s1[0] = vmlsl_lane_s16(s1[0], vget_low_s16(in1), c, 0);
	s1[1] = vmlsl_lane_s16(s1[1], vget_high_s16(in1), c, 0);
	}

	static INLINE void iadst_butterfly_lane_2_3_neon(const int16x8_t in0,
	const int16x8_t in1,
	const int16x4_t c,
	int32x4_t *const s0,
	int32x4_t *const s1) {
	s0[0] = vmull_lane_s16(vget_low_s16(in0), c, 2);
	s0[1] = vmull_lane_s16(vget_high_s16(in0), c, 2);
	s1[0] = vmull_lane_s16(vget_low_s16(in0), c, 3);
	s1[1] = vmull_lane_s16(vget_high_s16(in0), c, 3);

	s0[0] = vmlal_lane_s16(s0[0], vget_low_s16(in1), c, 3);
	s0[1] = vmlal_lane_s16(s0[1], vget_high_s16(in1), c, 3);
	s1[0] = vmlsl_lane_s16(s1[0], vget_low_s16(in1), c, 2);
	s1[1] = vmlsl_lane_s16(s1[1], vget_high_s16(in1), c, 2);
	}

	static INLINE void iadst_butterfly_lane_1_0_neon(const int16x8_t in0,
	const int16x8_t in1,
	const int16x4_t c,
	int32x4_t *const s0,
	int32x4_t *const s1) {
	s0[0] = vmull_lane_s16(vget_low_s16(in0), c, 1);
	s0[1] = vmull_lane_s16(vget_high_s16(in0), c, 1);
	s1[0] = vmull_lane_s16(vget_low_s16(in0), c, 0);
	s1[1] = vmull_lane_s16(vget_high_s16(in0), c, 0);

	s0[0] = vmlal_lane_s16(s0[0], vget_low_s16(in1), c, 0);
	s0[1] = vmlal_lane_s16(s0[1], vget_high_s16(in1), c, 0);
	s1[0] = vmlsl_lane_s16(s1[0], vget_low_s16(in1), c, 1);
	s1[1] = vmlsl_lane_s16(s1[1], vget_high_s16(in1), c, 1);
	}

	static INLINE void iadst_butterfly_lane_3_2_neon(const int16x8_t in0,
	const int16x8_t in1,
	const int16x4_t c,
	int32x4_t *const s0,
	int32x4_t *const s1) {
	s0[0] = vmull_lane_s16(vget_low_s16(in0), c, 3);
	s0[1] = vmull_lane_s16(vget_high_s16(in0), c, 3);
	s1[0] = vmull_lane_s16(vget_low_s16(in0), c, 2);
	s1[1] = vmull_lane_s16(vget_high_s16(in0), c, 2);

	s0[0] = vmlal_lane_s16(s0[0], vget_low_s16(in1), c, 2);
	s0[1] = vmlal_lane_s16(s0[1], vget_high_s16(in1), c, 2);
	s1[0] = vmlsl_lane_s16(s1[0], vget_low_s16(in1), c, 3);
	s1[1] = vmlsl_lane_s16(s1[1], vget_high_s16(in1), c, 3);
	}

	static INLINE int16x8_t add_dct_const_round_shift_low_8(
	const int32x4_t const in0, const int32x4_t const in1) {
	int32x4_t sum[2];

	sum[0] = vaddq_s32(in0[0], in1[0]);
	sum[1] = vaddq_s32(in0[1], in1[1]);
	return dct_const_round_shift_low_8(sum);
	}

	static INLINE int16x8_t sub_dct_const_round_shift_low_8(
	const int32x4_t const in0, const int32x4_t const in1) {
	int32x4_t sum[2];

	sum[0] = vsubq_s32(in0[0], in1[0]);
	sum[1] = vsubq_s32(in0[1], in1[1]);
	return dct_const_round_shift_low_8(sum);
	}

	static INLINE void iadst8(int16x8_t *const io) {
	const int16x4_t c0 =
	create_s16x4_neon(cospi_2_64, cospi_30_64, cospi_10_64, cospi_22_64);
	const int16x4_t c1 =
	create_s16x4_neon(cospi_18_64, cospi_14_64, cospi_26_64, cospi_6_64);
	const int16x4_t c2 =
	create_s16x4_neon(cospi_16_64, 0, cospi_8_64, cospi_24_64);
	int16x8_t x[8], t[4];
	int32x4_t s0[2], s1[2], s2[2], s3[2], s4[2], s5[2], s6[2], s7[2];

	x[0] = io[7];
	x[1] = io[0];
	x[2] = io[5];
	x[3] = io[2];
	x[4] = io[3];
	x[5] = io[4];
	x[6] = io[1];
	x[7] = io[6];

	// stage 1
	iadst_butterfly_lane_0_1_neon(x[0], x[1], c0, s0, s1);
	iadst_butterfly_lane_2_3_neon(x[2], x[3], c0, s2, s3);
	iadst_butterfly_lane_0_1_neon(x[4], x[5], c1, s4, s5);
	iadst_butterfly_lane_2_3_neon(x[6], x[7], c1, s6, s7);

	x[0] = add_dct_const_round_shift_low_8(s0, s4);
	x[1] = add_dct_const_round_shift_low_8(s1, s5);
	x[2] = add_dct_const_round_shift_low_8(s2, s6);
	x[3] = add_dct_const_round_shift_low_8(s3, s7);
	x[4] = sub_dct_const_round_shift_low_8(s0, s4);
	x[5] = sub_dct_const_round_shift_low_8(s1, s5);
	x[6] = sub_dct_const_round_shift_low_8(s2, s6);
	x[7] = sub_dct_const_round_shift_low_8(s3, s7);

	// stage 2
	t[0] = x[0];
	t[1] = x[1];
	t[2] = x[2];
	t[3] = x[3];
	iadst_butterfly_lane_2_3_neon(x[4], x[5], c2, s4, s5);
	iadst_butterfly_lane_3_2_neon(x[7], x[6], c2, s7, s6);

	x[0] = vaddq_s16(t[0], t[2]);
	x[1] = vaddq_s16(t[1], t[3]);
	x[2] = vsubq_s16(t[0], t[2]);
	x[3] = vsubq_s16(t[1], t[3]);
	x[4] = add_dct_const_round_shift_low_8(s4, s6);
	x[5] = add_dct_const_round_shift_low_8(s5, s7);
	x[6] = sub_dct_const_round_shift_low_8(s4, s6);
	x[7] = sub_dct_const_round_shift_low_8(s5, s7);

	// stage 3
	iadst_half_butterfly_neon(x + 2, c2);
	iadst_half_butterfly_neon(x + 6, c2);

	io[0] = x[0];
	io[1] = vnegq_s16(x[4]);
	io[2] = x[6];
	io[3] = vnegq_s16(x[2]);
	io[4] = x[3];
	io[5] = vnegq_s16(x[7]);
	io[6] = x[5];
	io[7] = vnegq_s16(x[1]);
	}

	void vpx_iadst16x16_256_add_half1d(const void const input, int16_t output,
	void *const dest, const int stride,
	const int highbd_flag);

	typedef void (iht_1d)(const void const input, int16_t *output,
	void *const dest, const int stride,
	const int highbd_flag);

	typedef struct {
	iht_1d cols, rows; // vertical and horizontal
	} iht_2d;

	#endif // VPX_VP9_COMMON_ARM_NEON_VP9_IHT_NEON_H_