/* -*- c++ -*- */
/*
 * Copyright 2012, 2014 Free Software Foundation, Inc.
 *
 * This file is part of VOLK
 *
 * SPDX-License-Identifier: GPL-3.0-or-later
 */

/*!
 * \page volk_16i_x4_quad_max_star_16i
 *
 * \b Overview
 *
 * <FIXME>
 *
 * <b>Dispatcher Prototype</b>
 * \code
 * void volk_16i_x4_quad_max_star_16i(short* target, short* src0, short* src1, short*
 * src2, short* src3, unsigned int num_points) \endcode
 *
 * \b Inputs
 * \li src0: The input vector 0.
 * \li src1: The input vector 1.
 * \li src2: The input vector 2.
 * \li src3: The input vector 3.
 * \li num_points: The number of data points.
 *
 * \b Outputs
 * \li target: The output value.
 *
 * \b Example
 * \code
 * int N = 10000;
 *
 * volk_16i_x4_quad_max_star_16i();
 *
 * volk_free(x);
 * \endcode
 */

#ifndef INCLUDED_volk_16i_x4_quad_max_star_16i_a_H
#define INCLUDED_volk_16i_x4_quad_max_star_16i_a_H

#include <inttypes.h>
#include <stdio.h>

#ifdef LV_HAVE_SSE2

#include <emmintrin.h>

static inline void volk_16i_x4_quad_max_star_16i_a_sse2(short* target,
                                                        short* src0,
                                                        short* src1,
                                                        short* src2,
                                                        short* src3,
                                                        unsigned int num_points)
{
    const unsigned int num_bytes = num_points * 2;

    int i = 0;

    int bound = (num_bytes >> 4);
    int bound_copy = bound;
    int leftovers = (num_bytes >> 1) & 7;

    __m128i *p_target, *p_src0, *p_src1, *p_src2, *p_src3;
    p_target = (__m128i*)target;
    p_src0 = (__m128i*)src0;
    p_src1 = (__m128i*)src1;
    p_src2 = (__m128i*)src2;
    p_src3 = (__m128i*)src3;

    __m128i xmm1, xmm2, xmm3, xmm4, xmm5, xmm6, xmm7, xmm8;

    while (bound_copy > 0) {
        xmm1 = _mm_load_si128(p_src0);
        xmm2 = _mm_load_si128(p_src1);
        xmm3 = _mm_load_si128(p_src2);
        xmm4 = _mm_load_si128(p_src3);

        xmm5 = _mm_setzero_si128();
        xmm6 = _mm_setzero_si128();
        xmm7 = xmm1;
        xmm8 = xmm3;

        xmm1 = _mm_sub_epi16(xmm2, xmm1);

        xmm3 = _mm_sub_epi16(xmm4, xmm3);

        xmm5 = _mm_cmpgt_epi16(xmm1, xmm5);
        xmm6 = _mm_cmpgt_epi16(xmm3, xmm6);

        xmm2 = _mm_and_si128(xmm5, xmm2);
        xmm4 = _mm_and_si128(xmm6, xmm4);
        xmm5 = _mm_andnot_si128(xmm5, xmm7);
        xmm6 = _mm_andnot_si128(xmm6, xmm8);

        xmm5 = _mm_add_epi16(xmm2, xmm5);
        xmm6 = _mm_add_epi16(xmm4, xmm6);

        xmm1 = _mm_xor_si128(xmm1, xmm1);
        xmm2 = xmm5;
        xmm5 = _mm_sub_epi16(xmm6, xmm5);
        p_src0 += 1;
        bound_copy -= 1;

        xmm1 = _mm_cmpgt_epi16(xmm5, xmm1);
        p_src1 += 1;

        xmm6 = _mm_and_si128(xmm1, xmm6);

        xmm1 = _mm_andnot_si128(xmm1, xmm2);
        p_src2 += 1;

        xmm1 = _mm_add_epi16(xmm6, xmm1);
        p_src3 += 1;

        _mm_store_si128(p_target, xmm1);
        p_target += 1;
    }


    /*__VOLK_ASM __VOLK_VOLATILE
      (
      "volk_16i_x4_quad_max_star_16i_a_sse2_L1:\n\t"
      "cmp $0, %[bound]\n\t"
      "je volk_16i_x4_quad_max_star_16i_a_sse2_END\n\t"

      "movaps (%[src0]), %%xmm1\n\t"
      "movaps (%[src1]), %%xmm2\n\t"
      "movaps (%[src2]), %%xmm3\n\t"
      "movaps (%[src3]), %%xmm4\n\t"

      "pxor %%xmm5, %%xmm5\n\t"
      "pxor %%xmm6, %%xmm6\n\t"
      "movaps %%xmm1, %%xmm7\n\t"
      "movaps %%xmm3, %%xmm8\n\t"
      "psubw %%xmm2, %%xmm1\n\t"
      "psubw %%xmm4, %%xmm3\n\t"

      "pcmpgtw %%xmm1, %%xmm5\n\t"
      "pcmpgtw %%xmm3, %%xmm6\n\t"

      "pand %%xmm5, %%xmm2\n\t"
      "pand %%xmm6, %%xmm4\n\t"
      "pandn %%xmm7, %%xmm5\n\t"
      "pandn %%xmm8, %%xmm6\n\t"

      "paddw %%xmm2, %%xmm5\n\t"
      "paddw %%xmm4, %%xmm6\n\t"

      "pxor %%xmm1, %%xmm1\n\t"
      "movaps %%xmm5, %%xmm2\n\t"

      "psubw %%xmm6, %%xmm5\n\t"
      "add $16, %[src0]\n\t"
      "add $-1, %[bound]\n\t"

      "pcmpgtw %%xmm5, %%xmm1\n\t"
      "add $16, %[src1]\n\t"

      "pand %%xmm1, %%xmm6\n\t"

      "pandn %%xmm2, %%xmm1\n\t"
      "add $16, %[src2]\n\t"

      "paddw %%xmm6, %%xmm1\n\t"
      "add $16, %[src3]\n\t"

      "movaps %%xmm1, (%[target])\n\t"
      "addw $16, %[target]\n\t"
      "jmp volk_16i_x4_quad_max_star_16i_a_sse2_L1\n\t"

      "volk_16i_x4_quad_max_star_16i_a_sse2_END:\n\t"
      :
      :[bound]"r"(bound), [src0]"r"(src0), [src1]"r"(src1), [src2]"r"(src2),
      [src3]"r"(src3), [target]"r"(target)
      :
      );
    */

    short temp0 = 0;
    short temp1 = 0;
    for (i = bound * 8; i < (bound * 8) + leftovers; ++i) {
        temp0 = ((short)(src0[i] - src1[i]) > 0) ? src0[i] : src1[i];
        temp1 = ((short)(src2[i] - src3[i]) > 0) ? src2[i] : src3[i];
        target[i] = ((short)(temp0 - temp1) > 0) ? temp0 : temp1;
    }
    return;
}

#endif /*LV_HAVE_SSE2*/

#ifdef LV_HAVE_NEON

#include <arm_neon.h>

static inline void volk_16i_x4_quad_max_star_16i_neon(short* target,
                                                      short* src0,
                                                      short* src1,
                                                      short* src2,
                                                      short* src3,
                                                      unsigned int num_points)
{
    const unsigned int eighth_points = num_points / 8;
    unsigned i;

    int16x8_t src0_vec, src1_vec, src2_vec, src3_vec;
    int16x8_t diff12, diff34;
    int16x8_t comp0, comp1, comp2, comp3;
    int16x8_t result1_vec, result2_vec;
    int16x8_t zeros;
    zeros = vdupq_n_s16(0);
    for (i = 0; i < eighth_points; ++i) {
        src0_vec = vld1q_s16(src0);
        src1_vec = vld1q_s16(src1);
        src2_vec = vld1q_s16(src2);
        src3_vec = vld1q_s16(src3);
        diff12 = vsubq_s16(src0_vec, src1_vec);
        diff34 = vsubq_s16(src2_vec, src3_vec);
        comp0 = (int16x8_t)vcgeq_s16(diff12, zeros);
        comp1 = (int16x8_t)vcltq_s16(diff12, zeros);
        comp2 = (int16x8_t)vcgeq_s16(diff34, zeros);
        comp3 = (int16x8_t)vcltq_s16(diff34, zeros);
        comp0 = vandq_s16(src0_vec, comp0);
        comp1 = vandq_s16(src1_vec, comp1);
        comp2 = vandq_s16(src2_vec, comp2);
        comp3 = vandq_s16(src3_vec, comp3);

        result1_vec = vaddq_s16(comp0, comp1);
        result2_vec = vaddq_s16(comp2, comp3);

        diff12 = vsubq_s16(result1_vec, result2_vec);
        comp0 = (int16x8_t)vcgeq_s16(diff12, zeros);
        comp1 = (int16x8_t)vcltq_s16(diff12, zeros);
        comp0 = vandq_s16(result1_vec, comp0);
        comp1 = vandq_s16(result2_vec, comp1);
        result1_vec = vaddq_s16(comp0, comp1);
        vst1q_s16(target, result1_vec);
        src0 += 8;
        src1 += 8;
        src2 += 8;
        src3 += 8;
        target += 8;
    }

    short temp0 = 0;
    short temp1 = 0;
    for (i = eighth_points * 8; i < num_points; ++i) {
        temp0 = ((short)(*src0 - *src1) > 0) ? *src0 : *src1;
        temp1 = ((short)(*src2 - *src3) > 0) ? *src2 : *src3;
        *target++ = ((short)(temp0 - temp1) > 0) ? temp0 : temp1;
        src0++;
        src1++;
        src2++;
        src3++;
    }
}
#endif /* LV_HAVE_NEON */


#ifdef LV_HAVE_GENERIC
static inline void volk_16i_x4_quad_max_star_16i_generic(short* target,
                                                         short* src0,
                                                         short* src1,
                                                         short* src2,
                                                         short* src3,
                                                         unsigned int num_points)
{
    const unsigned int num_bytes = num_points * 2;

    int i = 0;

    int bound = num_bytes >> 1;

    short temp0 = 0;
    short temp1 = 0;
    for (i = 0; i < bound; ++i) {
        temp0 = ((short)(src0[i] - src1[i]) > 0) ? src0[i] : src1[i];
        temp1 = ((short)(src2[i] - src3[i]) > 0) ? src2[i] : src3[i];
        target[i] = ((short)(temp0 - temp1) > 0) ? temp0 : temp1;
    }
}

#endif /*LV_HAVE_GENERIC*/

#endif /*INCLUDED_volk_16i_x4_quad_max_star_16i_a_H*/
