// Auto-generated file. Do not edit!
//   Template: src/cs16-bfly4/scalar.c.in
//   Generator: tools/xngen
//
// Copyright 2022 Google LLC
//
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree.

#include <assert.h>
#include <stddef.h>
#include <stdint.h>

#include <xnnpack/math.h>
#include <xnnpack/fft.h>


void xnn_cs16_bfly4_ukernel__scalar_x2(
    size_t batch,
    size_t samples,
    int16_t* data,
    const int16_t* twiddle,
    size_t stride)
{
  assert(batch != 0);
  assert(samples != 0);
  assert(samples % (sizeof(int16_t) * 2) == 0);
  assert(data != NULL);
  assert(stride != 0);
  assert(twiddle != NULL);

  int16_t* data3 = data;

  do {
    int16_t* data0 = data3;
    int16_t* data1 = (int16_t*) ((uintptr_t) data0 + samples);
    int16_t* data2 = (int16_t*) ((uintptr_t) data1 + samples);
    data3 = (int16_t*) ((uintptr_t) data2 + samples);

    const int16_t* tw1 = twiddle;
    const int16_t* tw2 = twiddle;
    const int16_t* tw3 = twiddle;
    tw1 = (const int16_t*) ((uintptr_t) tw1 + stride);
    tw2 = (const int16_t*) ((uintptr_t) tw2 + stride * 2);
    tw3 = (const int16_t*) ((uintptr_t) tw3 + stride * 3);

    size_t s = samples - sizeof(int16_t) * 2;

    // First sample skips twiddle.
    // Same code as samples=1 but supports stride
    {
      int32_t vout0r = (int32_t) data0[0];
      int32_t vout0i = (int32_t) data0[1];
      int32_t vout1r = (int32_t) data1[0];
      int32_t vout1i = (int32_t) data1[1];
      int32_t vout2r = (int32_t) data2[0];
      int32_t vout2i = (int32_t) data2[1];
      int32_t vout3r = (int32_t) data3[0];
      int32_t vout3i = (int32_t) data3[1];

      // Note 32767 / 4 = 8191.  Should be 8192.
      vout0r = math_asr_s32(vout0r * 8191 + 16384, 15);
      vout0i = math_asr_s32(vout0i * 8191 + 16384, 15);
      vout1r = math_asr_s32(vout1r * 8191 + 16384, 15);
      vout1i = math_asr_s32(vout1i * 8191 + 16384, 15);
      vout2r = math_asr_s32(vout2r * 8191 + 16384, 15);
      vout2i = math_asr_s32(vout2i * 8191 + 16384, 15);
      vout3r = math_asr_s32(vout3r * 8191 + 16384, 15);
      vout3i = math_asr_s32(vout3i * 8191 + 16384, 15);

      const int32_t vtmp5r = vout0r - vout2r;
      const int32_t vtmp5i = vout0i - vout2i;
      vout0r += vout2r;
      vout0i += vout2i;
      const int32_t vtmp3r = vout1r + vout3r;
      const int32_t vtmp3i = vout1i + vout3i;
      const int32_t vtmp4r = vout1i - vout3i;
      const int32_t vtmp4i = -(vout1r - vout3r);  // swap r,i and neg i
      vout2r = vout0r - vtmp3r;
      vout2i = vout0i - vtmp3i;

      vout0r += vtmp3r;
      vout0i += vtmp3i;

      vout1r = vtmp5r + vtmp4r;
      vout1i = vtmp5i + vtmp4i;
      vout3r = vtmp5r - vtmp4r;
      vout3i = vtmp5i - vtmp4i;

      data0[0] = (int16_t) vout0r;
      data0[1] = (int16_t) vout0i;
      data1[0] = (int16_t) vout1r;
      data1[1] = (int16_t) vout1i;
      data2[0] = (int16_t) vout2r;
      data2[1] = (int16_t) vout2i;
      data3[0] = (int16_t) vout3r;
      data3[1] = (int16_t) vout3i;
      data0 += 2;
      data1 += 2;
      data2 += 2;
      data3 += 2;
    }

    for (; s >= 2 * sizeof(int16_t) * 2; s -= 2 * sizeof(int16_t) * 2) {
      int32_t vout0r0 = (int32_t) data0[0];
      int32_t vout0i0 = (int32_t) data0[1];
      int32_t vout0r1 = (int32_t) data0[2];
      int32_t vout0i1 = (int32_t) data0[3];
      int32_t vout1r0 = (int32_t) data1[0];
      int32_t vout1i0 = (int32_t) data1[1];
      int32_t vout1r1 = (int32_t) data1[2];
      int32_t vout1i1 = (int32_t) data1[3];
      int32_t vout2r0 = (int32_t) data2[0];
      int32_t vout2i0 = (int32_t) data2[1];
      int32_t vout2r1 = (int32_t) data2[2];
      int32_t vout2i1 = (int32_t) data2[3];
      int32_t vout3r0 = (int32_t) data3[0];
      int32_t vout3i0 = (int32_t) data3[1];
      int32_t vout3r1 = (int32_t) data3[2];
      int32_t vout3i1 = (int32_t) data3[3];

      const int32_t vtw1r0 = (const int32_t) tw1[0];
      const int32_t vtw1i0 = (const int32_t) tw1[1];
      tw1 = (const int16_t*) ((uintptr_t) tw1 + stride);
      const int32_t vtw1r1 = (const int32_t) tw1[0];
      const int32_t vtw1i1 = (const int32_t) tw1[1];
      tw1 = (const int16_t*) ((uintptr_t) tw1 + stride);
      const int32_t vtw2r0 = (const int32_t) tw2[0];
      const int32_t vtw2i0 = (const int32_t) tw2[1];
      tw2 = (const int16_t*) ((uintptr_t) tw2 + stride * 2);
      const int32_t vtw2r1 = (const int32_t) tw2[0];
      const int32_t vtw2i1 = (const int32_t) tw2[1];
      tw2 = (const int16_t*) ((uintptr_t) tw2 + stride * 2);
      const int32_t vtw3r0 = (const int32_t) tw3[0];
      const int32_t vtw3i0 = (const int32_t) tw3[1];
      tw3 = (const int16_t*) ((uintptr_t) tw3 + stride * 3);
      const int32_t vtw3r1 = (const int32_t) tw3[0];
      const int32_t vtw3i1 = (const int32_t) tw3[1];
      tw3 = (const int16_t*) ((uintptr_t) tw3 + stride * 3);

      // Note 32767 / 4 = 8191.  Should be 8192.
      vout0r0 = math_asr_s32(vout0r0 * 8191 + 16384, 15);
      vout0i0 = math_asr_s32(vout0i0 * 8191 + 16384, 15);
      vout0r1 = math_asr_s32(vout0r1 * 8191 + 16384, 15);
      vout0i1 = math_asr_s32(vout0i1 * 8191 + 16384, 15);
      vout1r0 = math_asr_s32(vout1r0 * 8191 + 16384, 15);
      vout1i0 = math_asr_s32(vout1i0 * 8191 + 16384, 15);
      vout1r1 = math_asr_s32(vout1r1 * 8191 + 16384, 15);
      vout1i1 = math_asr_s32(vout1i1 * 8191 + 16384, 15);
      vout2r0 = math_asr_s32(vout2r0 * 8191 + 16384, 15);
      vout2i0 = math_asr_s32(vout2i0 * 8191 + 16384, 15);
      vout2r1 = math_asr_s32(vout2r1 * 8191 + 16384, 15);
      vout2i1 = math_asr_s32(vout2i1 * 8191 + 16384, 15);
      vout3r0 = math_asr_s32(vout3r0 * 8191 + 16384, 15);
      vout3i0 = math_asr_s32(vout3i0 * 8191 + 16384, 15);
      vout3r1 = math_asr_s32(vout3r1 * 8191 + 16384, 15);
      vout3i1 = math_asr_s32(vout3i1 * 8191 + 16384, 15);

      const int32_t vtmp0r0 = math_asr_s32(vout1r0 * vtw1r0 - vout1i0 * vtw1i0 + 16384, 15);
      const int32_t vtmp0i0 = math_asr_s32(vout1r0 * vtw1i0 + vout1i0 * vtw1r0 + 16384, 15);
      const int32_t vtmp0r1 = math_asr_s32(vout1r1 * vtw1r1 - vout1i1 * vtw1i1 + 16384, 15);
      const int32_t vtmp0i1 = math_asr_s32(vout1r1 * vtw1i1 + vout1i1 * vtw1r1 + 16384, 15);
      const int32_t vtmp1r0 = math_asr_s32(vout2r0 * vtw2r0 - vout2i0 * vtw2i0 + 16384, 15);
      const int32_t vtmp1i0 = math_asr_s32(vout2r0 * vtw2i0 + vout2i0 * vtw2r0 + 16384, 15);
      const int32_t vtmp1r1 = math_asr_s32(vout2r1 * vtw2r1 - vout2i1 * vtw2i1 + 16384, 15);
      const int32_t vtmp1i1 = math_asr_s32(vout2r1 * vtw2i1 + vout2i1 * vtw2r1 + 16384, 15);
      const int32_t vtmp2r0 = math_asr_s32(vout3r0 * vtw3r0 - vout3i0 * vtw3i0 + 16384, 15);
      const int32_t vtmp2i0 = math_asr_s32(vout3r0 * vtw3i0 + vout3i0 * vtw3r0 + 16384, 15);
      const int32_t vtmp2r1 = math_asr_s32(vout3r1 * vtw3r1 - vout3i1 * vtw3i1 + 16384, 15);
      const int32_t vtmp2i1 = math_asr_s32(vout3r1 * vtw3i1 + vout3i1 * vtw3r1 + 16384, 15);

      const int32_t vtmp5r0 = vout0r0 - vtmp1r0;
      const int32_t vtmp5i0 = vout0i0 - vtmp1i0;
      const int32_t vtmp5r1 = vout0r1 - vtmp1r1;
      const int32_t vtmp5i1 = vout0i1 - vtmp1i1;
      vout0r0 += vtmp1r0;
      vout0i0 += vtmp1i0;
      vout0r1 += vtmp1r1;
      vout0i1 += vtmp1i1;
      const int32_t vtmp3r0 = vtmp0r0 + vtmp2r0;
      const int32_t vtmp3i0 = vtmp0i0 + vtmp2i0;
      const int32_t vtmp3r1 = vtmp0r1 + vtmp2r1;
      const int32_t vtmp3i1 = vtmp0i1 + vtmp2i1;
      const int32_t vtmp4r0 = vtmp0i0 - vtmp2i0;
      const int32_t vtmp4i0 = -(vtmp0r0 - vtmp2r0);  // swap r,i and neg i
      const int32_t vtmp4r1 = vtmp0i1 - vtmp2i1;
      const int32_t vtmp4i1 = -(vtmp0r1 - vtmp2r1);  // swap r,i and neg i
      vout2r0 = vout0r0 - vtmp3r0;
      vout2i0 = vout0i0 - vtmp3i0;
      vout2r1 = vout0r1 - vtmp3r1;
      vout2i1 = vout0i1 - vtmp3i1;
      vout0r0 += vtmp3r0;
      vout0i0 += vtmp3i0;
      vout0r1 += vtmp3r1;
      vout0i1 += vtmp3i1;
      vout1r0 = vtmp5r0 + vtmp4r0;
      vout1i0 = vtmp5i0 + vtmp4i0;
      vout1r1 = vtmp5r1 + vtmp4r1;
      vout1i1 = vtmp5i1 + vtmp4i1;
      vout3r0 = vtmp5r0 - vtmp4r0;
      vout3i0 = vtmp5i0 - vtmp4i0;
      vout3r1 = vtmp5r1 - vtmp4r1;
      vout3i1 = vtmp5i1 - vtmp4i1;

      data0[0] = (int16_t) vout0r0;
      data0[1] = (int16_t) vout0i0;
      data0[2] = (int16_t) vout0r1;
      data0[3] = (int16_t) vout0i1;
      data0 += 2 * 2;
      data1[0] = (int16_t) vout1r0;
      data1[1] = (int16_t) vout1i0;
      data1[2] = (int16_t) vout1r1;
      data1[3] = (int16_t) vout1i1;
      data1 += 2 * 2;
      data2[0] = (int16_t) vout2r0;
      data2[1] = (int16_t) vout2i0;
      data2[2] = (int16_t) vout2r1;
      data2[3] = (int16_t) vout2i1;
      data2 += 2 * 2;
      data3[0] = (int16_t) vout3r0;
      data3[1] = (int16_t) vout3i0;
      data3[2] = (int16_t) vout3r1;
      data3[3] = (int16_t) vout3i1;
      data3 += 2 * 2;
    }
    if XNN_UNLIKELY(s != 0) {
      do {
        int32_t vout0r = (int32_t) data0[0];
        int32_t vout0i = (int32_t) data0[1];
        int32_t vout1r = (int32_t) data1[0];
        int32_t vout1i = (int32_t) data1[1];
        int32_t vout2r = (int32_t) data2[0];
        int32_t vout2i = (int32_t) data2[1];
        int32_t vout3r = (int32_t) data3[0];
        int32_t vout3i = (int32_t) data3[1];

        const int32_t vtw1r = (const int32_t) tw1[0];
        const int32_t vtw1i = (const int32_t) tw1[1];
        const int32_t vtw2r = (const int32_t) tw2[0];
        const int32_t vtw2i = (const int32_t) tw2[1];
        const int32_t vtw3r = (const int32_t) tw3[0];
        const int32_t vtw3i = (const int32_t) tw3[1];
        tw1 = (const int16_t*) ((uintptr_t) tw1 + stride);
        tw2 = (const int16_t*) ((uintptr_t) tw2 + stride * 2);
        tw3 = (const int16_t*) ((uintptr_t) tw3 + stride * 3);

        // Note 32767 / 4 = 8191.  Should be 8192.
        vout0r = math_asr_s32(vout0r * 8191 + 16384, 15);
        vout0i = math_asr_s32(vout0i * 8191 + 16384, 15);
        vout1r = math_asr_s32(vout1r * 8191 + 16384, 15);
        vout1i = math_asr_s32(vout1i * 8191 + 16384, 15);
        vout2r = math_asr_s32(vout2r * 8191 + 16384, 15);
        vout2i = math_asr_s32(vout2i * 8191 + 16384, 15);
        vout3r = math_asr_s32(vout3r * 8191 + 16384, 15);
        vout3i = math_asr_s32(vout3i * 8191 + 16384, 15);

        const int32_t vtmp0r = math_asr_s32(vout1r * vtw1r - vout1i * vtw1i + 16384, 15);
        const int32_t vtmp0i = math_asr_s32(vout1r * vtw1i + vout1i * vtw1r + 16384, 15);
        const int32_t vtmp1r = math_asr_s32(vout2r * vtw2r - vout2i * vtw2i + 16384, 15);
        const int32_t vtmp1i = math_asr_s32(vout2r * vtw2i + vout2i * vtw2r + 16384, 15);
        const int32_t vtmp2r = math_asr_s32(vout3r * vtw3r - vout3i * vtw3i + 16384, 15);
        const int32_t vtmp2i = math_asr_s32(vout3r * vtw3i + vout3i * vtw3r + 16384, 15);

        const int32_t vtmp5r = vout0r - vtmp1r;
        const int32_t vtmp5i = vout0i - vtmp1i;
        vout0r += vtmp1r;
        vout0i += vtmp1i;
        const int32_t vtmp3r = vtmp0r + vtmp2r;
        const int32_t vtmp3i = vtmp0i + vtmp2i;
        const int32_t vtmp4r = vtmp0i - vtmp2i;
        const int32_t vtmp4i = -(vtmp0r - vtmp2r);  // swap r,i and neg i
        vout2r = vout0r - vtmp3r;
        vout2i = vout0i - vtmp3i;

        vout0r += vtmp3r;
        vout0i += vtmp3i;

        vout1r = vtmp5r + vtmp4r;
        vout1i = vtmp5i + vtmp4i;
        vout3r = vtmp5r - vtmp4r;
        vout3i = vtmp5i - vtmp4i;

        data0[0] = (int16_t) vout0r;
        data0[1] = (int16_t) vout0i;
        data1[0] = (int16_t) vout1r;
        data1[1] = (int16_t) vout1i;
        data2[0] = (int16_t) vout2r;
        data2[1] = (int16_t) vout2i;
        data3[0] = (int16_t) vout3r;
        data3[1] = (int16_t) vout3i;
        data0 += 2;
        data1 += 2;
        data2 += 2;
        data3 += 2;

        s -= sizeof(int16_t) * 2;
      } while (s != 0);
    }
  } while (--batch != 0);
}