/***************************************************************************
Copyright (c) 2013-2019, The OpenBLAS Project
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modification, are permitted provided that the following conditions are
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2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the
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3. Neither the name of the OpenBLAS project nor the names of
its contributors may be used to endorse or promote products
derived from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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*****************************************************************************/

/*
 * Avoid contraction of floating point operations, specifically fused
 * multiply-add, because they can cause unexpected results in complex
 * multiplication.
 */
#if defined(__GNUC__) && !defined(__clang__)
#pragma GCC optimize ("fp-contract=off")
#endif

#if defined(__clang__)
#pragma clang fp contract(off)
#endif

#include "common.h"
#include "vector-common.h"

static void cscal_kernel_16(BLASLONG n, FLOAT da_r, FLOAT da_i, FLOAT *x) {
    vector_float da_r_vec = vec_splats(da_r);
    vector_float da_i_vec = { -da_i, da_i, -da_i, da_i };

    vector_float *x_vec_ptr = (vector_float *)x;

#pragma GCC unroll 16
    for (size_t i = 0; i < n/2; i++) {
	vector_float x_vec = vec_load_hinted(x + i * VLEN_FLOATS);
	vector_float x_swapped = {x_vec[1], x_vec[0], x_vec[3], x_vec[2]};

	x_vec_ptr[i] =  x_vec * da_r_vec + x_swapped * da_i_vec;
    }
}

static void cscal_kernel_16_zero_r(BLASLONG n, FLOAT *alpha, FLOAT *x) {
  __asm__("vlef   %%v0,4(%[alpha]),0\n\t"
    "vlef   %%v0,4(%[alpha]),2\n\t"
    "vflcsb %%v0,%%v0\n\t"
    "vlef   %%v0,4(%[alpha]),1\n\t"
    "vlef   %%v0,4(%[alpha]),3\n\t"
    "srlg %[n],%[n],4\n\t"
    "xgr   %%r1,%%r1\n\t"
    "0:\n\t"
    "pfd 2, 1024(%%r1,%[x])\n\t"
    "vl   %%v16,0(%%r1,%[x])\n\t"
    "vl   %%v17,16(%%r1,%[x])\n\t"
    "vl   %%v18,32(%%r1,%[x])\n\t"
    "vl   %%v19,48(%%r1,%[x])\n\t"
    "vl   %%v20,64(%%r1,%[x])\n\t"
    "vl   %%v21,80(%%r1,%[x])\n\t"
    "vl   %%v22,96(%%r1,%[x])\n\t"
    "vl   %%v23,112(%%r1,%[x])\n\t"
    "verllg   %%v16,%%v16,32\n\t"
    "verllg   %%v17,%%v17,32\n\t"
    "verllg   %%v18,%%v18,32\n\t"
    "verllg   %%v19,%%v19,32\n\t"
    "verllg   %%v20,%%v20,32\n\t"
    "verllg   %%v21,%%v21,32\n\t"
    "verllg   %%v22,%%v22,32\n\t"
    "verllg   %%v23,%%v23,32\n\t"
    "vfmsb %%v16,%%v16,%%v0\n\t"
    "vfmsb %%v17,%%v17,%%v0\n\t"
    "vfmsb %%v18,%%v18,%%v0\n\t"
    "vfmsb %%v19,%%v19,%%v0\n\t"
    "vfmsb %%v20,%%v20,%%v0\n\t"
    "vfmsb %%v21,%%v21,%%v0\n\t"
    "vfmsb %%v22,%%v22,%%v0\n\t"
    "vfmsb %%v23,%%v23,%%v0\n\t"
    "vst %%v16,0(%%r1,%[x])\n\t"
    "vst %%v17,16(%%r1,%[x])\n\t"
    "vst %%v18,32(%%r1,%[x])\n\t"
    "vst %%v19,48(%%r1,%[x])\n\t"
    "vst %%v20,64(%%r1,%[x])\n\t"
    "vst %%v21,80(%%r1,%[x])\n\t"
    "vst %%v22,96(%%r1,%[x])\n\t"
    "vst %%v23,112(%%r1,%[x])\n\t"
    "agfi  %%r1,128\n\t"
    "brctg %[n],0b"
    : "+m"(*(FLOAT (*)[n * 2]) x),[n] "+&r"(n)
    : [x] "a"(x), "m"(*(const FLOAT (*)[2]) alpha),
       [alpha] "a"(alpha)
    : "cc", "r1", "v0", "v16", "v17", "v18", "v19", "v20", "v21", "v22",
       "v23");
}

static void cscal_kernel_16_zero_i(BLASLONG n, FLOAT *alpha, FLOAT *x) {
  __asm__("vlrepf %%v0,0(%[alpha])\n\t"
    "srlg %[n],%[n],4\n\t"
    "xgr   %%r1,%%r1\n\t"
    "0:\n\t"
    "pfd 2, 1024(%%r1,%[x])\n\t"
    "vl   %%v16,0(%%r1,%[x])\n\t"
    "vl   %%v17,16(%%r1,%[x])\n\t"
    "vl   %%v18,32(%%r1,%[x])\n\t"
    "vl   %%v19,48(%%r1,%[x])\n\t"
    "vl   %%v20,64(%%r1,%[x])\n\t"
    "vl   %%v21,80(%%r1,%[x])\n\t"
    "vl   %%v22,96(%%r1,%[x])\n\t"
    "vl   %%v23,112(%%r1,%[x])\n\t"
    "vfmsb %%v16,%%v16,%%v0\n\t"
    "vfmsb %%v17,%%v17,%%v0\n\t"
    "vfmsb %%v18,%%v18,%%v0\n\t"
    "vfmsb %%v19,%%v19,%%v0\n\t"
    "vfmsb %%v20,%%v20,%%v0\n\t"
    "vfmsb %%v21,%%v21,%%v0\n\t"
    "vfmsb %%v22,%%v22,%%v0\n\t"
    "vfmsb %%v23,%%v23,%%v0\n\t"
    "vst %%v16,0(%%r1,%[x])\n\t"
    "vst %%v17,16(%%r1,%[x])\n\t"
    "vst %%v18,32(%%r1,%[x])\n\t"
    "vst %%v19,48(%%r1,%[x])\n\t"
    "vst %%v20,64(%%r1,%[x])\n\t"
    "vst %%v21,80(%%r1,%[x])\n\t"
    "vst %%v22,96(%%r1,%[x])\n\t"
    "vst %%v23,112(%%r1,%[x])\n\t"
    "agfi  %%r1,128\n\t"
    "brctg %[n],0b"
    : "+m"(*(FLOAT (*)[n * 2]) x),[n] "+&r"(n)
    : [x] "a"(x), "m"(*(const FLOAT (*)[2]) alpha),
       [alpha] "a"(alpha)
    : "cc", "r1", "v0", "v16", "v17", "v18", "v19", "v20", "v21", "v22",
       "v23");
}

static void cscal_kernel_16_zero(BLASLONG n, FLOAT *x) {
  __asm__("vzero %%v0\n\t"
    "srlg %[n],%[n],4\n\t"
    "xgr   %%r1,%%r1\n\t"
    "0:\n\t"
    "pfd 2, 1024(%%r1,%[x])\n\t"
    "vst  %%v0,0(%%r1,%[x])\n\t"
    "vst  %%v0,16(%%r1,%[x])\n\t"
    "vst  %%v0,32(%%r1,%[x])\n\t"
    "vst  %%v0,48(%%r1,%[x])\n\t"
    "vst  %%v0,64(%%r1,%[x])\n\t"
    "vst  %%v0,80(%%r1,%[x])\n\t"
    "vst  %%v0,96(%%r1,%[x])\n\t"
    "vst  %%v0,112(%%r1,%[x])\n\t"
    "agfi  %%r1,128\n\t"
    "brctg %[n],0b"
    : "=m"(*(FLOAT (*)[n * 2]) x),[n] "+&r"(n)
    : [x] "a"(x)
    : "cc", "r1", "v0");
}

static void cscal_kernel_inc_8(BLASLONG n, FLOAT da_r, FLOAT da_i, FLOAT *x,
                               BLASLONG inc_x) {
  BLASLONG i;
  BLASLONG inc_x2 = 2 * inc_x;
  BLASLONG inc_x3 = inc_x2 + inc_x;
  FLOAT t0, t1, t2, t3;

  for (i = 0; i < n; i += 4) {
    t0 = da_r * x[0] - da_i * x[1];
    t1 = da_r * x[inc_x] - da_i * x[inc_x + 1];
    t2 = da_r * x[inc_x2] - da_i * x[inc_x2 + 1];
    t3 = da_r * x[inc_x3] - da_i * x[inc_x3 + 1];

    x[1] = da_i * x[0] + da_r * x[1];
    x[inc_x + 1] = da_i * x[inc_x] + da_r * x[inc_x + 1];
    x[inc_x2 + 1] = da_i * x[inc_x2] + da_r * x[inc_x2 + 1];
    x[inc_x3 + 1] = da_i * x[inc_x3] + da_r * x[inc_x3 + 1];

    x[0] = t0;
    x[inc_x] = t1;
    x[inc_x2] = t2;
    x[inc_x3] = t3;

    x += 4 * inc_x;
  }
}

int CNAME(BLASLONG n, BLASLONG dummy0, BLASLONG dummy1, FLOAT da_r, FLOAT da_i,
          FLOAT *x, BLASLONG inc_x, FLOAT *y, BLASLONG inc_y, FLOAT *dummy,
          BLASLONG dummy2) {
  BLASLONG i = 0, j = 0;
  FLOAT temp0;
  FLOAT temp1;
  FLOAT alpha[2] __attribute__ ((aligned(16)));

  if (inc_x != 1) {
    inc_x <<= 1;

    if (da_r == 0.0) {

      BLASLONG n1 = n & -2;

      if (da_i == 0.0) {

        while (j < n1) {

          x[i] = 0.0;
          x[i + 1] = 0.0;
          x[i + inc_x] = 0.0;
          x[i + 1 + inc_x] = 0.0;
          i += 2 * inc_x;
          j += 2;

        }

        while (j < n) {

          x[i] = 0.0;
          x[i + 1] = 0.0;
          i += inc_x;
          j++;

        }

      } else {

        while (j < n1) {

          temp0 = -da_i * x[i + 1];
          x[i + 1] = da_i * x[i];
          x[i] = temp0;
          temp1 = -da_i * x[i + 1 + inc_x];
          x[i + 1 + inc_x] = da_i * x[i + inc_x];
          x[i + inc_x] = temp1;
          i += 2 * inc_x;
          j += 2;

        }

        while (j < n) {

          temp0 = -da_i * x[i + 1];
          x[i + 1] = da_i * x[i];
          x[i] = temp0;
          i += inc_x;
          j++;

        }

      }

    } else {

      if (da_i == 0.0) {
        BLASLONG n1 = n & -2;

        while (j < n1) {

          temp0 = da_r * x[i];
          x[i + 1] = da_r * x[i + 1];
          x[i] = temp0;
          temp1 = da_r * x[i + inc_x];
          x[i + 1 + inc_x] = da_r * x[i + 1 + inc_x];
          x[i + inc_x] = temp1;
          i += 2 * inc_x;
          j += 2;

        }

        while (j < n) {

          temp0 = da_r * x[i];
          x[i + 1] = da_r * x[i + 1];
          x[i] = temp0;
          i += inc_x;
          j++;

        }

      } else {

        BLASLONG n1 = n & -8;
        if (n1 > 0) {
          cscal_kernel_inc_8(n1, da_r, da_i, x, inc_x);
          j = n1;
          i = n1 * inc_x;
        }

        while (j < n) {

          temp0 = da_r * x[i] - da_i * x[i + 1];
          x[i + 1] = da_r * x[i + 1] + da_i * x[i];
          x[i] = temp0;
          i += inc_x;
          j++;

        }

      }

    }

    return (0);
  }

  BLASLONG n1 = n & -16;
  if (n1 > 0) {

    alpha[0] = da_r;
    alpha[1] = da_i;

    if (da_r == 0.0)
      if (da_i == 0)
        cscal_kernel_16_zero(n1, x);
      else
        cscal_kernel_16_zero_r(n1, alpha, x);
    else if (da_i == 0)
      cscal_kernel_16_zero_i(n1, alpha, x);
    else
      cscal_kernel_16(n1, da_r, da_i, x);

    i = n1 << 1;
    j = n1;
  }

  if (da_r == 0.0) {

    if (da_i == 0.0) {

      while (j < n) {

        x[i] = 0.0;
        x[i + 1] = 0.0;
        i += 2;
        j++;

      }

    } else {

      while (j < n) {

        temp0 = -da_i * x[i + 1];
        x[i + 1] = da_i * x[i];
        x[i] = temp0;
        i += 2;
        j++;

      }

    }

  } else {

    if (da_i == 0.0) {

      while (j < n) {

        temp0 = da_r * x[i];
        x[i + 1] = da_r * x[i + 1];
        x[i] = temp0;
        i += 2;
        j++;

      }

    } else {

      while (j < n) {

        temp0 = da_r * x[i] - da_i * x[i + 1];
        x[i + 1] = da_r * x[i + 1] + da_i * x[i];
        x[i] = temp0;
        i += 2;
        j++;

      }

    }

  }

  return (0);
}
