// Auto-generated file. Do not edit!
//   Template: src/f32-sigmoid/scalar-lut2048-p1-div.c.in
//   Generator: tools/xngen
//
// Copyright 2019 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 <math.h>

#include <xnnpack/common.h>
#include <xnnpack/vunary.h>

#include <fp16/bitcasts.h>


// Note redefine as uint32[] to avoid redundant bitcasts.
extern XNN_INTERNAL const uint32_t xnn_table_exp2minus_k_over_2048[2048];

void xnn_f32_sigmoid_ukernel__scalar_lut2048_p1_div_x1(
    size_t n,
    const float* x,
    float* y,
    const void* params)
{
  assert(n % sizeof(float) == 0);

  const float vmagic_bias = 0x1.800000p12f;
  const float vminus_log2e = -0x1.715476p0f;
  const uint32_t vindex_mask = UINT32_C(0x7FF);
  const float vln2_hi = 0x1.600000p-1f;
  const float vln2_lo = 0x1.7217F8p-8f;
  const float vc1 = -0x1.FFFFFEp-1f;
  const float vone = 1.0f;
  const float vdenorm_cutoff = 0x1.5D589Ep+6f;

  do {
    const float vx = *x++;

    const float vz = fabsf(vx);

    float vn = vz * vminus_log2e + vmagic_bias;
    const uint32_t ve = fp32_to_bits(vn) << 12;
    const uint32_t vidx = fp32_to_bits(vn) & vindex_mask;
    const float vs = fp32_from_bits(xnn_table_exp2minus_k_over_2048[vidx] + ve);
    vn -= vmagic_bias;

    float vt = vn * vln2_hi + vz;
    vt = vn * vln2_lo + vt;

    const float vp = vt * vc1;
    const float vy = vp * vs + vs;

    const float vd = vy + vone;
    float vf = vy / vd;
    if XNN_UNPREDICTABLE(vz > vdenorm_cutoff) {
      vf = 0.0f;
    }
    if XNN_UNPREDICTABLE(vx > 0.0f) {
      vf = vone - vf;
    }

    *y++ = vf;

    n -= sizeof(float);
  } while (n != 0);
}