/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree.
 */

#include <executorch/backends/cadence/fusion_g3/operators/operators.h>

#include <xa_nnlib_kernels_api.h>

#include <executorch/backends/cadence/fusion_g3/operators/xt_macros.h>
#include <executorch/kernels/portable/cpu/pattern/pattern.h>
#include <executorch/kernels/portable/cpu/util/functional_util.h>
#include <executorch/runtime/kernel/kernel_includes.h>

using ::executorch::aten::ScalarType;
using ::executorch::aten::Tensor;
using ::executorch::runtime::Error;
using ::executorch::runtime::KernelRuntimeContext;

namespace cadence {
namespace impl {
namespace G3 {
namespace native {

namespace {

double rsqrt(double x) {
  return 1.0 / std::sqrt(x);
}

} // namespace

Tensor& rsqrt_out(KernelRuntimeContext& ctx, const Tensor& in, Tensor& out) {
#ifdef OP_ARG_CHECK
  // Resize for dynamic shape
  ET_KERNEL_CHECK_MSG(
      ctx,
      executorch::runtime::resize_tensor(out, in.sizes()) == Error::Ok,
      InvalidArgument,
      out,
      "Failed to resize output tensor.");

  ET_KERNEL_CHECK(
      ctx,
      executorch::runtime::tensors_have_same_dim_order(in, out),
      InvalidArgument,
      out);
#endif

  if ((in.scalar_type() == ScalarType::Float) &&
      (out.scalar_type() == ScalarType::Float)) {
    float* const out_data = out.mutable_data_ptr<float>();
    const float* const in_data = in.const_data_ptr<float>();

    XT_KERNEL_CHECK(
        ctx, out, xa_nn_elm_rsqrt_f32_f32, out_data, in_data, out.numel());

    return out;
  } else {
    return torch::executor::native::internal::
        unary_ufunc_realhbbf16_to_floathbf16(rsqrt, ctx, in, out);
  }
}

} // namespace native
} // namespace G3
} // namespace impl
} // namespace cadence