risp4ml/isp_stages/blc_rvv.c

/*
 * Copyright 2023 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <riscv_vector.h>

#include "risp4ml/common/utils.h"
#include "risp4ml/isp_stages/blc.h"

static BlcParams blc_params = {.enable = true,
                               .offsets = {2048, 2048, 2048, 2048}};

void set_blc_params(BlcParams* params) { blc_params = *params; }

void blc_process(Image* img) {
  if (!blc_params.enable) return;

  size_t vl;
  size_t n = img->height * img->width * img->num_channels;
  uint16_t offset = blc_params.offsets[0];
  vuint16m8_t vx;  // auxiliary variable
  uint16_t* x;
  for (size_t i = 0; i < n; i += vl) {
    x = img->data + i;
    vl = __riscv_vsetvl_e16m8(n - i);
    vx = __riscv_vle16_v_u16m8(x, vl);    // load
    vx = __riscv_vssubu(vx, offset, vl);  // subtract
    __riscv_vse16(x, vx, vl);             // save
  }
}