/*

 * AltiVec optimizations for libjpeg-turbo

 *

 * Copyright (C) 2015, D. R. Commander.  All Rights Reserved.

 *

 * This software is provided 'as-is', without any express or implied

 * warranty.  In no event will the authors be held liable for any damages

 * arising from the use of this software.

 *

 * Permission is granted to anyone to use this software for any purpose,

 * including commercial applications, and to alter it and redistribute it

 * freely, subject to the following restrictions:

 *

 * 1. The origin of this software must not be misrepresented; you must not

 *    claim that you wrote the original software. If you use this software

 *    in a product, an acknowledgment in the product documentation would be

 *    appreciated but is not required.

 * 2. Altered source versions must be plainly marked as such, and must not be

 *    misrepresented as being the original software.

 * 3. This notice may not be removed or altered from any source distribution.

 */

/* CHROMA DOWNSAMPLING */

#include "jsimd_altivec.h"

#include "jcsample.h"

void jsimd_h2v1_downsample_altivec(JDIMENSION image_width,

                                   int max_v_samp_factor,

                                   JDIMENSION v_samp_factor,

                                   JDIMENSION width_in_blocks,

                                   JSAMPARRAY input_data,

                                   JSAMPARRAY output_data)

{

  int outrow, outcol;

  JDIMENSION output_cols = width_in_blocks * DCTSIZE;

  JSAMPROW inptr, outptr;

  __vector unsigned char this0, next0, out;

  __vector unsigned short this0e, this0o, next0e, next0o, outl, outh;

  /* Constants */

  __vector unsigned short pw_bias = { __4X2(0, 1) },

    pw_one = { __8X(1) };

  __vector unsigned char even_odd_index =

    {  0,  2,  4,  6,  8, 10, 12, 14,  1,  3,  5,  7,  9, 11, 13, 15 },

    pb_zero = { __16X(0) };

  expand_right_edge(input_data, max_v_samp_factor, image_width,

                    output_cols * 2);

  for (outrow = 0; outrow < v_samp_factor; outrow++) {

    outptr = output_data[outrow];

    inptr = input_data[outrow];

    for (outcol = output_cols; outcol > 0;

         outcol -= 16, inptr += 32, outptr += 16) {

      this0 = vec_ld(0, inptr);

      this0 = vec_perm(this0, this0, even_odd_index);

      this0e = (__vector unsigned short)VEC_UNPACKHU(this0);

      this0o = (__vector unsigned short)VEC_UNPACKLU(this0);

      outl = vec_add(this0e, this0o);

      outl = vec_add(outl, pw_bias);

      outl = vec_sr(outl, pw_one);

      if (outcol > 8) {

        next0 = vec_ld(16, inptr);

        next0 = vec_perm(next0, next0, even_odd_index);

        next0e = (__vector unsigned short)VEC_UNPACKHU(next0);

        next0o = (__vector unsigned short)VEC_UNPACKLU(next0);

        outh = vec_add(next0e, next0o);

        outh = vec_add(outh, pw_bias);

        outh = vec_sr(outh, pw_one);

      } else

        outh = vec_splat_u16(0);

      out = vec_pack(outl, outh);

      vec_st(out, 0, outptr);

    }

  }

}

void

jsimd_h2v2_downsample_altivec(JDIMENSION image_width, int max_v_samp_factor,

                              JDIMENSION v_samp_factor,

                              JDIMENSION width_in_blocks,

                              JSAMPARRAY input_data, JSAMPARRAY output_data)

{

  int inrow, outrow, outcol;

  JDIMENSION output_cols = width_in_blocks * DCTSIZE;

  JSAMPROW inptr0, inptr1, outptr;

  __vector unsigned char this0, next0, this1, next1, out;

  __vector unsigned short this0e, this0o, next0e, next0o, this1e, this1o,

    next1e, next1o, out0l, out0h, out1l, out1h, outl, outh;

  /* Constants */

  __vector unsigned short pw_bias = { __4X2(1, 2) },

    pw_two = { __8X(2) };

  __vector unsigned char even_odd_index =

    {  0,  2,  4,  6,  8, 10, 12, 14,  1,  3,  5,  7,  9, 11, 13, 15 },

    pb_zero = { __16X(0) };

  expand_right_edge(input_data, max_v_samp_factor, image_width,

                    output_cols * 2);

  for (inrow = 0, outrow = 0; outrow < v_samp_factor;

       inrow += 2, outrow++) {

    inptr0 = input_data[inrow];

    inptr1 = input_data[inrow + 1];

    outptr = output_data[outrow];

    for (outcol = output_cols; outcol > 0;

         outcol -= 16, inptr0 += 32, inptr1 += 32, outptr += 16) {

      this0 = vec_ld(0, inptr0);

      this0 = vec_perm(this0, this0, even_odd_index);

      this0e = (__vector unsigned short)VEC_UNPACKHU(this0);

      this0o = (__vector unsigned short)VEC_UNPACKLU(this0);

      out0l = vec_add(this0e, this0o);

      this1 = vec_ld(0, inptr1);

      this1 = vec_perm(this1, this1, even_odd_index);

      this1e = (__vector unsigned short)VEC_UNPACKHU(this1);

      this1o = (__vector unsigned short)VEC_UNPACKLU(this1);

      out1l = vec_add(this1e, this1o);

      outl = vec_add(out0l, out1l);

      outl = vec_add(outl, pw_bias);

      outl = vec_sr(outl, pw_two);

      if (outcol > 8) {

        next0 = vec_ld(16, inptr0);

        next0 = vec_perm(next0, next0, even_odd_index);

        next0e = (__vector unsigned short)VEC_UNPACKHU(next0);

        next0o = (__vector unsigned short)VEC_UNPACKLU(next0);

        out0h = vec_add(next0e, next0o);

        next1 = vec_ld(16, inptr1);

        next1 = vec_perm(next1, next1, even_odd_index);

        next1e = (__vector unsigned short)VEC_UNPACKHU(next1);

        next1o = (__vector unsigned short)VEC_UNPACKLU(next1);

        out1h = vec_add(next1e, next1o);

        outh = vec_add(out0h, out1h);

        outh = vec_add(outh, pw_bias);

        outh = vec_sr(outh, pw_two);

      } else

        outh = vec_splat_u16(0);

      out = vec_pack(outl, outh);

      vec_st(out, 0, outptr);

    }

  }

}