/*
 * AltiVec optimizations for libjpeg-turbo
 *
 * Copyright (C) 2014, 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.
 */

/* INTEGER QUANTIZATION AND SAMPLE CONVERSION */

#include "jsimd_altivec.h"


/* NOTE: The address will either be aligned or offset by 8 bytes, so we can
 * always get the data we want by using a single vector load (although we may
 * have to permute the result.)
 */
#define LOAD_ROW(row) {  \
  elemptr = sample_data[row] + start_col;  \
  in##row = vec_ld(0, elemptr);  \
  if ((size_t)elemptr & 15)  \
    in##row = vec_perm(in##row, in##row, vec_lvsl(0, elemptr));  \
}


void
jsimd_convsamp_altivec (JSAMPARRAY sample_data, JDIMENSION start_col,
                        DCTELEM * workspace)
{
  JSAMPROW elemptr;
  __vector unsigned char in0, in1, in2, in3, in4, in5, in6, in7;
  __vector short out0, out1, out2, out3, out4, out5, out6, out7;

  /* Constants */
  __vector short pw_centerjsamp = { __8X(CENTERJSAMPLE) };
  __vector unsigned char zero = { __16X(0) };

  LOAD_ROW(0);
  LOAD_ROW(1);
  LOAD_ROW(2);
  LOAD_ROW(3);
  LOAD_ROW(4);
  LOAD_ROW(5);
  LOAD_ROW(6);
  LOAD_ROW(7);

  out0 = (__vector short)vec_mergeh(zero, in0);
  out1 = (__vector short)vec_mergeh(zero, in1);
  out2 = (__vector short)vec_mergeh(zero, in2);
  out3 = (__vector short)vec_mergeh(zero, in3);
  out4 = (__vector short)vec_mergeh(zero, in4);
  out5 = (__vector short)vec_mergeh(zero, in5);
  out6 = (__vector short)vec_mergeh(zero, in6);
  out7 = (__vector short)vec_mergeh(zero, in7);

  out0 = vec_sub(out0, pw_centerjsamp);
  out1 = vec_sub(out1, pw_centerjsamp);
  out2 = vec_sub(out2, pw_centerjsamp);
  out3 = vec_sub(out3, pw_centerjsamp);
  out4 = vec_sub(out4, pw_centerjsamp);
  out5 = vec_sub(out5, pw_centerjsamp);
  out6 = vec_sub(out6, pw_centerjsamp);
  out7 = vec_sub(out7, pw_centerjsamp);

  vec_st(out0, 0, workspace);
  vec_st(out1, 16, workspace);
  vec_st(out2, 32, workspace);
  vec_st(out3, 48, workspace);
  vec_st(out4, 64, workspace);
  vec_st(out5, 80, workspace);
  vec_st(out6, 96, workspace);
  vec_st(out7, 112, workspace);
}


#define WORD_BIT 16

/* There is no AltiVec unsigned multiply instruction, hence this. */

#define MULTIPLY(vs0, vs1, out) {  \
  tmpe = vec_mule((__vector unsigned short)vs0,  \
                  (__vector unsigned short)vs1);  \
  tmpo = vec_mulo((__vector unsigned short)vs0,  \
                  (__vector unsigned short)vs1);  \
  out = (__vector short)vec_perm((__vector unsigned short)tmpe,  \
                                 (__vector unsigned short)tmpo,  \
                                 shift_pack_index);  \
}

void
jsimd_quantize_altivec (JCOEFPTR coef_block, DCTELEM * divisors,
                        DCTELEM * workspace)
{
  __vector short row0, row1, row2, row3, row4, row5, row6, row7;
  __vector short row0s, row1s, row2s, row3s, row4s, row5s, row6s, row7s;
  __vector short corr0, corr1, corr2, corr3, corr4, corr5, corr6, corr7;
  __vector short recip0, recip1, recip2, recip3, recip4, recip5, recip6,
    recip7;
  __vector short scale0, scale1, scale2, scale3, scale4, scale5, scale6,
    scale7;
  __vector unsigned int tmpe, tmpo;

  /* Constants */
  __vector unsigned short pw_word_bit_m1 = { __8X(WORD_BIT - 1) };
  __vector unsigned char shift_pack_index =
      { 0, 1, 16, 17, 4, 5, 20, 21, 8, 9, 24, 25, 12, 13, 28, 29};

  row0 = vec_ld(0, workspace);
  row1 = vec_ld(16, workspace);
  row2 = vec_ld(32, workspace);
  row3 = vec_ld(48, workspace);
  row4 = vec_ld(64, workspace);
  row5 = vec_ld(80, workspace);
  row6 = vec_ld(96, workspace);
  row7 = vec_ld(112, workspace);

  /* Branch-less absolute value */
  row0s = vec_sra(row0, pw_word_bit_m1);
  row1s = vec_sra(row1, pw_word_bit_m1);
  row2s = vec_sra(row2, pw_word_bit_m1);
  row3s = vec_sra(row3, pw_word_bit_m1);
  row4s = vec_sra(row4, pw_word_bit_m1);
  row5s = vec_sra(row5, pw_word_bit_m1);
  row6s = vec_sra(row6, pw_word_bit_m1);
  row7s = vec_sra(row7, pw_word_bit_m1);
  row0 = vec_xor(row0, row0s);
  row1 = vec_xor(row1, row1s);
  row2 = vec_xor(row2, row2s);
  row3 = vec_xor(row3, row3s);
  row4 = vec_xor(row4, row4s);
  row5 = vec_xor(row5, row5s);
  row6 = vec_xor(row6, row6s);
  row7 = vec_xor(row7, row7s);
  row0 = vec_sub(row0, row0s);
  row1 = vec_sub(row1, row1s);
  row2 = vec_sub(row2, row2s);
  row3 = vec_sub(row3, row3s);
  row4 = vec_sub(row4, row4s);
  row5 = vec_sub(row5, row5s);
  row6 = vec_sub(row6, row6s);
  row7 = vec_sub(row7, row7s);

  corr0 = vec_ld(DCTSIZE2 * 2, divisors);
  corr1 = vec_ld(DCTSIZE2 * 2 + 16, divisors);
  corr2 = vec_ld(DCTSIZE2 * 2 + 32, divisors);
  corr3 = vec_ld(DCTSIZE2 * 2 + 48, divisors);
  corr4 = vec_ld(DCTSIZE2 * 2 + 64, divisors);
  corr5 = vec_ld(DCTSIZE2 * 2 + 80, divisors);
  corr6 = vec_ld(DCTSIZE2 * 2 + 96, divisors);
  corr7 = vec_ld(DCTSIZE2 * 2 + 112, divisors);

  row0 = vec_add(row0, corr0);
  row1 = vec_add(row1, corr1);
  row2 = vec_add(row2, corr2);
  row3 = vec_add(row3, corr3);
  row4 = vec_add(row4, corr4);
  row5 = vec_add(row5, corr5);
  row6 = vec_add(row6, corr6);
  row7 = vec_add(row7, corr7);

  recip0 = vec_ld(0, divisors);
  recip1 = vec_ld(16, divisors);
  recip2 = vec_ld(32, divisors);
  recip3 = vec_ld(48, divisors);
  recip4 = vec_ld(64, divisors);
  recip5 = vec_ld(80, divisors);
  recip6 = vec_ld(96, divisors);
  recip7 = vec_ld(112, divisors);

  MULTIPLY(row0, recip0, row0);
  MULTIPLY(row1, recip1, row1);
  MULTIPLY(row2, recip2, row2);
  MULTIPLY(row3, recip3, row3);
  MULTIPLY(row4, recip4, row4);
  MULTIPLY(row5, recip5, row5);
  MULTIPLY(row6, recip6, row6);
  MULTIPLY(row7, recip7, row7);

  scale0 = vec_ld(DCTSIZE2 * 4, divisors);
  scale1 = vec_ld(DCTSIZE2 * 4 + 16, divisors);
  scale2 = vec_ld(DCTSIZE2 * 4 + 32, divisors);
  scale3 = vec_ld(DCTSIZE2 * 4 + 48, divisors);
  scale4 = vec_ld(DCTSIZE2 * 4 + 64, divisors);
  scale5 = vec_ld(DCTSIZE2 * 4 + 80, divisors);
  scale6 = vec_ld(DCTSIZE2 * 4 + 96, divisors);
  scale7 = vec_ld(DCTSIZE2 * 4 + 112, divisors);

  MULTIPLY(row0, scale0, row0);
  MULTIPLY(row1, scale1, row1);
  MULTIPLY(row2, scale2, row2);
  MULTIPLY(row3, scale3, row3);
  MULTIPLY(row4, scale4, row4);
  MULTIPLY(row5, scale5, row5);
  MULTIPLY(row6, scale6, row6);
  MULTIPLY(row7, scale7, row7);

  row0 = vec_xor(row0, row0s);
  row1 = vec_xor(row1, row1s);
  row2 = vec_xor(row2, row2s);
  row3 = vec_xor(row3, row3s);
  row4 = vec_xor(row4, row4s);
  row5 = vec_xor(row5, row5s);
  row6 = vec_xor(row6, row6s);
  row7 = vec_xor(row7, row7s);
  row0 = vec_sub(row0, row0s);
  row1 = vec_sub(row1, row1s);
  row2 = vec_sub(row2, row2s);
  row3 = vec_sub(row3, row3s);
  row4 = vec_sub(row4, row4s);
  row5 = vec_sub(row5, row5s);
  row6 = vec_sub(row6, row6s);
  row7 = vec_sub(row7, row7s);

  vec_st(row0, 0, coef_block);
  vec_st(row1, 16, coef_block);
  vec_st(row2, 32, coef_block);
  vec_st(row3, 48, coef_block);
  vec_st(row4, 64, coef_block);
  vec_st(row5, 80, coef_block);
  vec_st(row6, 96, coef_block);
  vec_st(row7, 112, coef_block);
}