ffmpeg / libavcodec / ppc / mpegvideo_altivec.c @ b550bfaa
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/*


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* Copyright (c) 2002 Dieter Shirley

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*

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* dct_unquantize_h263_altivec:

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* Copyright (c) 2003 Romain Dolbeau <romain@dolbeau.org>

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*

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* This file is part of FFmpeg.

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*

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* FFmpeg is free software; you can redistribute it and/or

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* modify it under the terms of the GNU Lesser General Public

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* License as published by the Free Software Foundation; either

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* version 2.1 of the License, or (at your option) any later version.

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*

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* FFmpeg is distributed in the hope that it will be useful,

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* but WITHOUT ANY WARRANTY; without even the implied warranty of

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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

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* Lesser General Public License for more details.

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*

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* You should have received a copy of the GNU Lesser General Public

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* License along with FFmpeg; if not, write to the Free Software

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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 021101301 USA

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*/

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#include <stdlib.h> 
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#include <stdio.h> 
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#include "dsputil.h" 
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#include "mpegvideo.h" 
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#include "gcc_fixes.h" 
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#include "dsputil_altivec.h" 
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// Swaps two variables (used for altivec registers)

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#define SWAP(a,b) \

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do { \

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__typeof__(a) swap_temp=a; \ 
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a=b; \ 
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b=swap_temp; \ 
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} while (0) 
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// transposes a matrix consisting of four vectors with four elements each

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#define TRANSPOSE4(a,b,c,d) \

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do { \

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__typeof__(a) _trans_ach = vec_mergeh(a, c); \ 
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__typeof__(a) _trans_acl = vec_mergel(a, c); \ 
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__typeof__(a) _trans_bdh = vec_mergeh(b, d); \ 
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__typeof__(a) _trans_bdl = vec_mergel(b, d); \ 
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\ 
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a = vec_mergeh(_trans_ach, _trans_bdh); \ 
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b = vec_mergel(_trans_ach, _trans_bdh); \ 
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c = vec_mergeh(_trans_acl, _trans_bdl); \ 
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d = vec_mergel(_trans_acl, _trans_bdl); \ 
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} while (0) 
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// Loads a fourbyte value (int or float) from the target address

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// into every element in the target vector. Only works if the

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// target address is fourbyte aligned (which should be always).

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#define LOAD4(vec, address) \

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{ \ 
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__typeof__(vec)* _load_addr = (__typeof__(vec)*)(address); \ 
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vector unsigned char _perm_vec = vec_lvsl(0,(address)); \ 
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vec = vec_ld(0, _load_addr); \

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vec = vec_perm(vec, vec, _perm_vec); \ 
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vec = vec_splat(vec, 0); \

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} 
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#ifdef CONFIG_DARWIN

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#define FOUROF(a) (a)

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#else

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// slower, for dumb nonapple GCC

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#define FOUROF(a) {a,a,a,a}

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#endif

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int dct_quantize_altivec(MpegEncContext* s,

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DCTELEM* data, int n,

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int qscale, int* overflow) 
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{ 
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int lastNonZero;

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vector float row0, row1, row2, row3, row4, row5, row6, row7;

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vector float alt0, alt1, alt2, alt3, alt4, alt5, alt6, alt7;

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const_vector float zero = (const_vector float)FOUROF(0.); 
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// used after quantise step

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int oldBaseValue = 0; 
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// Load the data into the row/alt vectors

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{ 
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vector signed short data0, data1, data2, data3, data4, data5, data6, data7; 
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data0 = vec_ld(0, data);

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data1 = vec_ld(16, data);

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data2 = vec_ld(32, data);

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data3 = vec_ld(48, data);

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data4 = vec_ld(64, data);

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data5 = vec_ld(80, data);

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data6 = vec_ld(96, data);

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data7 = vec_ld(112, data);

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// Transpose the data before we start

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TRANSPOSE8(data0, data1, data2, data3, data4, data5, data6, data7); 
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// load the data into floating point vectors. We load

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// the high half of each row into the main row vectors

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// and the low half into the alt vectors.

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row0 = vec_ctf(vec_unpackh(data0), 0);

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alt0 = vec_ctf(vec_unpackl(data0), 0);

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row1 = vec_ctf(vec_unpackh(data1), 0);

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alt1 = vec_ctf(vec_unpackl(data1), 0);

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row2 = vec_ctf(vec_unpackh(data2), 0);

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alt2 = vec_ctf(vec_unpackl(data2), 0);

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row3 = vec_ctf(vec_unpackh(data3), 0);

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alt3 = vec_ctf(vec_unpackl(data3), 0);

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row4 = vec_ctf(vec_unpackh(data4), 0);

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alt4 = vec_ctf(vec_unpackl(data4), 0);

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row5 = vec_ctf(vec_unpackh(data5), 0);

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alt5 = vec_ctf(vec_unpackl(data5), 0);

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row6 = vec_ctf(vec_unpackh(data6), 0);

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alt6 = vec_ctf(vec_unpackl(data6), 0);

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row7 = vec_ctf(vec_unpackh(data7), 0);

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alt7 = vec_ctf(vec_unpackl(data7), 0);

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} 
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// The following block could exist as a separate an altivec dct

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// function. However, if we put it inline, the DCT data can remain

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// in the vector local variables, as floats, which we'll use during the

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// quantize step...

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{ 
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const vector float vec_0_298631336 = (vector float)FOUROF(0.298631336f); 
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const vector float vec_0_390180644 = (vector float)FOUROF(0.390180644f); 
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const vector float vec_0_541196100 = (vector float)FOUROF(0.541196100f); 
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const vector float vec_0_765366865 = (vector float)FOUROF(0.765366865f); 
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const vector float vec_0_899976223 = (vector float)FOUROF(0.899976223f); 
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const vector float vec_1_175875602 = (vector float)FOUROF(1.175875602f); 
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const vector float vec_1_501321110 = (vector float)FOUROF(1.501321110f); 
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const vector float vec_1_847759065 = (vector float)FOUROF(1.847759065f); 
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const vector float vec_1_961570560 = (vector float)FOUROF(1.961570560f); 
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const vector float vec_2_053119869 = (vector float)FOUROF(2.053119869f); 
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const vector float vec_2_562915447 = (vector float)FOUROF(2.562915447f); 
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const vector float vec_3_072711026 = (vector float)FOUROF(3.072711026f); 
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int whichPass, whichHalf;

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for(whichPass = 1; whichPass<=2; whichPass++) 
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{ 
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for(whichHalf = 1; whichHalf<=2; whichHalf++) 
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{ 
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vector float tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;

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vector float tmp10, tmp11, tmp12, tmp13;

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vector float z1, z2, z3, z4, z5;

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tmp0 = vec_add(row0, row7); // tmp0 = dataptr[0] + dataptr[7];

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tmp7 = vec_sub(row0, row7); // tmp7 = dataptr[0]  dataptr[7];

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tmp3 = vec_add(row3, row4); // tmp3 = dataptr[3] + dataptr[4];

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tmp4 = vec_sub(row3, row4); // tmp4 = dataptr[3]  dataptr[4];

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tmp1 = vec_add(row1, row6); // tmp1 = dataptr[1] + dataptr[6];

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tmp6 = vec_sub(row1, row6); // tmp6 = dataptr[1]  dataptr[6];

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tmp2 = vec_add(row2, row5); // tmp2 = dataptr[2] + dataptr[5];

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tmp5 = vec_sub(row2, row5); // tmp5 = dataptr[2]  dataptr[5];

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tmp10 = vec_add(tmp0, tmp3); // tmp10 = tmp0 + tmp3;

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tmp13 = vec_sub(tmp0, tmp3); // tmp13 = tmp0  tmp3;

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tmp11 = vec_add(tmp1, tmp2); // tmp11 = tmp1 + tmp2;

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tmp12 = vec_sub(tmp1, tmp2); // tmp12 = tmp1  tmp2;

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// dataptr[0] = (DCTELEM) ((tmp10 + tmp11) << PASS1_BITS);

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row0 = vec_add(tmp10, tmp11); 
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// dataptr[4] = (DCTELEM) ((tmp10  tmp11) << PASS1_BITS);

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row4 = vec_sub(tmp10, tmp11); 
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// z1 = MULTIPLY(tmp12 + tmp13, FIX_0_541196100);

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z1 = vec_madd(vec_add(tmp12, tmp13), vec_0_541196100, (vector float)zero);

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// dataptr[2] = (DCTELEM) DESCALE(z1 + MULTIPLY(tmp13, FIX_0_765366865),

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// CONST_BITSPASS1_BITS);

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row2 = vec_madd(tmp13, vec_0_765366865, z1); 
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// dataptr[6] = (DCTELEM) DESCALE(z1 + MULTIPLY(tmp12,  FIX_1_847759065),

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// CONST_BITSPASS1_BITS);

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row6 = vec_madd(tmp12, vec_1_847759065, z1); 
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z1 = vec_add(tmp4, tmp7); // z1 = tmp4 + tmp7;

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z2 = vec_add(tmp5, tmp6); // z2 = tmp5 + tmp6;

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z3 = vec_add(tmp4, tmp6); // z3 = tmp4 + tmp6;

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z4 = vec_add(tmp5, tmp7); // z4 = tmp5 + tmp7;

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// z5 = MULTIPLY(z3 + z4, FIX_1_175875602); /* sqrt(2) * c3 */

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z5 = vec_madd(vec_add(z3, z4), vec_1_175875602, (vector float)zero);

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// z3 = MULTIPLY(z3,  FIX_1_961570560); /* sqrt(2) * (c3c5) */

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z3 = vec_madd(z3, vec_1_961570560, z5); 
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// z4 = MULTIPLY(z4,  FIX_0_390180644); /* sqrt(2) * (c5c3) */

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z4 = vec_madd(z4, vec_0_390180644, z5); 
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// The following adds are rolled into the multiplies above

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// z3 = vec_add(z3, z5); // z3 += z5;

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// z4 = vec_add(z4, z5); // z4 += z5;

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// z2 = MULTIPLY(z2,  FIX_2_562915447); /* sqrt(2) * (c1c3) */

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// Wow! It's actually more effecient to roll this multiply

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// into the adds below, even thought the multiply gets done twice!

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// z2 = vec_madd(z2, vec_2_562915447, (vector float)zero);

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// z1 = MULTIPLY(z1,  FIX_0_899976223); /* sqrt(2) * (c7c3) */

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// Same with this one...

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// z1 = vec_madd(z1, vec_0_899976223, (vector float)zero);

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// tmp4 = MULTIPLY(tmp4, FIX_0_298631336); /* sqrt(2) * (c1+c3+c5c7) */

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// dataptr[7] = (DCTELEM) DESCALE(tmp4 + z1 + z3, CONST_BITSPASS1_BITS);

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row7 = vec_madd(tmp4, vec_0_298631336, vec_madd(z1, vec_0_899976223, z3)); 
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// tmp5 = MULTIPLY(tmp5, FIX_2_053119869); /* sqrt(2) * ( c1+c3c5+c7) */

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// dataptr[5] = (DCTELEM) DESCALE(tmp5 + z2 + z4, CONST_BITSPASS1_BITS);

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row5 = vec_madd(tmp5, vec_2_053119869, vec_madd(z2, vec_2_562915447, z4)); 
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// tmp6 = MULTIPLY(tmp6, FIX_3_072711026); /* sqrt(2) * ( c1+c3+c5c7) */

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// dataptr[3] = (DCTELEM) DESCALE(tmp6 + z2 + z3, CONST_BITSPASS1_BITS);

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row3 = vec_madd(tmp6, vec_3_072711026, vec_madd(z2, vec_2_562915447, z3)); 
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// tmp7 = MULTIPLY(tmp7, FIX_1_501321110); /* sqrt(2) * ( c1+c3c5c7) */

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// dataptr[1] = (DCTELEM) DESCALE(tmp7 + z1 + z4, CONST_BITSPASS1_BITS);

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row1 = vec_madd(z1, vec_0_899976223, vec_madd(tmp7, vec_1_501321110, z4)); 
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// Swap the row values with the alts. If this is the first half,

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// this sets up the low values to be acted on in the second half.

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// If this is the second half, it puts the high values back in

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// the row values where they are expected to be when we're done.

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SWAP(row0, alt0); 
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SWAP(row1, alt1); 
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SWAP(row2, alt2); 
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SWAP(row3, alt3); 
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SWAP(row4, alt4); 
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SWAP(row5, alt5); 
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SWAP(row6, alt6); 
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SWAP(row7, alt7); 
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} 
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if (whichPass == 1) 
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{ 
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// transpose the data for the second pass

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// First, block transpose the upper right with lower left.

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SWAP(row4, alt0); 
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SWAP(row5, alt1); 
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SWAP(row6, alt2); 
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SWAP(row7, alt3); 
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// Now, transpose each block of four

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TRANSPOSE4(row0, row1, row2, row3); 
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TRANSPOSE4(row4, row5, row6, row7); 
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TRANSPOSE4(alt0, alt1, alt2, alt3); 
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TRANSPOSE4(alt4, alt5, alt6, alt7); 
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} 
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} 
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} 
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// perform the quantise step, using the floating point data

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// still in the row/alt registers

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{ 
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const int* biasAddr; 
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const vector signed int* qmat; 
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vector float bias, negBias;

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if (s>mb_intra)

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{ 
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vector signed int baseVector; 
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// We must cache element 0 in the intra case

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// (it needs special handling).

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baseVector = vec_cts(vec_splat(row0, 0), 0); 
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vec_ste(baseVector, 0, &oldBaseValue);

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qmat = (vector signed int*)s>q_intra_matrix[qscale]; 
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biasAddr = &(s>intra_quant_bias); 
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} 
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else

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{ 
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qmat = (vector signed int*)s>q_inter_matrix[qscale]; 
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biasAddr = &(s>inter_quant_bias); 
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} 
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// Load the bias vector (We add 0.5 to the bias so that we're

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// rounding when we convert to int, instead of flooring.)

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{ 
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vector signed int biasInt; 
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const vector float negOneFloat = (vector float)FOUROF(1.0f); 
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LOAD4(biasInt, biasAddr); 
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bias = vec_ctf(biasInt, QUANT_BIAS_SHIFT); 
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negBias = vec_madd(bias, negOneFloat, zero); 
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} 
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{ 
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vector float q0, q1, q2, q3, q4, q5, q6, q7;

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q0 = vec_ctf(qmat[0], QMAT_SHIFT);

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q1 = vec_ctf(qmat[2], QMAT_SHIFT);

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q2 = vec_ctf(qmat[4], QMAT_SHIFT);

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q3 = vec_ctf(qmat[6], QMAT_SHIFT);

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q4 = vec_ctf(qmat[8], QMAT_SHIFT);

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q5 = vec_ctf(qmat[10], QMAT_SHIFT);

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q6 = vec_ctf(qmat[12], QMAT_SHIFT);

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q7 = vec_ctf(qmat[14], QMAT_SHIFT);

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row0 = vec_sel(vec_madd(row0, q0, negBias), vec_madd(row0, q0, bias), 
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vec_cmpgt(row0, zero)); 
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row1 = vec_sel(vec_madd(row1, q1, negBias), vec_madd(row1, q1, bias), 
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vec_cmpgt(row1, zero)); 
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row2 = vec_sel(vec_madd(row2, q2, negBias), vec_madd(row2, q2, bias), 
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vec_cmpgt(row2, zero)); 
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row3 = vec_sel(vec_madd(row3, q3, negBias), vec_madd(row3, q3, bias), 
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vec_cmpgt(row3, zero)); 
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row4 = vec_sel(vec_madd(row4, q4, negBias), vec_madd(row4, q4, bias), 
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vec_cmpgt(row4, zero)); 
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row5 = vec_sel(vec_madd(row5, q5, negBias), vec_madd(row5, q5, bias), 
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vec_cmpgt(row5, zero)); 
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row6 = vec_sel(vec_madd(row6, q6, negBias), vec_madd(row6, q6, bias), 
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vec_cmpgt(row6, zero)); 
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row7 = vec_sel(vec_madd(row7, q7, negBias), vec_madd(row7, q7, bias), 
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vec_cmpgt(row7, zero)); 
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q0 = vec_ctf(qmat[1], QMAT_SHIFT);

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q1 = vec_ctf(qmat[3], QMAT_SHIFT);

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q2 = vec_ctf(qmat[5], QMAT_SHIFT);

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q3 = vec_ctf(qmat[7], QMAT_SHIFT);

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q4 = vec_ctf(qmat[9], QMAT_SHIFT);

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q5 = vec_ctf(qmat[11], QMAT_SHIFT);

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q6 = vec_ctf(qmat[13], QMAT_SHIFT);

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q7 = vec_ctf(qmat[15], QMAT_SHIFT);

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alt0 = vec_sel(vec_madd(alt0, q0, negBias), vec_madd(alt0, q0, bias), 
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vec_cmpgt(alt0, zero)); 
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alt1 = vec_sel(vec_madd(alt1, q1, negBias), vec_madd(alt1, q1, bias), 
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vec_cmpgt(alt1, zero)); 
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alt2 = vec_sel(vec_madd(alt2, q2, negBias), vec_madd(alt2, q2, bias), 
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vec_cmpgt(alt2, zero)); 
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alt3 = vec_sel(vec_madd(alt3, q3, negBias), vec_madd(alt3, q3, bias), 
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vec_cmpgt(alt3, zero)); 
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alt4 = vec_sel(vec_madd(alt4, q4, negBias), vec_madd(alt4, q4, bias), 
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vec_cmpgt(alt4, zero)); 
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alt5 = vec_sel(vec_madd(alt5, q5, negBias), vec_madd(alt5, q5, bias), 
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vec_cmpgt(alt5, zero)); 
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alt6 = vec_sel(vec_madd(alt6, q6, negBias), vec_madd(alt6, q6, bias), 
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vec_cmpgt(alt6, zero)); 
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alt7 = vec_sel(vec_madd(alt7, q7, negBias), vec_madd(alt7, q7, bias), 
349 
vec_cmpgt(alt7, zero)); 
350 
} 
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} 
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// Store the data back into the original block

356 
{ 
357 
vector signed short data0, data1, data2, data3, data4, data5, data6, data7; 
358  
359 
data0 = vec_pack(vec_cts(row0, 0), vec_cts(alt0, 0)); 
360 
data1 = vec_pack(vec_cts(row1, 0), vec_cts(alt1, 0)); 
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data2 = vec_pack(vec_cts(row2, 0), vec_cts(alt2, 0)); 
362 
data3 = vec_pack(vec_cts(row3, 0), vec_cts(alt3, 0)); 
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data4 = vec_pack(vec_cts(row4, 0), vec_cts(alt4, 0)); 
364 
data5 = vec_pack(vec_cts(row5, 0), vec_cts(alt5, 0)); 
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data6 = vec_pack(vec_cts(row6, 0), vec_cts(alt6, 0)); 
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data7 = vec_pack(vec_cts(row7, 0), vec_cts(alt7, 0)); 
367  
368 
{ 
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// Clamp for overflow

370 
vector signed int max_q_int, min_q_int; 
371 
vector signed short max_q, min_q; 
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LOAD4(max_q_int, &(s>max_qcoeff)); 
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LOAD4(min_q_int, &(s>min_qcoeff)); 
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max_q = vec_pack(max_q_int, max_q_int); 
377 
min_q = vec_pack(min_q_int, min_q_int); 
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data0 = vec_max(vec_min(data0, max_q), min_q); 
380 
data1 = vec_max(vec_min(data1, max_q), min_q); 
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data2 = vec_max(vec_min(data2, max_q), min_q); 
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data4 = vec_max(vec_min(data4, max_q), min_q); 
383 
data5 = vec_max(vec_min(data5, max_q), min_q); 
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data6 = vec_max(vec_min(data6, max_q), min_q); 
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data7 = vec_max(vec_min(data7, max_q), min_q); 
386 
} 
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{ 
389 
vector bool char zero_01, zero_23, zero_45, zero_67; 
390 
vector signed char scanIndices_01, scanIndices_23, scanIndices_45, scanIndices_67; 
391 
vector signed char negOne = vec_splat_s8(1); 
392 
vector signed char* scanPtr = 
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(vector signed char*)(s>intra_scantable.inverse); 
394 
signed char lastNonZeroChar; 
395  
396 
// Determine the largest nonzero index.

397 
zero_01 = vec_pack(vec_cmpeq(data0, (vector signed short)zero), 
398 
vec_cmpeq(data1, (vector signed short)zero)); 
399 
zero_23 = vec_pack(vec_cmpeq(data2, (vector signed short)zero), 
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vec_cmpeq(data3, (vector signed short)zero)); 
401 
zero_45 = vec_pack(vec_cmpeq(data4, (vector signed short)zero), 
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vec_cmpeq(data5, (vector signed short)zero)); 
403 
zero_67 = vec_pack(vec_cmpeq(data6, (vector signed short)zero), 
404 
vec_cmpeq(data7, (vector signed short)zero)); 
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406 
// 64 biggest values

407 
scanIndices_01 = vec_sel(scanPtr[0], negOne, zero_01);

408 
scanIndices_23 = vec_sel(scanPtr[1], negOne, zero_23);

409 
scanIndices_45 = vec_sel(scanPtr[2], negOne, zero_45);

410 
scanIndices_67 = vec_sel(scanPtr[3], negOne, zero_67);

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// 32 largest values

413 
scanIndices_01 = vec_max(scanIndices_01, scanIndices_23); 
414 
scanIndices_45 = vec_max(scanIndices_45, scanIndices_67); 
415  
416 
// 16 largest values

417 
scanIndices_01 = vec_max(scanIndices_01, scanIndices_45); 
418  
419 
// 8 largest values

420 
scanIndices_01 = vec_max(vec_mergeh(scanIndices_01, negOne), 
421 
vec_mergel(scanIndices_01, negOne)); 
422  
423 
// 4 largest values

424 
scanIndices_01 = vec_max(vec_mergeh(scanIndices_01, negOne), 
425 
vec_mergel(scanIndices_01, negOne)); 
426  
427 
// 2 largest values

428 
scanIndices_01 = vec_max(vec_mergeh(scanIndices_01, negOne), 
429 
vec_mergel(scanIndices_01, negOne)); 
430  
431 
// largest value

432 
scanIndices_01 = vec_max(vec_mergeh(scanIndices_01, negOne), 
433 
vec_mergel(scanIndices_01, negOne)); 
434  
435 
scanIndices_01 = vec_splat(scanIndices_01, 0);

436  
437  
438 
vec_ste(scanIndices_01, 0, &lastNonZeroChar);

439  
440 
lastNonZero = lastNonZeroChar; 
441  
442 
// While the data is still in vectors we check for the transpose IDCT permute

443 
// and handle it using the vector unit if we can. This is the permute used

444 
// by the altivec idct, so it is common when using the altivec dct.

445  
446 
if ((lastNonZero > 0) && (s>dsp.idct_permutation_type == FF_TRANSPOSE_IDCT_PERM)) 
447 
{ 
448 
TRANSPOSE8(data0, data1, data2, data3, data4, data5, data6, data7); 
449 
} 
450  
451 
vec_st(data0, 0, data);

452 
vec_st(data1, 16, data);

453 
vec_st(data2, 32, data);

454 
vec_st(data3, 48, data);

455 
vec_st(data4, 64, data);

456 
vec_st(data5, 80, data);

457 
vec_st(data6, 96, data);

458 
vec_st(data7, 112, data);

459 
} 
460 
} 
461  
462 
// special handling of block[0]

463 
if (s>mb_intra)

464 
{ 
465 
if (!s>h263_aic)

466 
{ 
467 
if (n < 4) 
468 
oldBaseValue /= s>y_dc_scale; 
469 
else

470 
oldBaseValue /= s>c_dc_scale; 
471 
} 
472  
473 
// Divide by 8, rounding the result

474 
data[0] = (oldBaseValue + 4) >> 3; 
475 
} 
476  
477 
// We handled the tranpose permutation above and we don't

478 
// need to permute the "no" permutation case.

479 
if ((lastNonZero > 0) && 
480 
(s>dsp.idct_permutation_type != FF_TRANSPOSE_IDCT_PERM) && 
481 
(s>dsp.idct_permutation_type != FF_NO_IDCT_PERM)) 
482 
{ 
483 
ff_block_permute(data, s>dsp.idct_permutation, 
484 
s>intra_scantable.scantable, lastNonZero); 
485 
} 
486  
487 
return lastNonZero;

488 
} 
489 
#undef FOUROF

490  
491 
/*

492 
AltiVec version of dct_unquantize_h263

493 
this code assumes `block' is 16 bytesaligned

494 
*/

495 
void dct_unquantize_h263_altivec(MpegEncContext *s,

496 
DCTELEM *block, int n, int qscale) 
497 
{ 
498 
POWERPC_PERF_DECLARE(altivec_dct_unquantize_h263_num, 1);

499 
int i, level, qmul, qadd;

500 
int nCoeffs;

501  
502 
assert(s>block_last_index[n]>=0);

503  
504 
POWERPC_PERF_START_COUNT(altivec_dct_unquantize_h263_num, 1);

505  
506 
qadd = (qscale  1)  1; 
507 
qmul = qscale << 1;

508  
509 
if (s>mb_intra) {

510 
if (!s>h263_aic) {

511 
if (n < 4) 
512 
block[0] = block[0] * s>y_dc_scale; 
513 
else

514 
block[0] = block[0] * s>c_dc_scale; 
515 
}else

516 
qadd = 0;

517 
i = 1;

518 
nCoeffs= 63; //does not always use zigzag table 
519 
} else {

520 
i = 0;

521 
nCoeffs= s>intra_scantable.raster_end[ s>block_last_index[n] ]; 
522 
} 
523  
524 
{ 
525 
register const_vector signed short vczero = (const_vector signed short)vec_splat_s16(0); 
526 
short __attribute__ ((aligned(16))) qmul8[] = 
527 
{ 
528 
qmul, qmul, qmul, qmul, 
529 
qmul, qmul, qmul, qmul 
530 
}; 
531 
short __attribute__ ((aligned(16))) qadd8[] = 
532 
{ 
533 
qadd, qadd, qadd, qadd, 
534 
qadd, qadd, qadd, qadd 
535 
}; 
536 
short __attribute__ ((aligned(16))) nqadd8[] = 
537 
{ 
538 
qadd, qadd, qadd, qadd, 
539 
qadd, qadd, qadd, qadd 
540 
}; 
541 
register vector signed short blockv, qmulv, qaddv, nqaddv, temp1; 
542 
register vector bool short blockv_null, blockv_neg; 
543 
register short backup_0 = block[0]; 
544 
register int j = 0; 
545  
546 
qmulv = vec_ld(0, qmul8);

547 
qaddv = vec_ld(0, qadd8);

548 
nqaddv = vec_ld(0, nqadd8);

549  
550 
#if 0 // block *is* 16 bytesaligned, it seems.

551 
// first make sure block[j] is 16 bytesaligned

552 
for(j = 0; (j <= nCoeffs) && ((((unsigned long)block) + (j << 1)) & 0x0000000F) ; j++) {

553 
level = block[j];

554 
if (level) {

555 
if (level < 0) {

556 
level = level * qmul  qadd;

557 
} else {

558 
level = level * qmul + qadd;

559 
}

560 
block[j] = level;

561 
}

562 
}

563 
#endif

564  
565 
// vectorize all the 16 bytesaligned blocks

566 
// of 8 elements

567 
for(; (j + 7) <= nCoeffs ; j+=8) 
568 
{ 
569 
blockv = vec_ld(j << 1, block);

570 
blockv_neg = vec_cmplt(blockv, vczero); 
571 
blockv_null = vec_cmpeq(blockv, vczero); 
572 
// choose between +qadd or qadd as the third operand

573 
temp1 = vec_sel(qaddv, nqaddv, blockv_neg); 
574 
// multiply & add (block{i,i+7} * qmul [+] qadd)

575 
temp1 = vec_mladd(blockv, qmulv, temp1); 
576 
// put 0 where block[{i,i+7} used to have 0

577 
blockv = vec_sel(temp1, blockv, blockv_null); 
578 
vec_st(blockv, j << 1, block);

579 
} 
580  
581 
// if nCoeffs isn't a multiple of 8, finish the job

582 
// using good old scalar units.

583 
// (we could do it using a truncated vector,

584 
// but I'm not sure it's worth the hassle)

585 
for(; j <= nCoeffs ; j++) {

586 
level = block[j]; 
587 
if (level) {

588 
if (level < 0) { 
589 
level = level * qmul  qadd; 
590 
} else {

591 
level = level * qmul + qadd; 
592 
} 
593 
block[j] = level; 
594 
} 
595 
} 
596  
597 
if (i == 1) 
598 
{ // cheat. this avoid specialcasing the first iteration

599 
block[0] = backup_0;

600 
} 
601 
} 
602 
POWERPC_PERF_STOP_COUNT(altivec_dct_unquantize_h263_num, nCoeffs == 63);

603 
} 