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libavcodec/ppc/mpegvideo_altivec.c

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00001 /*
00002  * Copyright (c) 2002 Dieter Shirley
00003  *
00004  * dct_unquantize_h263_altivec:
00005  * Copyright (c) 2003 Romain Dolbeau <romain@dolbeau.org>
00006  *
00007  * This file is part of FFmpeg.
00008  *
00009  * FFmpeg is free software; you can redistribute it and/or
00010  * modify it under the terms of the GNU Lesser General Public
00011  * License as published by the Free Software Foundation; either
00012  * version 2.1 of the License, or (at your option) any later version.
00013  *
00014  * FFmpeg is distributed in the hope that it will be useful,
00015  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00016  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00017  * Lesser General Public License for more details.
00018  *
00019  * You should have received a copy of the GNU Lesser General Public
00020  * License along with FFmpeg; if not, write to the Free Software
00021  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00022  */
00023 
00024 #include <stdlib.h>
00025 #include <stdio.h>
00026 #include "libavutil/cpu.h"
00027 #include "libavcodec/dsputil.h"
00028 #include "libavcodec/mpegvideo.h"
00029 
00030 #include "util_altivec.h"
00031 #include "types_altivec.h"
00032 #include "dsputil_altivec.h"
00033 
00034 // Swaps two variables (used for altivec registers)
00035 #define SWAP(a,b) \
00036 do { \
00037     __typeof__(a) swap_temp=a; \
00038     a=b; \
00039     b=swap_temp; \
00040 } while (0)
00041 
00042 // transposes a matrix consisting of four vectors with four elements each
00043 #define TRANSPOSE4(a,b,c,d) \
00044 do { \
00045     __typeof__(a) _trans_ach = vec_mergeh(a, c); \
00046     __typeof__(a) _trans_acl = vec_mergel(a, c); \
00047     __typeof__(a) _trans_bdh = vec_mergeh(b, d); \
00048     __typeof__(a) _trans_bdl = vec_mergel(b, d); \
00049                                                  \
00050     a = vec_mergeh(_trans_ach, _trans_bdh);      \
00051     b = vec_mergel(_trans_ach, _trans_bdh);      \
00052     c = vec_mergeh(_trans_acl, _trans_bdl);      \
00053     d = vec_mergel(_trans_acl, _trans_bdl);      \
00054 } while (0)
00055 
00056 
00057 // Loads a four-byte value (int or float) from the target address
00058 // into every element in the target vector.  Only works if the
00059 // target address is four-byte aligned (which should be always).
00060 #define LOAD4(vec, address) \
00061 { \
00062     __typeof__(vec)* _load_addr = (__typeof__(vec)*)(address);  \
00063     vector unsigned char _perm_vec = vec_lvsl(0,(address));     \
00064     vec = vec_ld(0, _load_addr);                                \
00065     vec = vec_perm(vec, vec, _perm_vec);                        \
00066     vec = vec_splat(vec, 0);                                    \
00067 }
00068 
00069 
00070 #define FOUROF(a) {a,a,a,a}
00071 
00072 static int dct_quantize_altivec(MpegEncContext* s,
00073                          DCTELEM* data, int n,
00074                          int qscale, int* overflow)
00075 {
00076     int lastNonZero;
00077     vector float row0, row1, row2, row3, row4, row5, row6, row7;
00078     vector float alt0, alt1, alt2, alt3, alt4, alt5, alt6, alt7;
00079     const vector float zero = (const vector float)FOUROF(0.);
00080     // used after quantize step
00081     int oldBaseValue = 0;
00082 
00083     // Load the data into the row/alt vectors
00084     {
00085         vector signed short data0, data1, data2, data3, data4, data5, data6, data7;
00086 
00087         data0 = vec_ld(0, data);
00088         data1 = vec_ld(16, data);
00089         data2 = vec_ld(32, data);
00090         data3 = vec_ld(48, data);
00091         data4 = vec_ld(64, data);
00092         data5 = vec_ld(80, data);
00093         data6 = vec_ld(96, data);
00094         data7 = vec_ld(112, data);
00095 
00096         // Transpose the data before we start
00097         TRANSPOSE8(data0, data1, data2, data3, data4, data5, data6, data7);
00098 
00099         // load the data into floating point vectors.  We load
00100         // the high half of each row into the main row vectors
00101         // and the low half into the alt vectors.
00102         row0 = vec_ctf(vec_unpackh(data0), 0);
00103         alt0 = vec_ctf(vec_unpackl(data0), 0);
00104         row1 = vec_ctf(vec_unpackh(data1), 0);
00105         alt1 = vec_ctf(vec_unpackl(data1), 0);
00106         row2 = vec_ctf(vec_unpackh(data2), 0);
00107         alt2 = vec_ctf(vec_unpackl(data2), 0);
00108         row3 = vec_ctf(vec_unpackh(data3), 0);
00109         alt3 = vec_ctf(vec_unpackl(data3), 0);
00110         row4 = vec_ctf(vec_unpackh(data4), 0);
00111         alt4 = vec_ctf(vec_unpackl(data4), 0);
00112         row5 = vec_ctf(vec_unpackh(data5), 0);
00113         alt5 = vec_ctf(vec_unpackl(data5), 0);
00114         row6 = vec_ctf(vec_unpackh(data6), 0);
00115         alt6 = vec_ctf(vec_unpackl(data6), 0);
00116         row7 = vec_ctf(vec_unpackh(data7), 0);
00117         alt7 = vec_ctf(vec_unpackl(data7), 0);
00118     }
00119 
00120     // The following block could exist as a separate an altivec dct
00121                 // function.  However, if we put it inline, the DCT data can remain
00122                 // in the vector local variables, as floats, which we'll use during the
00123                 // quantize step...
00124     {
00125         const vector float vec_0_298631336 = (vector float)FOUROF(0.298631336f);
00126         const vector float vec_0_390180644 = (vector float)FOUROF(-0.390180644f);
00127         const vector float vec_0_541196100 = (vector float)FOUROF(0.541196100f);
00128         const vector float vec_0_765366865 = (vector float)FOUROF(0.765366865f);
00129         const vector float vec_0_899976223 = (vector float)FOUROF(-0.899976223f);
00130         const vector float vec_1_175875602 = (vector float)FOUROF(1.175875602f);
00131         const vector float vec_1_501321110 = (vector float)FOUROF(1.501321110f);
00132         const vector float vec_1_847759065 = (vector float)FOUROF(-1.847759065f);
00133         const vector float vec_1_961570560 = (vector float)FOUROF(-1.961570560f);
00134         const vector float vec_2_053119869 = (vector float)FOUROF(2.053119869f);
00135         const vector float vec_2_562915447 = (vector float)FOUROF(-2.562915447f);
00136         const vector float vec_3_072711026 = (vector float)FOUROF(3.072711026f);
00137 
00138 
00139         int whichPass, whichHalf;
00140 
00141         for(whichPass = 1; whichPass<=2; whichPass++) {
00142             for(whichHalf = 1; whichHalf<=2; whichHalf++) {
00143                 vector float tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
00144                 vector float tmp10, tmp11, tmp12, tmp13;
00145                 vector float z1, z2, z3, z4, z5;
00146 
00147                 tmp0 = vec_add(row0, row7); // tmp0 = dataptr[0] + dataptr[7];
00148                 tmp7 = vec_sub(row0, row7); // tmp7 = dataptr[0] - dataptr[7];
00149                 tmp3 = vec_add(row3, row4); // tmp3 = dataptr[3] + dataptr[4];
00150                 tmp4 = vec_sub(row3, row4); // tmp4 = dataptr[3] - dataptr[4];
00151                 tmp1 = vec_add(row1, row6); // tmp1 = dataptr[1] + dataptr[6];
00152                 tmp6 = vec_sub(row1, row6); // tmp6 = dataptr[1] - dataptr[6];
00153                 tmp2 = vec_add(row2, row5); // tmp2 = dataptr[2] + dataptr[5];
00154                 tmp5 = vec_sub(row2, row5); // tmp5 = dataptr[2] - dataptr[5];
00155 
00156                 tmp10 = vec_add(tmp0, tmp3); // tmp10 = tmp0 + tmp3;
00157                 tmp13 = vec_sub(tmp0, tmp3); // tmp13 = tmp0 - tmp3;
00158                 tmp11 = vec_add(tmp1, tmp2); // tmp11 = tmp1 + tmp2;
00159                 tmp12 = vec_sub(tmp1, tmp2); // tmp12 = tmp1 - tmp2;
00160 
00161 
00162                 // dataptr[0] = (DCTELEM) ((tmp10 + tmp11) << PASS1_BITS);
00163                 row0 = vec_add(tmp10, tmp11);
00164 
00165                 // dataptr[4] = (DCTELEM) ((tmp10 - tmp11) << PASS1_BITS);
00166                 row4 = vec_sub(tmp10, tmp11);
00167 
00168 
00169                 // z1 = MULTIPLY(tmp12 + tmp13, FIX_0_541196100);
00170                 z1 = vec_madd(vec_add(tmp12, tmp13), vec_0_541196100, (vector float)zero);
00171 
00172                 // dataptr[2] = (DCTELEM) DESCALE(z1 + MULTIPLY(tmp13, FIX_0_765366865),
00173                 //                                CONST_BITS-PASS1_BITS);
00174                 row2 = vec_madd(tmp13, vec_0_765366865, z1);
00175 
00176                 // dataptr[6] = (DCTELEM) DESCALE(z1 + MULTIPLY(tmp12, - FIX_1_847759065),
00177                 //                                CONST_BITS-PASS1_BITS);
00178                 row6 = vec_madd(tmp12, vec_1_847759065, z1);
00179 
00180                 z1 = vec_add(tmp4, tmp7); // z1 = tmp4 + tmp7;
00181                 z2 = vec_add(tmp5, tmp6); // z2 = tmp5 + tmp6;
00182                 z3 = vec_add(tmp4, tmp6); // z3 = tmp4 + tmp6;
00183                 z4 = vec_add(tmp5, tmp7); // z4 = tmp5 + tmp7;
00184 
00185                 // z5 = MULTIPLY(z3 + z4, FIX_1_175875602); /* sqrt(2) * c3 */
00186                 z5 = vec_madd(vec_add(z3, z4), vec_1_175875602, (vector float)zero);
00187 
00188                 // z3 = MULTIPLY(z3, - FIX_1_961570560); /* sqrt(2) * (-c3-c5) */
00189                 z3 = vec_madd(z3, vec_1_961570560, z5);
00190 
00191                 // z4 = MULTIPLY(z4, - FIX_0_390180644); /* sqrt(2) * (c5-c3) */
00192                 z4 = vec_madd(z4, vec_0_390180644, z5);
00193 
00194                 // The following adds are rolled into the multiplies above
00195                 // z3 = vec_add(z3, z5);  // z3 += z5;
00196                 // z4 = vec_add(z4, z5);  // z4 += z5;
00197 
00198                 // z2 = MULTIPLY(z2, - FIX_2_562915447); /* sqrt(2) * (-c1-c3) */
00199                 // Wow!  It's actually more efficient to roll this multiply
00200                 // into the adds below, even thought the multiply gets done twice!
00201                 // z2 = vec_madd(z2, vec_2_562915447, (vector float)zero);
00202 
00203                 // z1 = MULTIPLY(z1, - FIX_0_899976223); /* sqrt(2) * (c7-c3) */
00204                 // Same with this one...
00205                 // z1 = vec_madd(z1, vec_0_899976223, (vector float)zero);
00206 
00207                 // tmp4 = MULTIPLY(tmp4, FIX_0_298631336); /* sqrt(2) * (-c1+c3+c5-c7) */
00208                 // dataptr[7] = (DCTELEM) DESCALE(tmp4 + z1 + z3, CONST_BITS-PASS1_BITS);
00209                 row7 = vec_madd(tmp4, vec_0_298631336, vec_madd(z1, vec_0_899976223, z3));
00210 
00211                 // tmp5 = MULTIPLY(tmp5, FIX_2_053119869); /* sqrt(2) * ( c1+c3-c5+c7) */
00212                 // dataptr[5] = (DCTELEM) DESCALE(tmp5 + z2 + z4, CONST_BITS-PASS1_BITS);
00213                 row5 = vec_madd(tmp5, vec_2_053119869, vec_madd(z2, vec_2_562915447, z4));
00214 
00215                 // tmp6 = MULTIPLY(tmp6, FIX_3_072711026); /* sqrt(2) * ( c1+c3+c5-c7) */
00216                 // dataptr[3] = (DCTELEM) DESCALE(tmp6 + z2 + z3, CONST_BITS-PASS1_BITS);
00217                 row3 = vec_madd(tmp6, vec_3_072711026, vec_madd(z2, vec_2_562915447, z3));
00218 
00219                 // tmp7 = MULTIPLY(tmp7, FIX_1_501321110); /* sqrt(2) * ( c1+c3-c5-c7) */
00220                 // dataptr[1] = (DCTELEM) DESCALE(tmp7 + z1 + z4, CONST_BITS-PASS1_BITS);
00221                 row1 = vec_madd(z1, vec_0_899976223, vec_madd(tmp7, vec_1_501321110, z4));
00222 
00223                 // Swap the row values with the alts.  If this is the first half,
00224                 // this sets up the low values to be acted on in the second half.
00225                 // If this is the second half, it puts the high values back in
00226                 // the row values where they are expected to be when we're done.
00227                 SWAP(row0, alt0);
00228                 SWAP(row1, alt1);
00229                 SWAP(row2, alt2);
00230                 SWAP(row3, alt3);
00231                 SWAP(row4, alt4);
00232                 SWAP(row5, alt5);
00233                 SWAP(row6, alt6);
00234                 SWAP(row7, alt7);
00235             }
00236 
00237             if (whichPass == 1) {
00238                 // transpose the data for the second pass
00239 
00240                 // First, block transpose the upper right with lower left.
00241                 SWAP(row4, alt0);
00242                 SWAP(row5, alt1);
00243                 SWAP(row6, alt2);
00244                 SWAP(row7, alt3);
00245 
00246                 // Now, transpose each block of four
00247                 TRANSPOSE4(row0, row1, row2, row3);
00248                 TRANSPOSE4(row4, row5, row6, row7);
00249                 TRANSPOSE4(alt0, alt1, alt2, alt3);
00250                 TRANSPOSE4(alt4, alt5, alt6, alt7);
00251             }
00252         }
00253     }
00254 
00255     // perform the quantize step, using the floating point data
00256     // still in the row/alt registers
00257     {
00258         const int* biasAddr;
00259         const vector signed int* qmat;
00260         vector float bias, negBias;
00261 
00262         if (s->mb_intra) {
00263             vector signed int baseVector;
00264 
00265             // We must cache element 0 in the intra case
00266             // (it needs special handling).
00267             baseVector = vec_cts(vec_splat(row0, 0), 0);
00268             vec_ste(baseVector, 0, &oldBaseValue);
00269 
00270             if(n<4){
00271                 qmat = (vector signed int*)s->q_intra_matrix[qscale];
00272                 biasAddr = &s->intra_quant_bias;
00273             }else{
00274                 qmat = (vector signed int*)s->q_chroma_intra_matrix[qscale];
00275                 biasAddr = &s->intra_quant_bias;
00276             }
00277         } else {
00278             qmat = (vector signed int*)s->q_inter_matrix[qscale];
00279             biasAddr = &s->inter_quant_bias;
00280         }
00281 
00282         // Load the bias vector (We add 0.5 to the bias so that we're
00283                                 // rounding when we convert to int, instead of flooring.)
00284         {
00285             vector signed int biasInt;
00286             const vector float negOneFloat = (vector float)FOUROF(-1.0f);
00287             LOAD4(biasInt, biasAddr);
00288             bias = vec_ctf(biasInt, QUANT_BIAS_SHIFT);
00289             negBias = vec_madd(bias, negOneFloat, zero);
00290         }
00291 
00292         {
00293             vector float q0, q1, q2, q3, q4, q5, q6, q7;
00294 
00295             q0 = vec_ctf(qmat[0], QMAT_SHIFT);
00296             q1 = vec_ctf(qmat[2], QMAT_SHIFT);
00297             q2 = vec_ctf(qmat[4], QMAT_SHIFT);
00298             q3 = vec_ctf(qmat[6], QMAT_SHIFT);
00299             q4 = vec_ctf(qmat[8], QMAT_SHIFT);
00300             q5 = vec_ctf(qmat[10], QMAT_SHIFT);
00301             q6 = vec_ctf(qmat[12], QMAT_SHIFT);
00302             q7 = vec_ctf(qmat[14], QMAT_SHIFT);
00303 
00304             row0 = vec_sel(vec_madd(row0, q0, negBias), vec_madd(row0, q0, bias),
00305                     vec_cmpgt(row0, zero));
00306             row1 = vec_sel(vec_madd(row1, q1, negBias), vec_madd(row1, q1, bias),
00307                     vec_cmpgt(row1, zero));
00308             row2 = vec_sel(vec_madd(row2, q2, negBias), vec_madd(row2, q2, bias),
00309                     vec_cmpgt(row2, zero));
00310             row3 = vec_sel(vec_madd(row3, q3, negBias), vec_madd(row3, q3, bias),
00311                     vec_cmpgt(row3, zero));
00312             row4 = vec_sel(vec_madd(row4, q4, negBias), vec_madd(row4, q4, bias),
00313                     vec_cmpgt(row4, zero));
00314             row5 = vec_sel(vec_madd(row5, q5, negBias), vec_madd(row5, q5, bias),
00315                     vec_cmpgt(row5, zero));
00316             row6 = vec_sel(vec_madd(row6, q6, negBias), vec_madd(row6, q6, bias),
00317                     vec_cmpgt(row6, zero));
00318             row7 = vec_sel(vec_madd(row7, q7, negBias), vec_madd(row7, q7, bias),
00319                     vec_cmpgt(row7, zero));
00320 
00321             q0 = vec_ctf(qmat[1], QMAT_SHIFT);
00322             q1 = vec_ctf(qmat[3], QMAT_SHIFT);
00323             q2 = vec_ctf(qmat[5], QMAT_SHIFT);
00324             q3 = vec_ctf(qmat[7], QMAT_SHIFT);
00325             q4 = vec_ctf(qmat[9], QMAT_SHIFT);
00326             q5 = vec_ctf(qmat[11], QMAT_SHIFT);
00327             q6 = vec_ctf(qmat[13], QMAT_SHIFT);
00328             q7 = vec_ctf(qmat[15], QMAT_SHIFT);
00329 
00330             alt0 = vec_sel(vec_madd(alt0, q0, negBias), vec_madd(alt0, q0, bias),
00331                     vec_cmpgt(alt0, zero));
00332             alt1 = vec_sel(vec_madd(alt1, q1, negBias), vec_madd(alt1, q1, bias),
00333                     vec_cmpgt(alt1, zero));
00334             alt2 = vec_sel(vec_madd(alt2, q2, negBias), vec_madd(alt2, q2, bias),
00335                     vec_cmpgt(alt2, zero));
00336             alt3 = vec_sel(vec_madd(alt3, q3, negBias), vec_madd(alt3, q3, bias),
00337                     vec_cmpgt(alt3, zero));
00338             alt4 = vec_sel(vec_madd(alt4, q4, negBias), vec_madd(alt4, q4, bias),
00339                     vec_cmpgt(alt4, zero));
00340             alt5 = vec_sel(vec_madd(alt5, q5, negBias), vec_madd(alt5, q5, bias),
00341                     vec_cmpgt(alt5, zero));
00342             alt6 = vec_sel(vec_madd(alt6, q6, negBias), vec_madd(alt6, q6, bias),
00343                     vec_cmpgt(alt6, zero));
00344             alt7 = vec_sel(vec_madd(alt7, q7, negBias), vec_madd(alt7, q7, bias),
00345                     vec_cmpgt(alt7, zero));
00346         }
00347 
00348 
00349     }
00350 
00351     // Store the data back into the original block
00352     {
00353         vector signed short data0, data1, data2, data3, data4, data5, data6, data7;
00354 
00355         data0 = vec_pack(vec_cts(row0, 0), vec_cts(alt0, 0));
00356         data1 = vec_pack(vec_cts(row1, 0), vec_cts(alt1, 0));
00357         data2 = vec_pack(vec_cts(row2, 0), vec_cts(alt2, 0));
00358         data3 = vec_pack(vec_cts(row3, 0), vec_cts(alt3, 0));
00359         data4 = vec_pack(vec_cts(row4, 0), vec_cts(alt4, 0));
00360         data5 = vec_pack(vec_cts(row5, 0), vec_cts(alt5, 0));
00361         data6 = vec_pack(vec_cts(row6, 0), vec_cts(alt6, 0));
00362         data7 = vec_pack(vec_cts(row7, 0), vec_cts(alt7, 0));
00363 
00364         {
00365             // Clamp for overflow
00366             vector signed int max_q_int, min_q_int;
00367             vector signed short max_q, min_q;
00368 
00369             LOAD4(max_q_int, &s->max_qcoeff);
00370             LOAD4(min_q_int, &s->min_qcoeff);
00371 
00372             max_q = vec_pack(max_q_int, max_q_int);
00373             min_q = vec_pack(min_q_int, min_q_int);
00374 
00375             data0 = vec_max(vec_min(data0, max_q), min_q);
00376             data1 = vec_max(vec_min(data1, max_q), min_q);
00377             data2 = vec_max(vec_min(data2, max_q), min_q);
00378             data4 = vec_max(vec_min(data4, max_q), min_q);
00379             data5 = vec_max(vec_min(data5, max_q), min_q);
00380             data6 = vec_max(vec_min(data6, max_q), min_q);
00381             data7 = vec_max(vec_min(data7, max_q), min_q);
00382         }
00383 
00384         {
00385         vector bool char zero_01, zero_23, zero_45, zero_67;
00386         vector signed char scanIndexes_01, scanIndexes_23, scanIndexes_45, scanIndexes_67;
00387         vector signed char negOne = vec_splat_s8(-1);
00388         vector signed char* scanPtr =
00389                 (vector signed char*)(s->intra_scantable.inverse);
00390         signed char lastNonZeroChar;
00391 
00392         // Determine the largest non-zero index.
00393         zero_01 = vec_pack(vec_cmpeq(data0, (vector signed short)zero),
00394                 vec_cmpeq(data1, (vector signed short)zero));
00395         zero_23 = vec_pack(vec_cmpeq(data2, (vector signed short)zero),
00396                 vec_cmpeq(data3, (vector signed short)zero));
00397         zero_45 = vec_pack(vec_cmpeq(data4, (vector signed short)zero),
00398                 vec_cmpeq(data5, (vector signed short)zero));
00399         zero_67 = vec_pack(vec_cmpeq(data6, (vector signed short)zero),
00400                 vec_cmpeq(data7, (vector signed short)zero));
00401 
00402         // 64 biggest values
00403         scanIndexes_01 = vec_sel(scanPtr[0], negOne, zero_01);
00404         scanIndexes_23 = vec_sel(scanPtr[1], negOne, zero_23);
00405         scanIndexes_45 = vec_sel(scanPtr[2], negOne, zero_45);
00406         scanIndexes_67 = vec_sel(scanPtr[3], negOne, zero_67);
00407 
00408         // 32 largest values
00409         scanIndexes_01 = vec_max(scanIndexes_01, scanIndexes_23);
00410         scanIndexes_45 = vec_max(scanIndexes_45, scanIndexes_67);
00411 
00412         // 16 largest values
00413         scanIndexes_01 = vec_max(scanIndexes_01, scanIndexes_45);
00414 
00415         // 8 largest values
00416         scanIndexes_01 = vec_max(vec_mergeh(scanIndexes_01, negOne),
00417                 vec_mergel(scanIndexes_01, negOne));
00418 
00419         // 4 largest values
00420         scanIndexes_01 = vec_max(vec_mergeh(scanIndexes_01, negOne),
00421                 vec_mergel(scanIndexes_01, negOne));
00422 
00423         // 2 largest values
00424         scanIndexes_01 = vec_max(vec_mergeh(scanIndexes_01, negOne),
00425                 vec_mergel(scanIndexes_01, negOne));
00426 
00427         // largest value
00428         scanIndexes_01 = vec_max(vec_mergeh(scanIndexes_01, negOne),
00429                 vec_mergel(scanIndexes_01, negOne));
00430 
00431         scanIndexes_01 = vec_splat(scanIndexes_01, 0);
00432 
00433 
00434         vec_ste(scanIndexes_01, 0, &lastNonZeroChar);
00435 
00436         lastNonZero = lastNonZeroChar;
00437 
00438         // While the data is still in vectors we check for the transpose IDCT permute
00439         // and handle it using the vector unit if we can.  This is the permute used
00440         // by the altivec idct, so it is common when using the altivec dct.
00441 
00442         if ((lastNonZero > 0) && (s->dsp.idct_permutation_type == FF_TRANSPOSE_IDCT_PERM)) {
00443             TRANSPOSE8(data0, data1, data2, data3, data4, data5, data6, data7);
00444         }
00445 
00446         vec_st(data0, 0, data);
00447         vec_st(data1, 16, data);
00448         vec_st(data2, 32, data);
00449         vec_st(data3, 48, data);
00450         vec_st(data4, 64, data);
00451         vec_st(data5, 80, data);
00452         vec_st(data6, 96, data);
00453         vec_st(data7, 112, data);
00454         }
00455     }
00456 
00457     // special handling of block[0]
00458     if (s->mb_intra) {
00459         if (!s->h263_aic) {
00460             if (n < 4)
00461                 oldBaseValue /= s->y_dc_scale;
00462             else
00463                 oldBaseValue /= s->c_dc_scale;
00464         }
00465 
00466         // Divide by 8, rounding the result
00467         data[0] = (oldBaseValue + 4) >> 3;
00468     }
00469 
00470     // We handled the transpose permutation above and we don't
00471     // need to permute the "no" permutation case.
00472     if ((lastNonZero > 0) &&
00473         (s->dsp.idct_permutation_type != FF_TRANSPOSE_IDCT_PERM) &&
00474         (s->dsp.idct_permutation_type != FF_NO_IDCT_PERM)) {
00475         ff_block_permute(data, s->dsp.idct_permutation,
00476                 s->intra_scantable.scantable, lastNonZero);
00477     }
00478 
00479     return lastNonZero;
00480 }
00481 
00482 /* AltiVec version of dct_unquantize_h263
00483    this code assumes `block' is 16 bytes-aligned */
00484 static void dct_unquantize_h263_altivec(MpegEncContext *s,
00485                                  DCTELEM *block, int n, int qscale)
00486 {
00487     int i, level, qmul, qadd;
00488     int nCoeffs;
00489 
00490     assert(s->block_last_index[n]>=0);
00491 
00492     qadd = (qscale - 1) | 1;
00493     qmul = qscale << 1;
00494 
00495     if (s->mb_intra) {
00496         if (!s->h263_aic) {
00497             if (n < 4)
00498                 block[0] = block[0] * s->y_dc_scale;
00499             else
00500                 block[0] = block[0] * s->c_dc_scale;
00501         }else
00502             qadd = 0;
00503         i = 1;
00504         nCoeffs= 63; //does not always use zigzag table
00505     } else {
00506         i = 0;
00507         nCoeffs= s->intra_scantable.raster_end[ s->block_last_index[n] ];
00508     }
00509 
00510     {
00511         register const vector signed short vczero = (const vector signed short)vec_splat_s16(0);
00512         DECLARE_ALIGNED(16, short, qmul8) = qmul;
00513         DECLARE_ALIGNED(16, short, qadd8) = qadd;
00514         register vector signed short blockv, qmulv, qaddv, nqaddv, temp1;
00515         register vector bool short blockv_null, blockv_neg;
00516         register short backup_0 = block[0];
00517         register int j = 0;
00518 
00519         qmulv = vec_splat((vec_s16)vec_lde(0, &qmul8), 0);
00520         qaddv = vec_splat((vec_s16)vec_lde(0, &qadd8), 0);
00521         nqaddv = vec_sub(vczero, qaddv);
00522 
00523         // vectorize all the 16 bytes-aligned blocks
00524         // of 8 elements
00525         for(; (j + 7) <= nCoeffs ; j+=8) {
00526             blockv = vec_ld(j << 1, block);
00527             blockv_neg = vec_cmplt(blockv, vczero);
00528             blockv_null = vec_cmpeq(blockv, vczero);
00529             // choose between +qadd or -qadd as the third operand
00530             temp1 = vec_sel(qaddv, nqaddv, blockv_neg);
00531             // multiply & add (block{i,i+7} * qmul [+-] qadd)
00532             temp1 = vec_mladd(blockv, qmulv, temp1);
00533             // put 0 where block[{i,i+7} used to have 0
00534             blockv = vec_sel(temp1, blockv, blockv_null);
00535             vec_st(blockv, j << 1, block);
00536         }
00537 
00538         // if nCoeffs isn't a multiple of 8, finish the job
00539         // using good old scalar units.
00540         // (we could do it using a truncated vector,
00541         // but I'm not sure it's worth the hassle)
00542         for(; j <= nCoeffs ; j++) {
00543             level = block[j];
00544             if (level) {
00545                 if (level < 0) {
00546                     level = level * qmul - qadd;
00547                 } else {
00548                     level = level * qmul + qadd;
00549                 }
00550                 block[j] = level;
00551             }
00552         }
00553 
00554         if (i == 1) {
00555             // cheat. this avoid special-casing the first iteration
00556             block[0] = backup_0;
00557         }
00558     }
00559 }
00560 
00561 
00562 void MPV_common_init_altivec(MpegEncContext *s)
00563 {
00564     if (!(av_get_cpu_flags() & AV_CPU_FLAG_ALTIVEC)) return;
00565 
00566     // Test to make sure that the dct required alignments are met.
00567     if ((((long)(s->q_intra_matrix) & 0x0f) != 0) ||
00568         (((long)(s->q_inter_matrix) & 0x0f) != 0)) {
00569         av_log(s->avctx, AV_LOG_INFO, "Internal Error: q-matrix blocks must be 16-byte aligned "
00570                 "to use AltiVec DCT. Reverting to non-AltiVec version.\n");
00571         return;
00572     }
00573 
00574     if (((long)(s->intra_scantable.inverse) & 0x0f) != 0) {
00575         av_log(s->avctx, AV_LOG_INFO, "Internal Error: scan table blocks must be 16-byte aligned "
00576                 "to use AltiVec DCT. Reverting to non-AltiVec version.\n");
00577         return;
00578     }
00579 
00580 
00581     if ((s->avctx->dct_algo == FF_DCT_AUTO) ||
00582             (s->avctx->dct_algo == FF_DCT_ALTIVEC)) {
00583         s->dct_unquantize_h263_intra = dct_unquantize_h263_altivec;
00584         s->dct_unquantize_h263_inter = dct_unquantize_h263_altivec;
00585     }
00586 }
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