2 * Copyright (c) 2002 Dieter Shirley
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with this library; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 #include "../dsputil.h"
22 #include "../mpegvideo.h"
24 #include "gcc_fixes.h"
26 #include "dsputil_altivec.h"
28 // Swaps two variables (used for altivec registers)
31 __typeof__(a) swap_temp=a; \
36 // transposes a matrix consisting of four vectors with four elements each
37 #define TRANSPOSE4(a,b,c,d) \
39 __typeof__(a) _trans_ach = vec_mergeh(a, c); \
40 __typeof__(a) _trans_acl = vec_mergel(a, c); \
41 __typeof__(a) _trans_bdh = vec_mergeh(b, d); \
42 __typeof__(a) _trans_bdl = vec_mergel(b, d); \
44 a = vec_mergeh(_trans_ach, _trans_bdh); \
45 b = vec_mergel(_trans_ach, _trans_bdh); \
46 c = vec_mergeh(_trans_acl, _trans_bdl); \
47 d = vec_mergel(_trans_acl, _trans_bdl); \
50 #define TRANSPOSE8(a,b,c,d,e,f,g,h) \
52 __typeof__(a) _A1, _B1, _C1, _D1, _E1, _F1, _G1, _H1; \
53 __typeof__(a) _A2, _B2, _C2, _D2, _E2, _F2, _G2, _H2; \
55 _A1 = vec_mergeh (a, e); \
56 _B1 = vec_mergel (a, e); \
57 _C1 = vec_mergeh (b, f); \
58 _D1 = vec_mergel (b, f); \
59 _E1 = vec_mergeh (c, g); \
60 _F1 = vec_mergel (c, g); \
61 _G1 = vec_mergeh (d, h); \
62 _H1 = vec_mergel (d, h); \
64 _A2 = vec_mergeh (_A1, _E1); \
65 _B2 = vec_mergel (_A1, _E1); \
66 _C2 = vec_mergeh (_B1, _F1); \
67 _D2 = vec_mergel (_B1, _F1); \
68 _E2 = vec_mergeh (_C1, _G1); \
69 _F2 = vec_mergel (_C1, _G1); \
70 _G2 = vec_mergeh (_D1, _H1); \
71 _H2 = vec_mergel (_D1, _H1); \
73 a = vec_mergeh (_A2, _E2); \
74 b = vec_mergel (_A2, _E2); \
75 c = vec_mergeh (_B2, _F2); \
76 d = vec_mergel (_B2, _F2); \
77 e = vec_mergeh (_C2, _G2); \
78 f = vec_mergel (_C2, _G2); \
79 g = vec_mergeh (_D2, _H2); \
80 h = vec_mergel (_D2, _H2); \
84 // Loads a four-byte value (int or float) from the target address
85 // into every element in the target vector. Only works if the
86 // target address is four-byte aligned (which should be always).
87 #define LOAD4(vec, address) \
89 __typeof__(vec)* _load_addr = (__typeof__(vec)*)(address); \
90 vector unsigned char _perm_vec = vec_lvsl(0,(address)); \
91 vec = vec_ld(0, _load_addr); \
92 vec = vec_perm(vec, vec, _perm_vec); \
93 vec = vec_splat(vec, 0); \
100 // slower, for dumb non-apple GCC
101 #define FOUROF(a) {a,a,a,a}
103 int dct_quantize_altivec(MpegEncContext* s,
104 DCTELEM* data, int n,
105 int qscale, int* overflow)
108 vector float row0, row1, row2, row3, row4, row5, row6, row7;
109 vector float alt0, alt1, alt2, alt3, alt4, alt5, alt6, alt7;
110 const_vector float zero = (const_vector float)FOUROF(0.);
111 // used after quantise step
112 int oldBaseValue = 0;
114 // Load the data into the row/alt vectors
116 vector signed short data0, data1, data2, data3, data4, data5, data6, data7;
118 data0 = vec_ld(0, data);
119 data1 = vec_ld(16, data);
120 data2 = vec_ld(32, data);
121 data3 = vec_ld(48, data);
122 data4 = vec_ld(64, data);
123 data5 = vec_ld(80, data);
124 data6 = vec_ld(96, data);
125 data7 = vec_ld(112, data);
127 // Transpose the data before we start
128 TRANSPOSE8(data0, data1, data2, data3, data4, data5, data6, data7);
130 // load the data into floating point vectors. We load
131 // the high half of each row into the main row vectors
132 // and the low half into the alt vectors.
133 row0 = vec_ctf(vec_unpackh(data0), 0);
134 alt0 = vec_ctf(vec_unpackl(data0), 0);
135 row1 = vec_ctf(vec_unpackh(data1), 0);
136 alt1 = vec_ctf(vec_unpackl(data1), 0);
137 row2 = vec_ctf(vec_unpackh(data2), 0);
138 alt2 = vec_ctf(vec_unpackl(data2), 0);
139 row3 = vec_ctf(vec_unpackh(data3), 0);
140 alt3 = vec_ctf(vec_unpackl(data3), 0);
141 row4 = vec_ctf(vec_unpackh(data4), 0);
142 alt4 = vec_ctf(vec_unpackl(data4), 0);
143 row5 = vec_ctf(vec_unpackh(data5), 0);
144 alt5 = vec_ctf(vec_unpackl(data5), 0);
145 row6 = vec_ctf(vec_unpackh(data6), 0);
146 alt6 = vec_ctf(vec_unpackl(data6), 0);
147 row7 = vec_ctf(vec_unpackh(data7), 0);
148 alt7 = vec_ctf(vec_unpackl(data7), 0);
151 // The following block could exist as a separate an altivec dct
152 // function. However, if we put it inline, the DCT data can remain
153 // in the vector local variables, as floats, which we'll use during the
156 const vector float vec_0_298631336 = (vector float)FOUROF(0.298631336f);
157 const vector float vec_0_390180644 = (vector float)FOUROF(-0.390180644f);
158 const vector float vec_0_541196100 = (vector float)FOUROF(0.541196100f);
159 const vector float vec_0_765366865 = (vector float)FOUROF(0.765366865f);
160 const vector float vec_0_899976223 = (vector float)FOUROF(-0.899976223f);
161 const vector float vec_1_175875602 = (vector float)FOUROF(1.175875602f);
162 const vector float vec_1_501321110 = (vector float)FOUROF(1.501321110f);
163 const vector float vec_1_847759065 = (vector float)FOUROF(-1.847759065f);
164 const vector float vec_1_961570560 = (vector float)FOUROF(-1.961570560f);
165 const vector float vec_2_053119869 = (vector float)FOUROF(2.053119869f);
166 const vector float vec_2_562915447 = (vector float)FOUROF(-2.562915447f);
167 const vector float vec_3_072711026 = (vector float)FOUROF(3.072711026f);
170 int whichPass, whichHalf;
172 for(whichPass = 1; whichPass<=2; whichPass++)
174 for(whichHalf = 1; whichHalf<=2; whichHalf++)
176 vector float tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
177 vector float tmp10, tmp11, tmp12, tmp13;
178 vector float z1, z2, z3, z4, z5;
180 tmp0 = vec_add(row0, row7); // tmp0 = dataptr[0] + dataptr[7];
181 tmp7 = vec_sub(row0, row7); // tmp7 = dataptr[0] - dataptr[7];
182 tmp3 = vec_add(row3, row4); // tmp3 = dataptr[3] + dataptr[4];
183 tmp4 = vec_sub(row3, row4); // tmp4 = dataptr[3] - dataptr[4];
184 tmp1 = vec_add(row1, row6); // tmp1 = dataptr[1] + dataptr[6];
185 tmp6 = vec_sub(row1, row6); // tmp6 = dataptr[1] - dataptr[6];
186 tmp2 = vec_add(row2, row5); // tmp2 = dataptr[2] + dataptr[5];
187 tmp5 = vec_sub(row2, row5); // tmp5 = dataptr[2] - dataptr[5];
189 tmp10 = vec_add(tmp0, tmp3); // tmp10 = tmp0 + tmp3;
190 tmp13 = vec_sub(tmp0, tmp3); // tmp13 = tmp0 - tmp3;
191 tmp11 = vec_add(tmp1, tmp2); // tmp11 = tmp1 + tmp2;
192 tmp12 = vec_sub(tmp1, tmp2); // tmp12 = tmp1 - tmp2;
195 // dataptr[0] = (DCTELEM) ((tmp10 + tmp11) << PASS1_BITS);
196 row0 = vec_add(tmp10, tmp11);
198 // dataptr[4] = (DCTELEM) ((tmp10 - tmp11) << PASS1_BITS);
199 row4 = vec_sub(tmp10, tmp11);
202 // z1 = MULTIPLY(tmp12 + tmp13, FIX_0_541196100);
203 z1 = vec_madd(vec_add(tmp12, tmp13), vec_0_541196100, (vector float)zero);
205 // dataptr[2] = (DCTELEM) DESCALE(z1 + MULTIPLY(tmp13, FIX_0_765366865),
206 // CONST_BITS-PASS1_BITS);
207 row2 = vec_madd(tmp13, vec_0_765366865, z1);
209 // dataptr[6] = (DCTELEM) DESCALE(z1 + MULTIPLY(tmp12, - FIX_1_847759065),
210 // CONST_BITS-PASS1_BITS);
211 row6 = vec_madd(tmp12, vec_1_847759065, z1);
213 z1 = vec_add(tmp4, tmp7); // z1 = tmp4 + tmp7;
214 z2 = vec_add(tmp5, tmp6); // z2 = tmp5 + tmp6;
215 z3 = vec_add(tmp4, tmp6); // z3 = tmp4 + tmp6;
216 z4 = vec_add(tmp5, tmp7); // z4 = tmp5 + tmp7;
218 // z5 = MULTIPLY(z3 + z4, FIX_1_175875602); /* sqrt(2) * c3 */
219 z5 = vec_madd(vec_add(z3, z4), vec_1_175875602, (vector float)zero);
221 // z3 = MULTIPLY(z3, - FIX_1_961570560); /* sqrt(2) * (-c3-c5) */
222 z3 = vec_madd(z3, vec_1_961570560, z5);
224 // z4 = MULTIPLY(z4, - FIX_0_390180644); /* sqrt(2) * (c5-c3) */
225 z4 = vec_madd(z4, vec_0_390180644, z5);
227 // The following adds are rolled into the multiplies above
228 // z3 = vec_add(z3, z5); // z3 += z5;
229 // z4 = vec_add(z4, z5); // z4 += z5;
231 // z2 = MULTIPLY(z2, - FIX_2_562915447); /* sqrt(2) * (-c1-c3) */
232 // Wow! It's actually more effecient to roll this multiply
233 // into the adds below, even thought the multiply gets done twice!
234 // z2 = vec_madd(z2, vec_2_562915447, (vector float)zero);
236 // z1 = MULTIPLY(z1, - FIX_0_899976223); /* sqrt(2) * (c7-c3) */
237 // Same with this one...
238 // z1 = vec_madd(z1, vec_0_899976223, (vector float)zero);
240 // tmp4 = MULTIPLY(tmp4, FIX_0_298631336); /* sqrt(2) * (-c1+c3+c5-c7) */
241 // dataptr[7] = (DCTELEM) DESCALE(tmp4 + z1 + z3, CONST_BITS-PASS1_BITS);
242 row7 = vec_madd(tmp4, vec_0_298631336, vec_madd(z1, vec_0_899976223, z3));
244 // tmp5 = MULTIPLY(tmp5, FIX_2_053119869); /* sqrt(2) * ( c1+c3-c5+c7) */
245 // dataptr[5] = (DCTELEM) DESCALE(tmp5 + z2 + z4, CONST_BITS-PASS1_BITS);
246 row5 = vec_madd(tmp5, vec_2_053119869, vec_madd(z2, vec_2_562915447, z4));
248 // tmp6 = MULTIPLY(tmp6, FIX_3_072711026); /* sqrt(2) * ( c1+c3+c5-c7) */
249 // dataptr[3] = (DCTELEM) DESCALE(tmp6 + z2 + z3, CONST_BITS-PASS1_BITS);
250 row3 = vec_madd(tmp6, vec_3_072711026, vec_madd(z2, vec_2_562915447, z3));
252 // tmp7 = MULTIPLY(tmp7, FIX_1_501321110); /* sqrt(2) * ( c1+c3-c5-c7) */
253 // dataptr[1] = (DCTELEM) DESCALE(tmp7 + z1 + z4, CONST_BITS-PASS1_BITS);
254 row1 = vec_madd(z1, vec_0_899976223, vec_madd(tmp7, vec_1_501321110, z4));
256 // Swap the row values with the alts. If this is the first half,
257 // this sets up the low values to be acted on in the second half.
258 // If this is the second half, it puts the high values back in
259 // the row values where they are expected to be when we're done.
272 // transpose the data for the second pass
274 // First, block transpose the upper right with lower left.
280 // Now, transpose each block of four
281 TRANSPOSE4(row0, row1, row2, row3);
282 TRANSPOSE4(row4, row5, row6, row7);
283 TRANSPOSE4(alt0, alt1, alt2, alt3);
284 TRANSPOSE4(alt4, alt5, alt6, alt7);
289 // perform the quantise step, using the floating point data
290 // still in the row/alt registers
293 const vector signed int* qmat;
294 vector float bias, negBias;
298 vector signed int baseVector;
300 // We must cache element 0 in the intra case
301 // (it needs special handling).
302 baseVector = vec_cts(vec_splat(row0, 0), 0);
303 vec_ste(baseVector, 0, &oldBaseValue);
305 qmat = (vector signed int*)s->q_intra_matrix[qscale];
306 biasAddr = &(s->intra_quant_bias);
310 qmat = (vector signed int*)s->q_inter_matrix[qscale];
311 biasAddr = &(s->inter_quant_bias);
314 // Load the bias vector (We add 0.5 to the bias so that we're
315 // rounding when we convert to int, instead of flooring.)
317 vector signed int biasInt;
318 const vector float negOneFloat = (vector float)FOUROF(-1.0f);
319 LOAD4(biasInt, biasAddr);
320 bias = vec_ctf(biasInt, QUANT_BIAS_SHIFT);
321 negBias = vec_madd(bias, negOneFloat, zero);
325 vector float q0, q1, q2, q3, q4, q5, q6, q7;
327 q0 = vec_ctf(qmat[0], QMAT_SHIFT);
328 q1 = vec_ctf(qmat[2], QMAT_SHIFT);
329 q2 = vec_ctf(qmat[4], QMAT_SHIFT);
330 q3 = vec_ctf(qmat[6], QMAT_SHIFT);
331 q4 = vec_ctf(qmat[8], QMAT_SHIFT);
332 q5 = vec_ctf(qmat[10], QMAT_SHIFT);
333 q6 = vec_ctf(qmat[12], QMAT_SHIFT);
334 q7 = vec_ctf(qmat[14], QMAT_SHIFT);
336 row0 = vec_sel(vec_madd(row0, q0, negBias), vec_madd(row0, q0, bias),
337 vec_cmpgt(row0, zero));
338 row1 = vec_sel(vec_madd(row1, q1, negBias), vec_madd(row1, q1, bias),
339 vec_cmpgt(row1, zero));
340 row2 = vec_sel(vec_madd(row2, q2, negBias), vec_madd(row2, q2, bias),
341 vec_cmpgt(row2, zero));
342 row3 = vec_sel(vec_madd(row3, q3, negBias), vec_madd(row3, q3, bias),
343 vec_cmpgt(row3, zero));
344 row4 = vec_sel(vec_madd(row4, q4, negBias), vec_madd(row4, q4, bias),
345 vec_cmpgt(row4, zero));
346 row5 = vec_sel(vec_madd(row5, q5, negBias), vec_madd(row5, q5, bias),
347 vec_cmpgt(row5, zero));
348 row6 = vec_sel(vec_madd(row6, q6, negBias), vec_madd(row6, q6, bias),
349 vec_cmpgt(row6, zero));
350 row7 = vec_sel(vec_madd(row7, q7, negBias), vec_madd(row7, q7, bias),
351 vec_cmpgt(row7, zero));
353 q0 = vec_ctf(qmat[1], QMAT_SHIFT);
354 q1 = vec_ctf(qmat[3], QMAT_SHIFT);
355 q2 = vec_ctf(qmat[5], QMAT_SHIFT);
356 q3 = vec_ctf(qmat[7], QMAT_SHIFT);
357 q4 = vec_ctf(qmat[9], QMAT_SHIFT);
358 q5 = vec_ctf(qmat[11], QMAT_SHIFT);
359 q6 = vec_ctf(qmat[13], QMAT_SHIFT);
360 q7 = vec_ctf(qmat[15], QMAT_SHIFT);
362 alt0 = vec_sel(vec_madd(alt0, q0, negBias), vec_madd(alt0, q0, bias),
363 vec_cmpgt(alt0, zero));
364 alt1 = vec_sel(vec_madd(alt1, q1, negBias), vec_madd(alt1, q1, bias),
365 vec_cmpgt(alt1, zero));
366 alt2 = vec_sel(vec_madd(alt2, q2, negBias), vec_madd(alt2, q2, bias),
367 vec_cmpgt(alt2, zero));
368 alt3 = vec_sel(vec_madd(alt3, q3, negBias), vec_madd(alt3, q3, bias),
369 vec_cmpgt(alt3, zero));
370 alt4 = vec_sel(vec_madd(alt4, q4, negBias), vec_madd(alt4, q4, bias),
371 vec_cmpgt(alt4, zero));
372 alt5 = vec_sel(vec_madd(alt5, q5, negBias), vec_madd(alt5, q5, bias),
373 vec_cmpgt(alt5, zero));
374 alt6 = vec_sel(vec_madd(alt6, q6, negBias), vec_madd(alt6, q6, bias),
375 vec_cmpgt(alt6, zero));
376 alt7 = vec_sel(vec_madd(alt7, q7, negBias), vec_madd(alt7, q7, bias),
377 vec_cmpgt(alt7, zero));
383 // Store the data back into the original block
385 vector signed short data0, data1, data2, data3, data4, data5, data6, data7;
387 data0 = vec_pack(vec_cts(row0, 0), vec_cts(alt0, 0));
388 data1 = vec_pack(vec_cts(row1, 0), vec_cts(alt1, 0));
389 data2 = vec_pack(vec_cts(row2, 0), vec_cts(alt2, 0));
390 data3 = vec_pack(vec_cts(row3, 0), vec_cts(alt3, 0));
391 data4 = vec_pack(vec_cts(row4, 0), vec_cts(alt4, 0));
392 data5 = vec_pack(vec_cts(row5, 0), vec_cts(alt5, 0));
393 data6 = vec_pack(vec_cts(row6, 0), vec_cts(alt6, 0));
394 data7 = vec_pack(vec_cts(row7, 0), vec_cts(alt7, 0));
397 // Clamp for overflow
398 vector signed int max_q_int, min_q_int;
399 vector signed short max_q, min_q;
401 LOAD4(max_q_int, &(s->max_qcoeff));
402 LOAD4(min_q_int, &(s->min_qcoeff));
404 max_q = vec_pack(max_q_int, max_q_int);
405 min_q = vec_pack(min_q_int, min_q_int);
407 data0 = vec_max(vec_min(data0, max_q), min_q);
408 data1 = vec_max(vec_min(data1, max_q), min_q);
409 data2 = vec_max(vec_min(data2, max_q), min_q);
410 data4 = vec_max(vec_min(data4, max_q), min_q);
411 data5 = vec_max(vec_min(data5, max_q), min_q);
412 data6 = vec_max(vec_min(data6, max_q), min_q);
413 data7 = vec_max(vec_min(data7, max_q), min_q);
417 vector bool char zero_01, zero_23, zero_45, zero_67;
418 vector signed char scanIndices_01, scanIndices_23, scanIndices_45, scanIndices_67;
419 vector signed char negOne = vec_splat_s8(-1);
420 vector signed char* scanPtr =
421 (vector signed char*)(s->intra_scantable.inverse);
422 signed char lastNonZeroChar;
424 // Determine the largest non-zero index.
425 zero_01 = vec_pack(vec_cmpeq(data0, (vector signed short)zero),
426 vec_cmpeq(data1, (vector signed short)zero));
427 zero_23 = vec_pack(vec_cmpeq(data2, (vector signed short)zero),
428 vec_cmpeq(data3, (vector signed short)zero));
429 zero_45 = vec_pack(vec_cmpeq(data4, (vector signed short)zero),
430 vec_cmpeq(data5, (vector signed short)zero));
431 zero_67 = vec_pack(vec_cmpeq(data6, (vector signed short)zero),
432 vec_cmpeq(data7, (vector signed short)zero));
435 scanIndices_01 = vec_sel(scanPtr[0], negOne, zero_01);
436 scanIndices_23 = vec_sel(scanPtr[1], negOne, zero_23);
437 scanIndices_45 = vec_sel(scanPtr[2], negOne, zero_45);
438 scanIndices_67 = vec_sel(scanPtr[3], negOne, zero_67);
441 scanIndices_01 = vec_max(scanIndices_01, scanIndices_23);
442 scanIndices_45 = vec_max(scanIndices_45, scanIndices_67);
445 scanIndices_01 = vec_max(scanIndices_01, scanIndices_45);
448 scanIndices_01 = vec_max(vec_mergeh(scanIndices_01, negOne),
449 vec_mergel(scanIndices_01, negOne));
452 scanIndices_01 = vec_max(vec_mergeh(scanIndices_01, negOne),
453 vec_mergel(scanIndices_01, negOne));
456 scanIndices_01 = vec_max(vec_mergeh(scanIndices_01, negOne),
457 vec_mergel(scanIndices_01, negOne));
460 scanIndices_01 = vec_max(vec_mergeh(scanIndices_01, negOne),
461 vec_mergel(scanIndices_01, negOne));
463 scanIndices_01 = vec_splat(scanIndices_01, 0);
466 vec_ste(scanIndices_01, 0, &lastNonZeroChar);
468 lastNonZero = lastNonZeroChar;
470 // While the data is still in vectors we check for the transpose IDCT permute
471 // and handle it using the vector unit if we can. This is the permute used
472 // by the altivec idct, so it is common when using the altivec dct.
474 if ((lastNonZero > 0) && (s->dsp.idct_permutation_type == FF_TRANSPOSE_IDCT_PERM))
476 TRANSPOSE8(data0, data1, data2, data3, data4, data5, data6, data7);
479 vec_st(data0, 0, data);
480 vec_st(data1, 16, data);
481 vec_st(data2, 32, data);
482 vec_st(data3, 48, data);
483 vec_st(data4, 64, data);
484 vec_st(data5, 80, data);
485 vec_st(data6, 96, data);
486 vec_st(data7, 112, data);
490 // special handling of block[0]
496 oldBaseValue /= s->y_dc_scale;
498 oldBaseValue /= s->c_dc_scale;
501 // Divide by 8, rounding the result
502 data[0] = (oldBaseValue + 4) >> 3;
505 // We handled the tranpose permutation above and we don't
506 // need to permute the "no" permutation case.
507 if ((lastNonZero > 0) &&
508 (s->dsp.idct_permutation_type != FF_TRANSPOSE_IDCT_PERM) &&
509 (s->dsp.idct_permutation_type != FF_NO_IDCT_PERM))
511 ff_block_permute(data, s->dsp.idct_permutation,
512 s->intra_scantable.scantable, lastNonZero);
520 AltiVec version of dct_unquantize_h263
521 this code assumes `block' is 16 bytes-aligned
523 void dct_unquantize_h263_altivec(MpegEncContext *s,
524 DCTELEM *block, int n, int qscale)
526 POWERPC_PERF_DECLARE(altivec_dct_unquantize_h263_num, 1);
527 int i, level, qmul, qadd;
530 assert(s->block_last_index[n]>=0);
532 POWERPC_PERF_START_COUNT(altivec_dct_unquantize_h263_num, 1);
534 qadd = (qscale - 1) | 1;
540 block[0] = block[0] * s->y_dc_scale;
542 block[0] = block[0] * s->c_dc_scale;
546 nCoeffs= 63; //does not allways use zigzag table
549 nCoeffs= s->intra_scantable.raster_end[ s->block_last_index[n] ];
552 #ifdef ALTIVEC_USE_REFERENCE_C_CODE
553 for(;i<=nCoeffs;i++) {
557 level = level * qmul - qadd;
559 level = level * qmul + qadd;
564 #else /* ALTIVEC_USE_REFERENCE_C_CODE */
566 register const_vector signed short vczero = (const_vector signed short)vec_splat_s16(0);
567 short __attribute__ ((aligned(16))) qmul8[] =
569 qmul, qmul, qmul, qmul,
570 qmul, qmul, qmul, qmul
572 short __attribute__ ((aligned(16))) qadd8[] =
574 qadd, qadd, qadd, qadd,
575 qadd, qadd, qadd, qadd
577 short __attribute__ ((aligned(16))) nqadd8[] =
579 -qadd, -qadd, -qadd, -qadd,
580 -qadd, -qadd, -qadd, -qadd
582 register vector signed short blockv, qmulv, qaddv, nqaddv, temp1;
583 register vector bool short blockv_null, blockv_neg;
584 register short backup_0 = block[0];
587 qmulv = vec_ld(0, qmul8);
588 qaddv = vec_ld(0, qadd8);
589 nqaddv = vec_ld(0, nqadd8);
591 #if 0 // block *is* 16 bytes-aligned, it seems.
592 // first make sure block[j] is 16 bytes-aligned
593 for(j = 0; (j <= nCoeffs) && ((((unsigned long)block) + (j << 1)) & 0x0000000F) ; j++) {
597 level = level * qmul - qadd;
599 level = level * qmul + qadd;
606 // vectorize all the 16 bytes-aligned blocks
608 for(; (j + 7) <= nCoeffs ; j+=8)
610 blockv = vec_ld(j << 1, block);
611 blockv_neg = vec_cmplt(blockv, vczero);
612 blockv_null = vec_cmpeq(blockv, vczero);
613 // choose between +qadd or -qadd as the third operand
614 temp1 = vec_sel(qaddv, nqaddv, blockv_neg);
615 // multiply & add (block{i,i+7} * qmul [+-] qadd)
616 temp1 = vec_mladd(blockv, qmulv, temp1);
617 // put 0 where block[{i,i+7} used to have 0
618 blockv = vec_sel(temp1, blockv, blockv_null);
619 vec_st(blockv, j << 1, block);
622 // if nCoeffs isn't a multiple of 8, finish the job
623 // using good old scalar units.
624 // (we could do it using a truncated vector,
625 // but I'm not sure it's worth the hassle)
626 for(; j <= nCoeffs ; j++) {
630 level = level * qmul - qadd;
632 level = level * qmul + qadd;
639 { // cheat. this avoid special-casing the first iteration
643 #endif /* ALTIVEC_USE_REFERENCE_C_CODE */
645 POWERPC_PERF_STOP_COUNT(altivec_dct_unquantize_h263_num, nCoeffs == 63);