/src/FreeImage/Source/LibJPEG/jidctint.c
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1/* 2 * jidctint.c 3 * 4 * Copyright (C) 1991-1998, Thomas G. Lane. 5 * Modification developed 2002-2009 by Guido Vollbeding. 6 * This file is part of the Independent JPEG Group's software. 7 * For conditions of distribution and use, see the accompanying README file. 8 * 9 * This file contains a slow-but-accurate integer implementation of the 10 * inverse DCT (Discrete Cosine Transform). In the IJG code, this routine 11 * must also perform dequantization of the input coefficients. 12 * 13 * A 2-D IDCT can be done by 1-D IDCT on each column followed by 1-D IDCT 14 * on each row (or vice versa, but it's more convenient to emit a row at 15 * a time). Direct algorithms are also available, but they are much more 16 * complex and seem not to be any faster when reduced to code. 17 * 18 * This implementation is based on an algorithm described in 19 * C. Loeffler, A. Ligtenberg and G. Moschytz, "Practical Fast 1-D DCT 20 * Algorithms with 11 Multiplications", Proc. Int'l. Conf. on Acoustics, 21 * Speech, and Signal Processing 1989 (ICASSP '89), pp. 988-991. 22 * The primary algorithm described there uses 11 multiplies and 29 adds. 23 * We use their alternate method with 12 multiplies and 32 adds. 24 * The advantage of this method is that no data path contains more than one 25 * multiplication; this allows a very simple and accurate implementation in 26 * scaled fixed-point arithmetic, with a minimal number of shifts. 27 * 28 * We also provide IDCT routines with various output sample block sizes for 29 * direct resolution reduction or enlargement and for direct resolving the 30 * common 2x1 and 1x2 subsampling cases without additional resampling: NxN 31 * (N=1...16), 2NxN, and Nx2N (N=1...8) pixels for one 8x8 input DCT block. 32 * 33 * For N<8 we simply take the corresponding low-frequency coefficients of 34 * the 8x8 input DCT block and apply an NxN point IDCT on the sub-block 35 * to yield the downscaled outputs. 36 * This can be seen as direct low-pass downsampling from the DCT domain 37 * point of view rather than the usual spatial domain point of view, 38 * yielding significant computational savings and results at least 39 * as good as common bilinear (averaging) spatial downsampling. 40 * 41 * For N>8 we apply a partial NxN IDCT on the 8 input coefficients as 42 * lower frequencies and higher frequencies assumed to be zero. 43 * It turns out that the computational effort is similar to the 8x8 IDCT 44 * regarding the output size. 45 * Furthermore, the scaling and descaling is the same for all IDCT sizes. 46 * 47 * CAUTION: We rely on the FIX() macro except for the N=1,2,4,8 cases 48 * since there would be too many additional constants to pre-calculate. 49 */ 50 51#define JPEG_INTERNALS 52#include "jinclude.h" 53#include "jpeglib.h" 54#include "jdct.h" /* Private declarations for DCT subsystem */ 55 56#ifdef DCT_ISLOW_SUPPORTED 57 58 59/* 60 * This module is specialized to the case DCTSIZE = 8. 61 */ 62 63#if DCTSIZE != 8 64 Sorry, this code only copes with 8x8 DCT blocks. /* deliberate syntax err */ 65#endif 66 67 68/* 69 * The poop on this scaling stuff is as follows: 70 * 71 * Each 1-D IDCT step produces outputs which are a factor of sqrt(N) 72 * larger than the true IDCT outputs. The final outputs are therefore 73 * a factor of N larger than desired; since N=8 this can be cured by 74 * a simple right shift at the end of the algorithm. The advantage of 75 * this arrangement is that we save two multiplications per 1-D IDCT, 76 * because the y0 and y4 inputs need not be divided by sqrt(N). 77 * 78 * We have to do addition and subtraction of the integer inputs, which 79 * is no problem, and multiplication by fractional constants, which is 80 * a problem to do in integer arithmetic. We multiply all the constants 81 * by CONST_SCALE and convert them to integer constants (thus retaining 82 * CONST_BITS bits of precision in the constants). After doing a 83 * multiplication we have to divide the product by CONST_SCALE, with proper 84 * rounding, to produce the correct output. This division can be done 85 * cheaply as a right shift of CONST_BITS bits. We postpone shifting 86 * as long as possible so that partial sums can be added together with 87 * full fractional precision. 88 * 89 * The outputs of the first pass are scaled up by PASS1_BITS bits so that 90 * they are represented to better-than-integral precision. These outputs 91 * require BITS_IN_JSAMPLE + PASS1_BITS + 3 bits; this fits in a 16-bit word 92 * with the recommended scaling. (To scale up 12-bit sample data further, an 93 * intermediate INT32 array would be needed.) 94 * 95 * To avoid overflow of the 32-bit intermediate results in pass 2, we must 96 * have BITS_IN_JSAMPLE + CONST_BITS + PASS1_BITS <= 26. Error analysis 97 * shows that the values given below are the most effective. 98 */ 99 100#if BITS_IN_JSAMPLE == 8 101#define CONST_BITS 13 102#define PASS1_BITS 2 103#else 104#define CONST_BITS 13 105#define PASS1_BITS 1 /* lose a little precision to avoid overflow */ 106#endif 107 108/* Some C compilers fail to reduce "FIX(constant)" at compile time, thus 109 * causing a lot of useless floating-point operations at run time. 110 * To get around this we use the following pre-calculated constants. 111 * If you change CONST_BITS you may want to add appropriate values. 112 * (With a reasonable C compiler, you can just rely on the FIX() macro...) 113 */ 114 115#if CONST_BITS == 13 116#define FIX_0_298631336 ((INT32) 2446) /* FIX(0.298631336) */ 117#define FIX_0_390180644 ((INT32) 3196) /* FIX(0.390180644) */ 118#define FIX_0_541196100 ((INT32) 4433) /* FIX(0.541196100) */ 119#define FIX_0_765366865 ((INT32) 6270) /* FIX(0.765366865) */ 120#define FIX_0_899976223 ((INT32) 7373) /* FIX(0.899976223) */ 121#define FIX_1_175875602 ((INT32) 9633) /* FIX(1.175875602) */ 122#define FIX_1_501321110 ((INT32) 12299) /* FIX(1.501321110) */ 123#define FIX_1_847759065 ((INT32) 15137) /* FIX(1.847759065) */ 124#define FIX_1_961570560 ((INT32) 16069) /* FIX(1.961570560) */ 125#define FIX_2_053119869 ((INT32) 16819) /* FIX(2.053119869) */ 126#define FIX_2_562915447 ((INT32) 20995) /* FIX(2.562915447) */ 127#define FIX_3_072711026 ((INT32) 25172) /* FIX(3.072711026) */ 128#else 129#define FIX_0_298631336 FIX(0.298631336) 130#define FIX_0_390180644 FIX(0.390180644) 131#define FIX_0_541196100 FIX(0.541196100) 132#define FIX_0_765366865 FIX(0.765366865) 133#define FIX_0_899976223 FIX(0.899976223) 134#define FIX_1_175875602 FIX(1.175875602) 135#define FIX_1_501321110 FIX(1.501321110) 136#define FIX_1_847759065 FIX(1.847759065) 137#define FIX_1_961570560 FIX(1.961570560) 138#define FIX_2_053119869 FIX(2.053119869) 139#define FIX_2_562915447 FIX(2.562915447) 140#define FIX_3_072711026 FIX(3.072711026) 141#endif 142 143 144/* Multiply an INT32 variable by an INT32 constant to yield an INT32 result. 145 * For 8-bit samples with the recommended scaling, all the variable 146 * and constant values involved are no more than 16 bits wide, so a 147 * 16x16->32 bit multiply can be used instead of a full 32x32 multiply. 148 * For 12-bit samples, a full 32-bit multiplication will be needed. 149 */ 150 151#if BITS_IN_JSAMPLE == 8 152#define MULTIPLY(var,const) MULTIPLY16C16(var,const) 153#else 154#define MULTIPLY(var,const) ((var) * (const)) 155#endif 156 157 158/* Dequantize a coefficient by multiplying it by the multiplier-table 159 * entry; produce an int result. In this module, both inputs and result 160 * are 16 bits or less, so either int or short multiply will work. 161 */ 162 163#define DEQUANTIZE(coef,quantval) (((ISLOW_MULT_TYPE) (coef)) * (quantval)) 164 165 166/* 167 * Perform dequantization and inverse DCT on one block of coefficients. 168 */ 169 170GLOBAL(void) 171jpeg_idct_islow (j_decompress_ptr cinfo, jpeg_component_info * compptr, 172 JCOEFPTR coef_block, 173 JSAMPARRAY output_buf, JDIMENSION output_col) 174{ 175 INT32 tmp0, tmp1, tmp2, tmp3; 176 INT32 tmp10, tmp11, tmp12, tmp13; 177 INT32 z1, z2, z3; 178 JCOEFPTR inptr; 179 ISLOW_MULT_TYPE * quantptr; 180 int * wsptr; 181 JSAMPROW outptr; 182 JSAMPLE *range_limit = IDCT_range_limit(cinfo); 183 int ctr; 184 int workspace[DCTSIZE2]; /* buffers data between passes */ 185 SHIFT_TEMPS 186 187 /* Pass 1: process columns from input, store into work array. */ 188 /* Note results are scaled up by sqrt(8) compared to a true IDCT; */ 189 /* furthermore, we scale the results by 2**PASS1_BITS. */ 190 191 inptr = coef_block; 192 quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table; 193 wsptr = workspace; 194 for (ctr = DCTSIZE; ctr > 0; ctr--) { 195 /* Due to quantization, we will usually find that many of the input 196 * coefficients are zero, especially the AC terms. We can exploit this 197 * by short-circuiting the IDCT calculation for any column in which all 198 * the AC terms are zero. In that case each output is equal to the 199 * DC coefficient (with scale factor as needed). 200 * With typical images and quantization tables, half or more of the 201 * column DCT calculations can be simplified this way. 202 */ 203 204 if (inptr[DCTSIZE*1] == 0 && inptr[DCTSIZE*2] == 0 && 205 inptr[DCTSIZE*3] == 0 && inptr[DCTSIZE*4] == 0 && 206 inptr[DCTSIZE*5] == 0 && inptr[DCTSIZE*6] == 0 && 207 inptr[DCTSIZE*7] == 0) { 208 /* AC terms all zero */ 209 int dcval = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]) << PASS1_BITS; 210 211 wsptr[DCTSIZE*0] = dcval; 212 wsptr[DCTSIZE*1] = dcval; 213 wsptr[DCTSIZE*2] = dcval; 214 wsptr[DCTSIZE*3] = dcval; 215 wsptr[DCTSIZE*4] = dcval; 216 wsptr[DCTSIZE*5] = dcval; 217 wsptr[DCTSIZE*6] = dcval; 218 wsptr[DCTSIZE*7] = dcval; 219 220 inptr++; /* advance pointers to next column */ 221 quantptr++; 222 wsptr++; 223 continue; 224 } 225 226 /* Even part: reverse the even part of the forward DCT. */ 227 /* The rotator is sqrt(2)*c(-6). */ 228 229 z2 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]); 230 z3 = DEQUANTIZE(inptr[DCTSIZE*6], quantptr[DCTSIZE*6]); 231 232 z1 = MULTIPLY(z2 + z3, FIX_0_541196100); 233 tmp2 = z1 + MULTIPLY(z2, FIX_0_765366865); 234 tmp3 = z1 - MULTIPLY(z3, FIX_1_847759065); 235 236 z2 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]); 237 z3 = DEQUANTIZE(inptr[DCTSIZE*4], quantptr[DCTSIZE*4]); 238 z2 <<= CONST_BITS; 239 z3 <<= CONST_BITS; 240 /* Add fudge factor here for final descale. */ 241 z2 += ONE << (CONST_BITS-PASS1_BITS-1); 242 243 tmp0 = z2 + z3; 244 tmp1 = z2 - z3; 245 246 tmp10 = tmp0 + tmp2; 247 tmp13 = tmp0 - tmp2; 248 tmp11 = tmp1 + tmp3; 249 tmp12 = tmp1 - tmp3; 250 251 /* Odd part per figure 8; the matrix is unitary and hence its 252 * transpose is its inverse. i0..i3 are y7,y5,y3,y1 respectively. 253 */ 254 255 tmp0 = DEQUANTIZE(inptr[DCTSIZE*7], quantptr[DCTSIZE*7]); 256 tmp1 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5]); 257 tmp2 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]); 258 tmp3 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]); 259 260 z2 = tmp0 + tmp2; 261 z3 = tmp1 + tmp3; 262 263 z1 = MULTIPLY(z2 + z3, FIX_1_175875602); /* sqrt(2) * c3 */ 264 z2 = MULTIPLY(z2, - FIX_1_961570560); /* sqrt(2) * (-c3-c5) */ 265 z3 = MULTIPLY(z3, - FIX_0_390180644); /* sqrt(2) * (c5-c3) */ 266 z2 += z1; 267 z3 += z1; 268 269 z1 = MULTIPLY(tmp0 + tmp3, - FIX_0_899976223); /* sqrt(2) * (c7-c3) */ 270 tmp0 = MULTIPLY(tmp0, FIX_0_298631336); /* sqrt(2) * (-c1+c3+c5-c7) */ 271 tmp3 = MULTIPLY(tmp3, FIX_1_501321110); /* sqrt(2) * ( c1+c3-c5-c7) */ 272 tmp0 += z1 + z2; 273 tmp3 += z1 + z3; 274 275 z1 = MULTIPLY(tmp1 + tmp2, - FIX_2_562915447); /* sqrt(2) * (-c1-c3) */ 276 tmp1 = MULTIPLY(tmp1, FIX_2_053119869); /* sqrt(2) * ( c1+c3-c5+c7) */ 277 tmp2 = MULTIPLY(tmp2, FIX_3_072711026); /* sqrt(2) * ( c1+c3+c5-c7) */ 278 tmp1 += z1 + z3; 279 tmp2 += z1 + z2; 280 281 /* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */ 282 283 wsptr[DCTSIZE*0] = (int) RIGHT_SHIFT(tmp10 + tmp3, CONST_BITS-PASS1_BITS); 284 wsptr[DCTSIZE*7] = (int) RIGHT_SHIFT(tmp10 - tmp3, CONST_BITS-PASS1_BITS); 285 wsptr[DCTSIZE*1] = (int) RIGHT_SHIFT(tmp11 + tmp2, CONST_BITS-PASS1_BITS); 286 wsptr[DCTSIZE*6] = (int) RIGHT_SHIFT(tmp11 - tmp2, CONST_BITS-PASS1_BITS); 287 wsptr[DCTSIZE*2] = (int) RIGHT_SHIFT(tmp12 + tmp1, CONST_BITS-PASS1_BITS); 288 wsptr[DCTSIZE*5] = (int) RIGHT_SHIFT(tmp12 - tmp1, CONST_BITS-PASS1_BITS); 289 wsptr[DCTSIZE*3] = (int) RIGHT_SHIFT(tmp13 + tmp0, CONST_BITS-PASS1_BITS); 290 wsptr[DCTSIZE*4] = (int) RIGHT_SHIFT(tmp13 - tmp0, CONST_BITS-PASS1_BITS); 291 292 inptr++; /* advance pointers to next column */ 293 quantptr++; 294 wsptr++; 295 } 296 297 /* Pass 2: process rows from work array, store into output array. */ 298 /* Note that we must descale the results by a factor of 8 == 2**3, */ 299 /* and also undo the PASS1_BITS scaling. */ 300 301 wsptr = workspace; 302 for (ctr = 0; ctr < DCTSIZE; ctr++) { 303 outptr = output_buf[ctr] + output_col; 304 /* Rows of zeroes can be exploited in the same way as we did with columns. 305 * However, the column calculation has created many nonzero AC terms, so 306 * the simplification applies less often (typically 5% to 10% of the time). 307 * On machines with very fast multiplication, it's possible that the 308 * test takes more time than it's worth. In that case this section 309 * may be commented out. 310 */ 311 312#ifndef NO_ZERO_ROW_TEST 313 if (wsptr[1] == 0 && wsptr[2] == 0 && wsptr[3] == 0 && wsptr[4] == 0 && 314 wsptr[5] == 0 && wsptr[6] == 0 && wsptr[7] == 0) { 315 /* AC terms all zero */ 316 JSAMPLE dcval = range_limit[(int) DESCALE((INT32) wsptr[0], PASS1_BITS+3) 317 & RANGE_MASK]; 318 319 outptr[0] = dcval; 320 outptr[1] = dcval; 321 outptr[2] = dcval; 322 outptr[3] = dcval; 323 outptr[4] = dcval; 324 outptr[5] = dcval; 325 outptr[6] = dcval; 326 outptr[7] = dcval; 327 328 wsptr += DCTSIZE; /* advance pointer to next row */ 329 continue; 330 } 331#endif 332 333 /* Even part: reverse the even part of the forward DCT. */ 334 /* The rotator is sqrt(2)*c(-6). */ 335 336 z2 = (INT32) wsptr[2]; 337 z3 = (INT32) wsptr[6]; 338 339 z1 = MULTIPLY(z2 + z3, FIX_0_541196100); 340 tmp2 = z1 + MULTIPLY(z2, FIX_0_765366865); 341 tmp3 = z1 - MULTIPLY(z3, FIX_1_847759065); 342 343 /* Add fudge factor here for final descale. */ 344 z2 = (INT32) wsptr[0] + (ONE << (PASS1_BITS+2)); 345 z3 = (INT32) wsptr[4]; 346 347 tmp0 = (z2 + z3) << CONST_BITS; 348 tmp1 = (z2 - z3) << CONST_BITS; 349 350 tmp10 = tmp0 + tmp2; 351 tmp13 = tmp0 - tmp2; 352 tmp11 = tmp1 + tmp3; 353 tmp12 = tmp1 - tmp3; 354 355 /* Odd part per figure 8; the matrix is unitary and hence its 356 * transpose is its inverse. i0..i3 are y7,y5,y3,y1 respectively. 357 */ 358 359 tmp0 = (INT32) wsptr[7]; 360 tmp1 = (INT32) wsptr[5]; 361 tmp2 = (INT32) wsptr[3]; 362 tmp3 = (INT32) wsptr[1]; 363 364 z2 = tmp0 + tmp2; 365 z3 = tmp1 + tmp3; 366 367 z1 = MULTIPLY(z2 + z3, FIX_1_175875602); /* sqrt(2) * c3 */ 368 z2 = MULTIPLY(z2, - FIX_1_961570560); /* sqrt(2) * (-c3-c5) */ 369 z3 = MULTIPLY(z3, - FIX_0_390180644); /* sqrt(2) * (c5-c3) */ 370 z2 += z1; 371 z3 += z1; 372 373 z1 = MULTIPLY(tmp0 + tmp3, - FIX_0_899976223); /* sqrt(2) * (c7-c3) */ 374 tmp0 = MULTIPLY(tmp0, FIX_0_298631336); /* sqrt(2) * (-c1+c3+c5-c7) */ 375 tmp3 = MULTIPLY(tmp3, FIX_1_501321110); /* sqrt(2) * ( c1+c3-c5-c7) */ 376 tmp0 += z1 + z2; 377 tmp3 += z1 + z3; 378 379 z1 = MULTIPLY(tmp1 + tmp2, - FIX_2_562915447); /* sqrt(2) * (-c1-c3) */ 380 tmp1 = MULTIPLY(tmp1, FIX_2_053119869); /* sqrt(2) * ( c1+c3-c5+c7) */ 381 tmp2 = MULTIPLY(tmp2, FIX_3_072711026); /* sqrt(2) * ( c1+c3+c5-c7) */ 382 tmp1 += z1 + z3; 383 tmp2 += z1 + z2; 384 385 /* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */ 386 387 outptr[0] = range_limit[(int) RIGHT_SHIFT(tmp10 + tmp3, 388 CONST_BITS+PASS1_BITS+3) 389 & RANGE_MASK]; 390 outptr[7] = range_limit[(int) RIGHT_SHIFT(tmp10 - tmp3, 391 CONST_BITS+PASS1_BITS+3) 392 & RANGE_MASK]; 393 outptr[1] = range_limit[(int) RIGHT_SHIFT(tmp11 + tmp2, 394 CONST_BITS+PASS1_BITS+3) 395 & RANGE_MASK]; 396 outptr[6] = range_limit[(int) RIGHT_SHIFT(tmp11 - tmp2, 397 CONST_BITS+PASS1_BITS+3) 398 & RANGE_MASK]; 399 outptr[2] = range_limit[(int) RIGHT_SHIFT(tmp12 + tmp1, 400 CONST_BITS+PASS1_BITS+3) 401 & RANGE_MASK]; 402 outptr[5] = range_limit[(int) RIGHT_SHIFT(tmp12 - tmp1, 403 CONST_BITS+PASS1_BITS+3) 404 & RANGE_MASK]; 405 outptr[3] = range_limit[(int) RIGHT_SHIFT(tmp13 + tmp0, 406 CONST_BITS+PASS1_BITS+3) 407 & RANGE_MASK]; 408 outptr[4] = range_limit[(int) RIGHT_SHIFT(tmp13 - tmp0, 409 CONST_BITS+PASS1_BITS+3) 410 & RANGE_MASK]; 411 412 wsptr += DCTSIZE; /* advance pointer to next row */ 413 } 414} 415 416#ifdef IDCT_SCALING_SUPPORTED 417 418 419/* 420 * Perform dequantization and inverse DCT on one block of coefficients, 421 * producing a 7x7 output block. 422 * 423 * Optimized algorithm with 12 multiplications in the 1-D kernel. 424 * cK represents sqrt(2) * cos(K*pi/14). 425 */ 426 427GLOBAL(void) 428jpeg_idct_7x7 (j_decompress_ptr cinfo, jpeg_component_info * compptr, 429 JCOEFPTR coef_block, 430 JSAMPARRAY output_buf, JDIMENSION output_col) 431{ 432 INT32 tmp0, tmp1, tmp2, tmp10, tmp11, tmp12, tmp13; 433 INT32 z1, z2, z3; 434 JCOEFPTR inptr; 435 ISLOW_MULT_TYPE * quantptr; 436 int * wsptr; 437 JSAMPROW outptr; 438 JSAMPLE *range_limit = IDCT_range_limit(cinfo); 439 int ctr; 440 int workspace[7*7]; /* buffers data between passes */ 441 SHIFT_TEMPS 442 443 /* Pass 1: process columns from input, store into work array. */ 444 445 inptr = coef_block; 446 quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table; 447 wsptr = workspace; 448 for (ctr = 0; ctr < 7; ctr++, inptr++, quantptr++, wsptr++) { 449 /* Even part */ 450 451 tmp13 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]); 452 tmp13 <<= CONST_BITS; 453 /* Add fudge factor here for final descale. */ 454 tmp13 += ONE << (CONST_BITS-PASS1_BITS-1); 455 456 z1 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]); 457 z2 = DEQUANTIZE(inptr[DCTSIZE*4], quantptr[DCTSIZE*4]); 458 z3 = DEQUANTIZE(inptr[DCTSIZE*6], quantptr[DCTSIZE*6]); 459 460 tmp10 = MULTIPLY(z2 - z3, FIX(0.881747734)); /* c4 */ 461 tmp12 = MULTIPLY(z1 - z2, FIX(0.314692123)); /* c6 */ 462 tmp11 = tmp10 + tmp12 + tmp13 - MULTIPLY(z2, FIX(1.841218003)); /* c2+c4-c6 */ 463 tmp0 = z1 + z3; 464 z2 -= tmp0; 465 tmp0 = MULTIPLY(tmp0, FIX(1.274162392)) + tmp13; /* c2 */ 466 tmp10 += tmp0 - MULTIPLY(z3, FIX(0.077722536)); /* c2-c4-c6 */ 467 tmp12 += tmp0 - MULTIPLY(z1, FIX(2.470602249)); /* c2+c4+c6 */ 468 tmp13 += MULTIPLY(z2, FIX(1.414213562)); /* c0 */ 469 470 /* Odd part */ 471 472 z1 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]); 473 z2 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]); 474 z3 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5]); 475 476 tmp1 = MULTIPLY(z1 + z2, FIX(0.935414347)); /* (c3+c1-c5)/2 */ 477 tmp2 = MULTIPLY(z1 - z2, FIX(0.170262339)); /* (c3+c5-c1)/2 */ 478 tmp0 = tmp1 - tmp2; 479 tmp1 += tmp2; 480 tmp2 = MULTIPLY(z2 + z3, - FIX(1.378756276)); /* -c1 */ 481 tmp1 += tmp2; 482 z2 = MULTIPLY(z1 + z3, FIX(0.613604268)); /* c5 */ 483 tmp0 += z2; 484 tmp2 += z2 + MULTIPLY(z3, FIX(1.870828693)); /* c3+c1-c5 */ 485 486 /* Final output stage */ 487 488 wsptr[7*0] = (int) RIGHT_SHIFT(tmp10 + tmp0, CONST_BITS-PASS1_BITS); 489 wsptr[7*6] = (int) RIGHT_SHIFT(tmp10 - tmp0, CONST_BITS-PASS1_BITS); 490 wsptr[7*1] = (int) RIGHT_SHIFT(tmp11 + tmp1, CONST_BITS-PASS1_BITS); 491 wsptr[7*5] = (int) RIGHT_SHIFT(tmp11 - tmp1, CONST_BITS-PASS1_BITS); 492 wsptr[7*2] = (int) RIGHT_SHIFT(tmp12 + tmp2, CONST_BITS-PASS1_BITS); 493 wsptr[7*4] = (int) RIGHT_SHIFT(tmp12 - tmp2, CONST_BITS-PASS1_BITS); 494 wsptr[7*3] = (int) RIGHT_SHIFT(tmp13, CONST_BITS-PASS1_BITS); 495 } 496 497 /* Pass 2: process 7 rows from work array, store into output array. */ 498 499 wsptr = workspace; 500 for (ctr = 0; ctr < 7; ctr++) { 501 outptr = output_buf[ctr] + output_col; 502 503 /* Even part */ 504 505 /* Add fudge factor here for final descale. */ 506 tmp13 = (INT32) wsptr[0] + (ONE << (PASS1_BITS+2)); 507 tmp13 <<= CONST_BITS; 508 509 z1 = (INT32) wsptr[2]; 510 z2 = (INT32) wsptr[4]; 511 z3 = (INT32) wsptr[6]; 512 513 tmp10 = MULTIPLY(z2 - z3, FIX(0.881747734)); /* c4 */ 514 tmp12 = MULTIPLY(z1 - z2, FIX(0.314692123)); /* c6 */ 515 tmp11 = tmp10 + tmp12 + tmp13 - MULTIPLY(z2, FIX(1.841218003)); /* c2+c4-c6 */ 516 tmp0 = z1 + z3; 517 z2 -= tmp0; 518 tmp0 = MULTIPLY(tmp0, FIX(1.274162392)) + tmp13; /* c2 */ 519 tmp10 += tmp0 - MULTIPLY(z3, FIX(0.077722536)); /* c2-c4-c6 */ 520 tmp12 += tmp0 - MULTIPLY(z1, FIX(2.470602249)); /* c2+c4+c6 */ 521 tmp13 += MULTIPLY(z2, FIX(1.414213562)); /* c0 */ 522 523 /* Odd part */ 524 525 z1 = (INT32) wsptr[1]; 526 z2 = (INT32) wsptr[3]; 527 z3 = (INT32) wsptr[5]; 528 529 tmp1 = MULTIPLY(z1 + z2, FIX(0.935414347)); /* (c3+c1-c5)/2 */ 530 tmp2 = MULTIPLY(z1 - z2, FIX(0.170262339)); /* (c3+c5-c1)/2 */ 531 tmp0 = tmp1 - tmp2; 532 tmp1 += tmp2; 533 tmp2 = MULTIPLY(z2 + z3, - FIX(1.378756276)); /* -c1 */ 534 tmp1 += tmp2; 535 z2 = MULTIPLY(z1 + z3, FIX(0.613604268)); /* c5 */ 536 tmp0 += z2; 537 tmp2 += z2 + MULTIPLY(z3, FIX(1.870828693)); /* c3+c1-c5 */ 538 539 /* Final output stage */ 540 541 outptr[0] = range_limit[(int) RIGHT_SHIFT(tmp10 + tmp0, 542 CONST_BITS+PASS1_BITS+3) 543 & RANGE_MASK]; 544 outptr[6] = range_limit[(int) RIGHT_SHIFT(tmp10 - tmp0, 545 CONST_BITS+PASS1_BITS+3) 546 & RANGE_MASK]; 547 outptr[1] = range_limit[(int) RIGHT_SHIFT(tmp11 + tmp1, 548 CONST_BITS+PASS1_BITS+3) 549 & RANGE_MASK]; 550 outptr[5] = range_limit[(int) RIGHT_SHIFT(tmp11 - tmp1, 551 CONST_BITS+PASS1_BITS+3) 552 & RANGE_MASK]; 553 outptr[2] = range_limit[(int) RIGHT_SHIFT(tmp12 + tmp2, 554 CONST_BITS+PASS1_BITS+3) 555 & RANGE_MASK]; 556 outptr[4] = range_limit[(int) RIGHT_SHIFT(tmp12 - tmp2, 557 CONST_BITS+PASS1_BITS+3) 558 & RANGE_MASK]; 559 outptr[3] = range_limit[(int) RIGHT_SHIFT(tmp13, 560 CONST_BITS+PASS1_BITS+3) 561 & RANGE_MASK]; 562 563 wsptr += 7; /* advance pointer to next row */ 564 } 565} 566 567 568/* 569 * Perform dequantization and inverse DCT on one block of coefficients, 570 * producing a reduced-size 6x6 output block. 571 * 572 * Optimized algorithm with 3 multiplications in the 1-D kernel. 573 * cK represents sqrt(2) * cos(K*pi/12). 574 */ 575 576GLOBAL(void) 577jpeg_idct_6x6 (j_decompress_ptr cinfo, jpeg_component_info * compptr, 578 JCOEFPTR coef_block, 579 JSAMPARRAY output_buf, JDIMENSION output_col) 580{ 581 INT32 tmp0, tmp1, tmp2, tmp10, tmp11, tmp12; 582 INT32 z1, z2, z3; 583 JCOEFPTR inptr; 584 ISLOW_MULT_TYPE * quantptr; 585 int * wsptr; 586 JSAMPROW outptr; 587 JSAMPLE *range_limit = IDCT_range_limit(cinfo); 588 int ctr; 589 int workspace[6*6]; /* buffers data between passes */ 590 SHIFT_TEMPS 591 592 /* Pass 1: process columns from input, store into work array. */ 593 594 inptr = coef_block; 595 quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table; 596 wsptr = workspace; 597 for (ctr = 0; ctr < 6; ctr++, inptr++, quantptr++, wsptr++) { 598 /* Even part */ 599 600 tmp0 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]); 601 tmp0 <<= CONST_BITS; 602 /* Add fudge factor here for final descale. */ 603 tmp0 += ONE << (CONST_BITS-PASS1_BITS-1); 604 tmp2 = DEQUANTIZE(inptr[DCTSIZE*4], quantptr[DCTSIZE*4]); 605 tmp10 = MULTIPLY(tmp2, FIX(0.707106781)); /* c4 */ 606 tmp1 = tmp0 + tmp10; 607 tmp11 = RIGHT_SHIFT(tmp0 - tmp10 - tmp10, CONST_BITS-PASS1_BITS); 608 tmp10 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]); 609 tmp0 = MULTIPLY(tmp10, FIX(1.224744871)); /* c2 */ 610 tmp10 = tmp1 + tmp0; 611 tmp12 = tmp1 - tmp0; 612 613 /* Odd part */ 614 615 z1 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]); 616 z2 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]); 617 z3 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5]); 618 tmp1 = MULTIPLY(z1 + z3, FIX(0.366025404)); /* c5 */ 619 tmp0 = tmp1 + ((z1 + z2) << CONST_BITS); 620 tmp2 = tmp1 + ((z3 - z2) << CONST_BITS); 621 tmp1 = (z1 - z2 - z3) << PASS1_BITS; 622 623 /* Final output stage */ 624 625 wsptr[6*0] = (int) RIGHT_SHIFT(tmp10 + tmp0, CONST_BITS-PASS1_BITS); 626 wsptr[6*5] = (int) RIGHT_SHIFT(tmp10 - tmp0, CONST_BITS-PASS1_BITS); 627 wsptr[6*1] = (int) (tmp11 + tmp1); 628 wsptr[6*4] = (int) (tmp11 - tmp1); 629 wsptr[6*2] = (int) RIGHT_SHIFT(tmp12 + tmp2, CONST_BITS-PASS1_BITS); 630 wsptr[6*3] = (int) RIGHT_SHIFT(tmp12 - tmp2, CONST_BITS-PASS1_BITS); 631 } 632 633 /* Pass 2: process 6 rows from work array, store into output array. */ 634 635 wsptr = workspace; 636 for (ctr = 0; ctr < 6; ctr++) { 637 outptr = output_buf[ctr] + output_col; 638 639 /* Even part */ 640 641 /* Add fudge factor here for final descale. */ 642 tmp0 = (INT32) wsptr[0] + (ONE << (PASS1_BITS+2)); 643 tmp0 <<= CONST_BITS; 644 tmp2 = (INT32) wsptr[4]; 645 tmp10 = MULTIPLY(tmp2, FIX(0.707106781)); /* c4 */ 646 tmp1 = tmp0 + tmp10; 647 tmp11 = tmp0 - tmp10 - tmp10; 648 tmp10 = (INT32) wsptr[2]; 649 tmp0 = MULTIPLY(tmp10, FIX(1.224744871)); /* c2 */ 650 tmp10 = tmp1 + tmp0; 651 tmp12 = tmp1 - tmp0; 652 653 /* Odd part */ 654 655 z1 = (INT32) wsptr[1]; 656 z2 = (INT32) wsptr[3]; 657 z3 = (INT32) wsptr[5]; 658 tmp1 = MULTIPLY(z1 + z3, FIX(0.366025404)); /* c5 */ 659 tmp0 = tmp1 + ((z1 + z2) << CONST_BITS); 660 tmp2 = tmp1 + ((z3 - z2) << CONST_BITS); 661 tmp1 = (z1 - z2 - z3) << CONST_BITS; 662 663 /* Final output stage */ 664 665 outptr[0] = range_limit[(int) RIGHT_SHIFT(tmp10 + tmp0, 666 CONST_BITS+PASS1_BITS+3) 667 & RANGE_MASK]; 668 outptr[5] = range_limit[(int) RIGHT_SHIFT(tmp10 - tmp0, 669 CONST_BITS+PASS1_BITS+3) 670 & RANGE_MASK]; 671 outptr[1] = range_limit[(int) RIGHT_SHIFT(tmp11 + tmp1, 672 CONST_BITS+PASS1_BITS+3) 673 & RANGE_MASK]; 674 outptr[4] = range_limit[(int) RIGHT_SHIFT(tmp11 - tmp1, 675 CONST_BITS+PASS1_BITS+3) 676 & RANGE_MASK]; 677 outptr[2] = range_limit[(int) RIGHT_SHIFT(tmp12 + tmp2, 678 CONST_BITS+PASS1_BITS+3) 679 & RANGE_MASK]; 680 outptr[3] = range_limit[(int) RIGHT_SHIFT(tmp12 - tmp2, 681 CONST_BITS+PASS1_BITS+3) 682 & RANGE_MASK]; 683 684 wsptr += 6; /* advance pointer to next row */ 685 } 686} 687 688 689/* 690 * Perform dequantization and inverse DCT on one block of coefficients, 691 * producing a reduced-size 5x5 output block. 692 * 693 * Optimized algorithm with 5 multiplications in the 1-D kernel. 694 * cK represents sqrt(2) * cos(K*pi/10). 695 */ 696 697GLOBAL(void) 698jpeg_idct_5x5 (j_decompress_ptr cinfo, jpeg_component_info * compptr, 699 JCOEFPTR coef_block, 700 JSAMPARRAY output_buf, JDIMENSION output_col) 701{ 702 INT32 tmp0, tmp1, tmp10, tmp11, tmp12; 703 INT32 z1, z2, z3; 704 JCOEFPTR inptr; 705 ISLOW_MULT_TYPE * quantptr; 706 int * wsptr; 707 JSAMPROW outptr; 708 JSAMPLE *range_limit = IDCT_range_limit(cinfo); 709 int ctr; 710 int workspace[5*5]; /* buffers data between passes */ 711 SHIFT_TEMPS 712 713 /* Pass 1: process columns from input, store into work array. */ 714 715 inptr = coef_block; 716 quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table; 717 wsptr = workspace; 718 for (ctr = 0; ctr < 5; ctr++, inptr++, quantptr++, wsptr++) { 719 /* Even part */ 720 721 tmp12 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]); 722 tmp12 <<= CONST_BITS; 723 /* Add fudge factor here for final descale. */ 724 tmp12 += ONE << (CONST_BITS-PASS1_BITS-1); 725 tmp0 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]); 726 tmp1 = DEQUANTIZE(inptr[DCTSIZE*4], quantptr[DCTSIZE*4]); 727 z1 = MULTIPLY(tmp0 + tmp1, FIX(0.790569415)); /* (c2+c4)/2 */ 728 z2 = MULTIPLY(tmp0 - tmp1, FIX(0.353553391)); /* (c2-c4)/2 */ 729 z3 = tmp12 + z2; 730 tmp10 = z3 + z1; 731 tmp11 = z3 - z1; 732 tmp12 -= z2 << 2; 733 734 /* Odd part */ 735 736 z2 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]); 737 z3 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]); 738 739 z1 = MULTIPLY(z2 + z3, FIX(0.831253876)); /* c3 */ 740 tmp0 = z1 + MULTIPLY(z2, FIX(0.513743148)); /* c1-c3 */ 741 tmp1 = z1 - MULTIPLY(z3, FIX(2.176250899)); /* c1+c3 */ 742 743 /* Final output stage */ 744 745 wsptr[5*0] = (int) RIGHT_SHIFT(tmp10 + tmp0, CONST_BITS-PASS1_BITS); 746 wsptr[5*4] = (int) RIGHT_SHIFT(tmp10 - tmp0, CONST_BITS-PASS1_BITS); 747 wsptr[5*1] = (int) RIGHT_SHIFT(tmp11 + tmp1, CONST_BITS-PASS1_BITS); 748 wsptr[5*3] = (int) RIGHT_SHIFT(tmp11 - tmp1, CONST_BITS-PASS1_BITS); 749 wsptr[5*2] = (int) RIGHT_SHIFT(tmp12, CONST_BITS-PASS1_BITS); 750 } 751 752 /* Pass 2: process 5 rows from work array, store into output array. */ 753 754 wsptr = workspace; 755 for (ctr = 0; ctr < 5; ctr++) { 756 outptr = output_buf[ctr] + output_col; 757 758 /* Even part */ 759 760 /* Add fudge factor here for final descale. */ 761 tmp12 = (INT32) wsptr[0] + (ONE << (PASS1_BITS+2)); 762 tmp12 <<= CONST_BITS; 763 tmp0 = (INT32) wsptr[2]; 764 tmp1 = (INT32) wsptr[4]; 765 z1 = MULTIPLY(tmp0 + tmp1, FIX(0.790569415)); /* (c2+c4)/2 */ 766 z2 = MULTIPLY(tmp0 - tmp1, FIX(0.353553391)); /* (c2-c4)/2 */ 767 z3 = tmp12 + z2; 768 tmp10 = z3 + z1; 769 tmp11 = z3 - z1; 770 tmp12 -= z2 << 2; 771 772 /* Odd part */ 773 774 z2 = (INT32) wsptr[1]; 775 z3 = (INT32) wsptr[3]; 776 777 z1 = MULTIPLY(z2 + z3, FIX(0.831253876)); /* c3 */ 778 tmp0 = z1 + MULTIPLY(z2, FIX(0.513743148)); /* c1-c3 */ 779 tmp1 = z1 - MULTIPLY(z3, FIX(2.176250899)); /* c1+c3 */ 780 781 /* Final output stage */ 782 783 outptr[0] = range_limit[(int) RIGHT_SHIFT(tmp10 + tmp0, 784 CONST_BITS+PASS1_BITS+3) 785 & RANGE_MASK]; 786 outptr[4] = range_limit[(int) RIGHT_SHIFT(tmp10 - tmp0, 787 CONST_BITS+PASS1_BITS+3) 788 & RANGE_MASK]; 789 outptr[1] = range_limit[(int) RIGHT_SHIFT(tmp11 + tmp1, 790 CONST_BITS+PASS1_BITS+3) 791 & RANGE_MASK]; 792 outptr[3] = range_limit[(int) RIGHT_SHIFT(tmp11 - tmp1, 793 CONST_BITS+PASS1_BITS+3) 794 & RANGE_MASK]; 795 outptr[2] = range_limit[(int) RIGHT_SHIFT(tmp12, 796 CONST_BITS+PASS1_BITS+3) 797 & RANGE_MASK]; 798 799 wsptr += 5; /* advance pointer to next row */ 800 } 801} 802 803 804/* 805 * Perform dequantization and inverse DCT on one block of coefficients, 806 * producing a reduced-size 4x4 output block. 807 * 808 * Optimized algorithm with 3 multiplications in the 1-D kernel. 809 * cK represents sqrt(2) * cos(K*pi/16) [refers to 8-point IDCT]. 810 */ 811 812GLOBAL(void) 813jpeg_idct_4x4 (j_decompress_ptr cinfo, jpeg_component_info * compptr, 814 JCOEFPTR coef_block, 815 JSAMPARRAY output_buf, JDIMENSION output_col) 816{ 817 INT32 tmp0, tmp2, tmp10, tmp12; 818 INT32 z1, z2, z3; 819 JCOEFPTR inptr; 820 ISLOW_MULT_TYPE * quantptr; 821 int * wsptr; 822 JSAMPROW outptr; 823 JSAMPLE *range_limit = IDCT_range_limit(cinfo); 824 int ctr; 825 int workspace[4*4]; /* buffers data between passes */ 826 SHIFT_TEMPS 827 828 /* Pass 1: process columns from input, store into work array. */ 829 830 inptr = coef_block; 831 quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table; 832 wsptr = workspace; 833 for (ctr = 0; ctr < 4; ctr++, inptr++, quantptr++, wsptr++) { 834 /* Even part */ 835 836 tmp0 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]); 837 tmp2 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]); 838 839 tmp10 = (tmp0 + tmp2) << PASS1_BITS; 840 tmp12 = (tmp0 - tmp2) << PASS1_BITS; 841 842 /* Odd part */ 843 /* Same rotation as in the even part of the 8x8 LL&M IDCT */ 844 845 z2 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]); 846 z3 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]); 847 848 z1 = MULTIPLY(z2 + z3, FIX_0_541196100); /* c6 */ 849 /* Add fudge factor here for final descale. */ 850 z1 += ONE << (CONST_BITS-PASS1_BITS-1); 851 tmp0 = RIGHT_SHIFT(z1 + MULTIPLY(z2, FIX_0_765366865), /* c2-c6 */ 852 CONST_BITS-PASS1_BITS); 853 tmp2 = RIGHT_SHIFT(z1 - MULTIPLY(z3, FIX_1_847759065), /* c2+c6 */ 854 CONST_BITS-PASS1_BITS); 855 856 /* Final output stage */ 857 858 wsptr[4*0] = (int) (tmp10 + tmp0); 859 wsptr[4*3] = (int) (tmp10 - tmp0); 860 wsptr[4*1] = (int) (tmp12 + tmp2); 861 wsptr[4*2] = (int) (tmp12 - tmp2); 862 } 863 864 /* Pass 2: process 4 rows from work array, store into output array. */ 865 866 wsptr = workspace; 867 for (ctr = 0; ctr < 4; ctr++) { 868 outptr = output_buf[ctr] + output_col; 869 870 /* Even part */ 871 872 /* Add fudge factor here for final descale. */ 873 tmp0 = (INT32) wsptr[0] + (ONE << (PASS1_BITS+2)); 874 tmp2 = (INT32) wsptr[2]; 875 876 tmp10 = (tmp0 + tmp2) << CONST_BITS; 877 tmp12 = (tmp0 - tmp2) << CONST_BITS; 878 879 /* Odd part */ 880 /* Same rotation as in the even part of the 8x8 LL&M IDCT */ 881 882 z2 = (INT32) wsptr[1]; 883 z3 = (INT32) wsptr[3]; 884 885 z1 = MULTIPLY(z2 + z3, FIX_0_541196100); /* c6 */ 886 tmp0 = z1 + MULTIPLY(z2, FIX_0_765366865); /* c2-c6 */ 887 tmp2 = z1 - MULTIPLY(z3, FIX_1_847759065); /* c2+c6 */ 888 889 /* Final output stage */ 890 891 outptr[0] = range_limit[(int) RIGHT_SHIFT(tmp10 + tmp0, 892 CONST_BITS+PASS1_BITS+3) 893 & RANGE_MASK]; 894 outptr[3] = range_limit[(int) RIGHT_SHIFT(tmp10 - tmp0, 895 CONST_BITS+PASS1_BITS+3) 896 & RANGE_MASK]; 897 outptr[1] = range_limit[(int) RIGHT_SHIFT(tmp12 + tmp2, 898 CONST_BITS+PASS1_BITS+3) 899 & RANGE_MASK]; 900 outptr[2] = range_limit[(int) RIGHT_SHIFT(tmp12 - tmp2, 901 CONST_BITS+PASS1_BITS+3) 902 & RANGE_MASK]; 903 904 wsptr += 4; /* advance pointer to next row */ 905 } 906} 907 908 909/* 910 * Perform dequantization and inverse DCT on one block of coefficients, 911 * producing a reduced-size 3x3 output block. 912 * 913 * Optimized algorithm with 2 multiplications in the 1-D kernel. 914 * cK represents sqrt(2) * cos(K*pi/6). 915 */ 916 917GLOBAL(void) 918jpeg_idct_3x3 (j_decompress_ptr cinfo, jpeg_component_info * compptr, 919 JCOEFPTR coef_block, 920 JSAMPARRAY output_buf, JDIMENSION output_col) 921{ 922 INT32 tmp0, tmp2, tmp10, tmp12; 923 JCOEFPTR inptr; 924 ISLOW_MULT_TYPE * quantptr; 925 int * wsptr; 926 JSAMPROW outptr; 927 JSAMPLE *range_limit = IDCT_range_limit(cinfo); 928 int ctr; 929 int workspace[3*3]; /* buffers data between passes */ 930 SHIFT_TEMPS 931 932 /* Pass 1: process columns from input, store into work array. */ 933 934 inptr = coef_block; 935 quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table; 936 wsptr = workspace; 937 for (ctr = 0; ctr < 3; ctr++, inptr++, quantptr++, wsptr++) { 938 /* Even part */ 939 940 tmp0 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]); 941 tmp0 <<= CONST_BITS; 942 /* Add fudge factor here for final descale. */ 943 tmp0 += ONE << (CONST_BITS-PASS1_BITS-1); 944 tmp2 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]); 945 tmp12 = MULTIPLY(tmp2, FIX(0.707106781)); /* c2 */ 946 tmp10 = tmp0 + tmp12; 947 tmp2 = tmp0 - tmp12 - tmp12; 948 949 /* Odd part */ 950 951 tmp12 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]); 952 tmp0 = MULTIPLY(tmp12, FIX(1.224744871)); /* c1 */ 953 954 /* Final output stage */ 955 956 wsptr[3*0] = (int) RIGHT_SHIFT(tmp10 + tmp0, CONST_BITS-PASS1_BITS); 957 wsptr[3*2] = (int) RIGHT_SHIFT(tmp10 - tmp0, CONST_BITS-PASS1_BITS); 958 wsptr[3*1] = (int) RIGHT_SHIFT(tmp2, CONST_BITS-PASS1_BITS); 959 } 960 961 /* Pass 2: process 3 rows from work array, store into output array. */ 962 963 wsptr = workspace; 964 for (ctr = 0; ctr < 3; ctr++) { 965 outptr = output_buf[ctr] + output_col; 966 967 /* Even part */ 968 969 /* Add fudge factor here for final descale. */ 970 tmp0 = (INT32) wsptr[0] + (ONE << (PASS1_BITS+2)); 971 tmp0 <<= CONST_BITS; 972 tmp2 = (INT32) wsptr[2]; 973 tmp12 = MULTIPLY(tmp2, FIX(0.707106781)); /* c2 */ 974 tmp10 = tmp0 + tmp12; 975 tmp2 = tmp0 - tmp12 - tmp12; 976 977 /* Odd part */ 978 979 tmp12 = (INT32) wsptr[1]; 980 tmp0 = MULTIPLY(tmp12, FIX(1.224744871)); /* c1 */ 981 982 /* Final output stage */ 983 984 outptr[0] = range_limit[(int) RIGHT_SHIFT(tmp10 + tmp0, 985 CONST_BITS+PASS1_BITS+3) 986 & RANGE_MASK]; 987 outptr[2] = range_limit[(int) RIGHT_SHIFT(tmp10 - tmp0, 988 CONST_BITS+PASS1_BITS+3) 989 & RANGE_MASK]; 990 outptr[1] = range_limit[(int) RIGHT_SHIFT(tmp2, 991 CONST_BITS+PASS1_BITS+3) 992 & RANGE_MASK]; 993 994 wsptr += 3; /* advance pointer to next row */ 995 } 996} 997 998 999/* 1000 * Perform dequantization and inverse DCT on one block of coefficients, 1001 * producing a reduced-size 2x2 output block. 1002 * 1003 * Multiplication-less algorithm. 1004 */ 1005 1006GLOBAL(void) 1007jpeg_idct_2x2 (j_decompress_ptr cinfo, jpeg_component_info * compptr, 1008 JCOEFPTR coef_block, 1009 JSAMPARRAY output_buf, JDIMENSION output_col) 1010{ 1011 INT32 tmp0, tmp1, tmp2, tmp3, tmp4, tmp5; 1012 ISLOW_MULT_TYPE * quantptr; 1013 JSAMPROW outptr; 1014 JSAMPLE *range_limit = IDCT_range_limit(cinfo); 1015 SHIFT_TEMPS 1016 1017 /* Pass 1: process columns from input. */ 1018 1019 quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table; 1020 1021 /* Column 0 */ 1022 tmp4 = DEQUANTIZE(coef_block[DCTSIZE*0], quantptr[DCTSIZE*0]); 1023 tmp5 = DEQUANTIZE(coef_block[DCTSIZE*1], quantptr[DCTSIZE*1]); 1024 /* Add fudge factor here for final descale. */ 1025 tmp4 += ONE << 2; 1026 1027 tmp0 = tmp4 + tmp5; 1028 tmp2 = tmp4 - tmp5; 1029 1030 /* Column 1 */ 1031 tmp4 = DEQUANTIZE(coef_block[DCTSIZE*0+1], quantptr[DCTSIZE*0+1]); 1032 tmp5 = DEQUANTIZE(coef_block[DCTSIZE*1+1], quantptr[DCTSIZE*1+1]); 1033 1034 tmp1 = tmp4 + tmp5; 1035 tmp3 = tmp4 - tmp5; 1036 1037 /* Pass 2: process 2 rows, store into output array. */ 1038 1039 /* Row 0 */ 1040 outptr = output_buf[0] + output_col; 1041 1042 outptr[0] = range_limit[(int) RIGHT_SHIFT(tmp0 + tmp1, 3) & RANGE_MASK]; 1043 outptr[1] = range_limit[(int) RIGHT_SHIFT(tmp0 - tmp1, 3) & RANGE_MASK]; 1044 1045 /* Row 1 */ 1046 outptr = output_buf[1] + output_col; 1047 1048 outptr[0] = range_limit[(int) RIGHT_SHIFT(tmp2 + tmp3, 3) & RANGE_MASK]; 1049 outptr[1] = range_limit[(int) RIGHT_SHIFT(tmp2 - tmp3, 3) & RANGE_MASK]; 1050} 1051 1052 1053/* 1054 * Perform dequantization and inverse DCT on one block of coefficients, 1055 * producing a reduced-size 1x1 output block. 1056 * 1057 * We hardly need an inverse DCT routine for this: just take the 1058 * average pixel value, which is one-eighth of the DC coefficient. 1059 */ 1060 1061GLOBAL(void) 1062jpeg_idct_1x1 (j_decompress_ptr cinfo, jpeg_component_info * compptr, 1063 JCOEFPTR coef_block, 1064 JSAMPARRAY output_buf, JDIMENSION output_col) 1065{ 1066 int dcval; 1067 ISLOW_MULT_TYPE * quantptr; 1068 JSAMPLE *range_limit = IDCT_range_limit(cinfo); 1069 SHIFT_TEMPS 1070 1071 /* 1x1 is trivial: just take the DC coefficient divided by 8. */ 1072 quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table; 1073 dcval = DEQUANTIZE(coef_block[0], quantptr[0]); 1074 dcval = (int) DESCALE((INT32) dcval, 3); 1075 1076 output_buf[0][output_col] = range_limit[dcval & RANGE_MASK]; 1077} 1078 1079 1080/* 1081 * Perform dequantization and inverse DCT on one block of coefficients, 1082 * producing a 9x9 output block. 1083 * 1084 * Optimized algorithm with 10 multiplications in the 1-D kernel. 1085 * cK represents sqrt(2) * cos(K*pi/18). 1086 */ 1087 1088GLOBAL(void) 1089jpeg_idct_9x9 (j_decompress_ptr cinfo, jpeg_component_info * compptr, 1090 JCOEFPTR coef_block, 1091 JSAMPARRAY output_buf, JDIMENSION output_col) 1092{ 1093 INT32 tmp0, tmp1, tmp2, tmp3, tmp10, tmp11, tmp12, tmp13, tmp14; 1094 INT32 z1, z2, z3, z4; 1095 JCOEFPTR inptr; 1096 ISLOW_MULT_TYPE * quantptr; 1097 int * wsptr; 1098 JSAMPROW outptr; 1099 JSAMPLE *range_limit = IDCT_range_limit(cinfo); 1100 int ctr; 1101 int workspace[8*9]; /* buffers data between passes */ 1102 SHIFT_TEMPS 1103 1104 /* Pass 1: process columns from input, store into work array. */ 1105 1106 inptr = coef_block; 1107 quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table; 1108 wsptr = workspace; 1109 for (ctr = 0; ctr < 8; ctr++, inptr++, quantptr++, wsptr++) { 1110 /* Even part */ 1111 1112 tmp0 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]); 1113 tmp0 <<= CONST_BITS; 1114 /* Add fudge factor here for final descale. */ 1115 tmp0 += ONE << (CONST_BITS-PASS1_BITS-1); 1116 1117 z1 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]); 1118 z2 = DEQUANTIZE(inptr[DCTSIZE*4], quantptr[DCTSIZE*4]); 1119 z3 = DEQUANTIZE(inptr[DCTSIZE*6], quantptr[DCTSIZE*6]); 1120 1121 tmp3 = MULTIPLY(z3, FIX(0.707106781)); /* c6 */ 1122 tmp1 = tmp0 + tmp3; 1123 tmp2 = tmp0 - tmp3 - tmp3; 1124 1125 tmp0 = MULTIPLY(z1 - z2, FIX(0.707106781)); /* c6 */ 1126 tmp11 = tmp2 + tmp0; 1127 tmp14 = tmp2 - tmp0 - tmp0; 1128 1129 tmp0 = MULTIPLY(z1 + z2, FIX(1.328926049)); /* c2 */ 1130 tmp2 = MULTIPLY(z1, FIX(1.083350441)); /* c4 */ 1131 tmp3 = MULTIPLY(z2, FIX(0.245575608)); /* c8 */ 1132 1133 tmp10 = tmp1 + tmp0 - tmp3; 1134 tmp12 = tmp1 - tmp0 + tmp2; 1135 tmp13 = tmp1 - tmp2 + tmp3; 1136 1137 /* Odd part */ 1138 1139 z1 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]); 1140 z2 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]); 1141 z3 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5]); 1142 z4 = DEQUANTIZE(inptr[DCTSIZE*7], quantptr[DCTSIZE*7]); 1143 1144 z2 = MULTIPLY(z2, - FIX(1.224744871)); /* -c3 */ 1145 1146 tmp2 = MULTIPLY(z1 + z3, FIX(0.909038955)); /* c5 */ 1147 tmp3 = MULTIPLY(z1 + z4, FIX(0.483689525)); /* c7 */ 1148 tmp0 = tmp2 + tmp3 - z2; 1149 tmp1 = MULTIPLY(z3 - z4, FIX(1.392728481)); /* c1 */ 1150 tmp2 += z2 - tmp1; 1151 tmp3 += z2 + tmp1; 1152 tmp1 = MULTIPLY(z1 - z3 - z4, FIX(1.224744871)); /* c3 */ 1153 1154 /* Final output stage */ 1155 1156 wsptr[8*0] = (int) RIGHT_SHIFT(tmp10 + tmp0, CONST_BITS-PASS1_BITS); 1157 wsptr[8*8] = (int) RIGHT_SHIFT(tmp10 - tmp0, CONST_BITS-PASS1_BITS); 1158 wsptr[8*1] = (int) RIGHT_SHIFT(tmp11 + tmp1, CONST_BITS-PASS1_BITS); 1159 wsptr[8*7] = (int) RIGHT_SHIFT(tmp11 - tmp1, CONST_BITS-PASS1_BITS); 1160 wsptr[8*2] = (int) RIGHT_SHIFT(tmp12 + tmp2, CONST_BITS-PASS1_BITS); 1161 wsptr[8*6] = (int) RIGHT_SHIFT(tmp12 - tmp2, CONST_BITS-PASS1_BITS); 1162 wsptr[8*3] = (int) RIGHT_SHIFT(tmp13 + tmp3, CONST_BITS-PASS1_BITS); 1163 wsptr[8*5] = (int) RIGHT_SHIFT(tmp13 - tmp3, CONST_BITS-PASS1_BITS); 1164 wsptr[8*4] = (int) RIGHT_SHIFT(tmp14, CONST_BITS-PASS1_BITS); 1165 } 1166 1167 /* Pass 2: process 9 rows from work array, store into output array. */ 1168 1169 wsptr = workspace; 1170 for (ctr = 0; ctr < 9; ctr++) { 1171 outptr = output_buf[ctr] + output_col; 1172 1173 /* Even part */ 1174 1175 /* Add fudge factor here for final descale. */ 1176 tmp0 = (INT32) wsptr[0] + (ONE << (PASS1_BITS+2)); 1177 tmp0 <<= CONST_BITS; 1178 1179 z1 = (INT32) wsptr[2]; 1180 z2 = (INT32) wsptr[4]; 1181 z3 = (INT32) wsptr[6]; 1182 1183 tmp3 = MULTIPLY(z3, FIX(0.707106781)); /* c6 */ 1184 tmp1 = tmp0 + tmp3; 1185 tmp2 = tmp0 - tmp3 - tmp3; 1186 1187 tmp0 = MULTIPLY(z1 - z2, FIX(0.707106781)); /* c6 */ 1188 tmp11 = tmp2 + tmp0; 1189 tmp14 = tmp2 - tmp0 - tmp0; 1190 1191 tmp0 = MULTIPLY(z1 + z2, FIX(1.328926049)); /* c2 */ 1192 tmp2 = MULTIPLY(z1, FIX(1.083350441)); /* c4 */ 1193 tmp3 = MULTIPLY(z2, FIX(0.245575608)); /* c8 */ 1194 1195 tmp10 = tmp1 + tmp0 - tmp3; 1196 tmp12 = tmp1 - tmp0 + tmp2; 1197 tmp13 = tmp1 - tmp2 + tmp3; 1198 1199 /* Odd part */ 1200 1201 z1 = (INT32) wsptr[1]; 1202 z2 = (INT32) wsptr[3]; 1203 z3 = (INT32) wsptr[5]; 1204 z4 = (INT32) wsptr[7]; 1205 1206 z2 = MULTIPLY(z2, - FIX(1.224744871)); /* -c3 */ 1207 1208 tmp2 = MULTIPLY(z1 + z3, FIX(0.909038955)); /* c5 */ 1209 tmp3 = MULTIPLY(z1 + z4, FIX(0.483689525)); /* c7 */ 1210 tmp0 = tmp2 + tmp3 - z2; 1211 tmp1 = MULTIPLY(z3 - z4, FIX(1.392728481)); /* c1 */ 1212 tmp2 += z2 - tmp1; 1213 tmp3 += z2 + tmp1; 1214 tmp1 = MULTIPLY(z1 - z3 - z4, FIX(1.224744871)); /* c3 */ 1215 1216 /* Final output stage */ 1217 1218 outptr[0] = range_limit[(int) RIGHT_SHIFT(tmp10 + tmp0, 1219 CONST_BITS+PASS1_BITS+3) 1220 & RANGE_MASK]; 1221 outptr[8] = range_limit[(int) RIGHT_SHIFT(tmp10 - tmp0, 1222 CONST_BITS+PASS1_BITS+3) 1223 & RANGE_MASK]; 1224 outptr[1] = range_limit[(int) RIGHT_SHIFT(tmp11 + tmp1, 1225 CONST_BITS+PASS1_BITS+3) 1226 & RANGE_MASK]; 1227 outptr[7] = range_limit[(int) RIGHT_SHIFT(tmp11 - tmp1, 1228 CONST_BITS+PASS1_BITS+3) 1229 & RANGE_MASK]; 1230 outptr[2] = range_limit[(int) RIGHT_SHIFT(tmp12 + tmp2, 1231 CONST_BITS+PASS1_BITS+3) 1232 & RANGE_MASK]; 1233 outptr[6] = range_limit[(int) RIGHT_SHIFT(tmp12 - tmp2, 1234 CONST_BITS+PASS1_BITS+3) 1235 & RANGE_MASK]; 1236 outptr[3] = range_limit[(int) RIGHT_SHIFT(tmp13 + tmp3, 1237 CONST_BITS+PASS1_BITS+3) 1238 & RANGE_MASK]; 1239 outptr[5] = range_limit[(int) RIGHT_SHIFT(tmp13 - tmp3, 1240 CONST_BITS+PASS1_BITS+3) 1241 & RANGE_MASK]; 1242 outptr[4] = range_limit[(int) RIGHT_SHIFT(tmp14, 1243 CONST_BITS+PASS1_BITS+3) 1244 & RANGE_MASK]; 1245 1246 wsptr += 8; /* advance pointer to next row */ 1247 } 1248} 1249 1250 1251/* 1252 * Perform dequantization and inverse DCT on one block of coefficients, 1253 * producing a 10x10 output block. 1254 * 1255 * Optimized algorithm with 12 multiplications in the 1-D kernel. 1256 * cK represents sqrt(2) * cos(K*pi/20). 1257 */ 1258 1259GLOBAL(void) 1260jpeg_idct_10x10 (j_decompress_ptr cinfo, jpeg_component_info * compptr, 1261 JCOEFPTR coef_block, 1262 JSAMPARRAY output_buf, JDIMENSION output_col) 1263{ 1264 INT32 tmp10, tmp11, tmp12, tmp13, tmp14; 1265 INT32 tmp20, tmp21, tmp22, tmp23, tmp24; 1266 INT32 z1, z2, z3, z4, z5; 1267 JCOEFPTR inptr; 1268 ISLOW_MULT_TYPE * quantptr; 1269 int * wsptr; 1270 JSAMPROW outptr; 1271 JSAMPLE *range_limit = IDCT_range_limit(cinfo); 1272 int ctr; 1273 int workspace[8*10]; /* buffers data between passes */ 1274 SHIFT_TEMPS 1275 1276 /* Pass 1: process columns from input, store into work array. */ 1277 1278 inptr = coef_block; 1279 quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table; 1280 wsptr = workspace; 1281 for (ctr = 0; ctr < 8; ctr++, inptr++, quantptr++, wsptr++) { 1282 /* Even part */ 1283 1284 z3 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]); 1285 z3 <<= CONST_BITS; 1286 /* Add fudge factor here for final descale. */ 1287 z3 += ONE << (CONST_BITS-PASS1_BITS-1); 1288 z4 = DEQUANTIZE(inptr[DCTSIZE*4], quantptr[DCTSIZE*4]); 1289 z1 = MULTIPLY(z4, FIX(1.144122806)); /* c4 */ 1290 z2 = MULTIPLY(z4, FIX(0.437016024)); /* c8 */ 1291 tmp10 = z3 + z1; 1292 tmp11 = z3 - z2; 1293 1294 tmp22 = RIGHT_SHIFT(z3 - ((z1 - z2) << 1), /* c0 = (c4-c8)*2 */ 1295 CONST_BITS-PASS1_BITS); 1296 1297 z2 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]); 1298 z3 = DEQUANTIZE(inptr[DCTSIZE*6], quantptr[DCTSIZE*6]); 1299 1300 z1 = MULTIPLY(z2 + z3, FIX(0.831253876)); /* c6 */ 1301 tmp12 = z1 + MULTIPLY(z2, FIX(0.513743148)); /* c2-c6 */ 1302 tmp13 = z1 - MULTIPLY(z3, FIX(2.176250899)); /* c2+c6 */ 1303 1304 tmp20 = tmp10 + tmp12; 1305 tmp24 = tmp10 - tmp12; 1306 tmp21 = tmp11 + tmp13; 1307 tmp23 = tmp11 - tmp13; 1308 1309 /* Odd part */ 1310 1311 z1 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]); 1312 z2 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]); 1313 z3 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5]); 1314 z4 = DEQUANTIZE(inptr[DCTSIZE*7], quantptr[DCTSIZE*7]); 1315 1316 tmp11 = z2 + z4; 1317 tmp13 = z2 - z4; 1318 1319 tmp12 = MULTIPLY(tmp13, FIX(0.309016994)); /* (c3-c7)/2 */ 1320 z5 = z3 << CONST_BITS; 1321 1322 z2 = MULTIPLY(tmp11, FIX(0.951056516)); /* (c3+c7)/2 */ 1323 z4 = z5 + tmp12; 1324 1325 tmp10 = MULTIPLY(z1, FIX(1.396802247)) + z2 + z4; /* c1 */ 1326 tmp14 = MULTIPLY(z1, FIX(0.221231742)) - z2 + z4; /* c9 */ 1327 1328 z2 = MULTIPLY(tmp11, FIX(0.587785252)); /* (c1-c9)/2 */ 1329 z4 = z5 - tmp12 - (tmp13 << (CONST_BITS - 1)); 1330 1331 tmp12 = (z1 - tmp13 - z3) << PASS1_BITS; 1332 1333 tmp11 = MULTIPLY(z1, FIX(1.260073511)) - z2 - z4; /* c3 */ 1334 tmp13 = MULTIPLY(z1, FIX(0.642039522)) - z2 + z4; /* c7 */ 1335 1336 /* Final output stage */ 1337 1338 wsptr[8*0] = (int) RIGHT_SHIFT(tmp20 + tmp10, CONST_BITS-PASS1_BITS); 1339 wsptr[8*9] = (int) RIGHT_SHIFT(tmp20 - tmp10, CONST_BITS-PASS1_BITS); 1340 wsptr[8*1] = (int) RIGHT_SHIFT(tmp21 + tmp11, CONST_BITS-PASS1_BITS); 1341 wsptr[8*8] = (int) RIGHT_SHIFT(tmp21 - tmp11, CONST_BITS-PASS1_BITS); 1342 wsptr[8*2] = (int) (tmp22 + tmp12); 1343 wsptr[8*7] = (int) (tmp22 - tmp12); 1344 wsptr[8*3] = (int) RIGHT_SHIFT(tmp23 + tmp13, CONST_BITS-PASS1_BITS); 1345 wsptr[8*6] = (int) RIGHT_SHIFT(tmp23 - tmp13, CONST_BITS-PASS1_BITS); 1346 wsptr[8*4] = (int) RIGHT_SHIFT(tmp24 + tmp14, CONST_BITS-PASS1_BITS); 1347 wsptr[8*5] = (int) RIGHT_SHIFT(tmp24 - tmp14, CONST_BITS-PASS1_BITS); 1348 } 1349 1350 /* Pass 2: process 10 rows from work array, store into output array. */ 1351 1352 wsptr = workspace; 1353 for (ctr = 0; ctr < 10; ctr++) { 1354 outptr = output_buf[ctr] + output_col; 1355 1356 /* Even part */ 1357 1358 /* Add fudge factor here for final descale. */ 1359 z3 = (INT32) wsptr[0] + (ONE << (PASS1_BITS+2)); 1360 z3 <<= CONST_BITS; 1361 z4 = (INT32) wsptr[4]; 1362 z1 = MULTIPLY(z4, FIX(1.144122806)); /* c4 */ 1363 z2 = MULTIPLY(z4, FIX(0.437016024)); /* c8 */ 1364 tmp10 = z3 + z1; 1365 tmp11 = z3 - z2; 1366 1367 tmp22 = z3 - ((z1 - z2) << 1); /* c0 = (c4-c8)*2 */ 1368 1369 z2 = (INT32) wsptr[2]; 1370 z3 = (INT32) wsptr[6]; 1371 1372 z1 = MULTIPLY(z2 + z3, FIX(0.831253876)); /* c6 */ 1373 tmp12 = z1 + MULTIPLY(z2, FIX(0.513743148)); /* c2-c6 */ 1374 tmp13 = z1 - MULTIPLY(z3, FIX(2.176250899)); /* c2+c6 */ 1375 1376 tmp20 = tmp10 + tmp12; 1377 tmp24 = tmp10 - tmp12; 1378 tmp21 = tmp11 + tmp13; 1379 tmp23 = tmp11 - tmp13; 1380 1381 /* Odd part */ 1382 1383 z1 = (INT32) wsptr[1]; 1384 z2 = (INT32) wsptr[3]; 1385 z3 = (INT32) wsptr[5]; 1386 z3 <<= CONST_BITS; 1387 z4 = (INT32) wsptr[7]; 1388 1389 tmp11 = z2 + z4; 1390 tmp13 = z2 - z4; 1391 1392 tmp12 = MULTIPLY(tmp13, FIX(0.309016994)); /* (c3-c7)/2 */ 1393 1394 z2 = MULTIPLY(tmp11, FIX(0.951056516)); /* (c3+c7)/2 */ 1395 z4 = z3 + tmp12; 1396 1397 tmp10 = MULTIPLY(z1, FIX(1.396802247)) + z2 + z4; /* c1 */ 1398 tmp14 = MULTIPLY(z1, FIX(0.221231742)) - z2 + z4; /* c9 */ 1399 1400 z2 = MULTIPLY(tmp11, FIX(0.587785252)); /* (c1-c9)/2 */ 1401 z4 = z3 - tmp12 - (tmp13 << (CONST_BITS - 1)); 1402 1403 tmp12 = ((z1 - tmp13) << CONST_BITS) - z3; 1404 1405 tmp11 = MULTIPLY(z1, FIX(1.260073511)) - z2 - z4; /* c3 */ 1406 tmp13 = MULTIPLY(z1, FIX(0.642039522)) - z2 + z4; /* c7 */ 1407 1408 /* Final output stage */ 1409 1410 outptr[0] = range_limit[(int) RIGHT_SHIFT(tmp20 + tmp10, 1411 CONST_BITS+PASS1_BITS+3) 1412 & RANGE_MASK]; 1413 outptr[9] = range_limit[(int) RIGHT_SHIFT(tmp20 - tmp10, 1414 CONST_BITS+PASS1_BITS+3) 1415 & RANGE_MASK]; 1416 outptr[1] = range_limit[(int) RIGHT_SHIFT(tmp21 + tmp11, 1417 CONST_BITS+PASS1_BITS+3) 1418 & RANGE_MASK]; 1419 outptr[8] = range_limit[(int) RIGHT_SHIFT(tmp21 - tmp11, 1420 CONST_BITS+PASS1_BITS+3) 1421 & RANGE_MASK]; 1422 outptr[2] = range_limit[(int) RIGHT_SHIFT(tmp22 + tmp12, 1423 CONST_BITS+PASS1_BITS+3) 1424 & RANGE_MASK]; 1425 outptr[7] = range_limit[(int) RIGHT_SHIFT(tmp22 - tmp12, 1426 CONST_BITS+PASS1_BITS+3) 1427 & RANGE_MASK]; 1428 outptr[3] = range_limit[(int) RIGHT_SHIFT(tmp23 + tmp13, 1429 CONST_BITS+PASS1_BITS+3) 1430 & RANGE_MASK]; 1431 outptr[6] = range_limit[(int) RIGHT_SHIFT(tmp23 - tmp13, 1432 CONST_BITS+PASS1_BITS+3) 1433 & RANGE_MASK]; 1434 outptr[4] = range_limit[(int) RIGHT_SHIFT(tmp24 + tmp14, 1435 CONST_BITS+PASS1_BITS+3) 1436 & RANGE_MASK]; 1437 outptr[5] = range_limit[(int) RIGHT_SHIFT(tmp24 - tmp14, 1438 CONST_BITS+PASS1_BITS+3) 1439 & RANGE_MASK]; 1440 1441 wsptr += 8; /* advance pointer to next row */ 1442 } 1443} 1444 1445 1446/* 1447 * Perform dequantization and inverse DCT on one block of coefficients, 1448 * producing a 11x11 output block. 1449 * 1450 * Optimized algorithm with 24 multiplications in the 1-D kernel. 1451 * cK represents sqrt(2) * cos(K*pi/22). 1452 */ 1453 1454GLOBAL(void) 1455jpeg_idct_11x11 (j_decompress_ptr cinfo, jpeg_component_info * compptr, 1456 JCOEFPTR coef_block, 1457 JSAMPARRAY output_buf, JDIMENSION output_col) 1458{ 1459 INT32 tmp10, tmp11, tmp…
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