1ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#if !defined(_FX_JPEG_TURBO_) 2ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov/* 3ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * jidctfst.c 4ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * 5ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * Copyright (C) 1994-1998, Thomas G. Lane. 6ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * This file is part of the Independent JPEG Group's software. 7ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * For conditions of distribution and use, see the accompanying README file. 8ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * 9ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * This file contains a fast, not so accurate integer implementation of the 10ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * inverse DCT (Discrete Cosine Transform). In the IJG code, this routine 11ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * must also perform dequantization of the input coefficients. 12ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * 13ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * A 2-D IDCT can be done by 1-D IDCT on each column followed by 1-D IDCT 14ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * on each row (or vice versa, but it's more convenient to emit a row at 15ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * a time). Direct algorithms are also available, but they are much more 16ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * complex and seem not to be any faster when reduced to code. 17ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * 18ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * This implementation is based on Arai, Agui, and Nakajima's algorithm for 19ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * scaled DCT. Their original paper (Trans. IEICE E-71(11):1095) is in 20ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * Japanese, but the algorithm is described in the Pennebaker & Mitchell 21ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * JPEG textbook (see REFERENCES section in file README). The following code 22ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * is based directly on figure 4-8 in P&M. 23ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * While an 8-point DCT cannot be done in less than 11 multiplies, it is 24ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * possible to arrange the computation so that many of the multiplies are 25ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * simple scalings of the final outputs. These multiplies can then be 26ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * folded into the multiplications or divisions by the JPEG quantization 27ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * table entries. The AA&N method leaves only 5 multiplies and 29 adds 28ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * to be done in the DCT itself. 29ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * The primary disadvantage of this method is that with fixed-point math, 30ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * accuracy is lost due to imprecise representation of the scaled 31ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * quantization values. The smaller the quantization table entry, the less 32ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * precise the scaled value, so this implementation does worse with high- 33ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * quality-setting files than with low-quality ones. 34ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov */ 35ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 36ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#define JPEG_INTERNALS 37ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#include "jinclude.h" 38ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#include "jpeglib.h" 39ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#include "jdct.h" /* Private declarations for DCT subsystem */ 40ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 41ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#ifdef DCT_IFAST_SUPPORTED 42ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 43ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 44ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov/* 45ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * This module is specialized to the case DCTSIZE = 8. 46ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov */ 47ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 48ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#if DCTSIZE != 8 49ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */ 50ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#endif 51ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 52ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 53ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov/* Scaling decisions are generally the same as in the LL&M algorithm; 54ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * see jidctint.c for more details. However, we choose to descale 55ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * (right shift) multiplication products as soon as they are formed, 56ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * rather than carrying additional fractional bits into subsequent additions. 57ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * This compromises accuracy slightly, but it lets us save a few shifts. 58ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * More importantly, 16-bit arithmetic is then adequate (for 8-bit samples) 59ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * everywhere except in the multiplications proper; this saves a good deal 60ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * of work on 16-bit-int machines. 61ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * 62ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * The dequantized coefficients are not integers because the AA&N scaling 63ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * factors have been incorporated. We represent them scaled up by PASS1_BITS, 64ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * so that the first and second IDCT rounds have the same input scaling. 65ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * For 8-bit JSAMPLEs, we choose IFAST_SCALE_BITS = PASS1_BITS so as to 66ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * avoid a descaling shift; this compromises accuracy rather drastically 67ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * for small quantization table entries, but it saves a lot of shifts. 68ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * For 12-bit JSAMPLEs, there's no hope of using 16x16 multiplies anyway, 69ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * so we use a much larger scaling factor to preserve accuracy. 70ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * 71ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * A final compromise is to represent the multiplicative constants to only 72ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * 8 fractional bits, rather than 13. This saves some shifting work on some 73ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * machines, and may also reduce the cost of multiplication (since there 74ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * are fewer one-bits in the constants). 75ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov */ 76ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 77ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#if BITS_IN_JSAMPLE == 8 78ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#define CONST_BITS 8 79ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#define PASS1_BITS 2 80ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#else 81ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#define CONST_BITS 8 82ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#define PASS1_BITS 1 /* lose a little precision to avoid overflow */ 83ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#endif 84ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 85ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov/* Some C compilers fail to reduce "FIX(constant)" at compile time, thus 86ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * causing a lot of useless floating-point operations at run time. 87ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * To get around this we use the following pre-calculated constants. 88ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * If you change CONST_BITS you may want to add appropriate values. 89ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * (With a reasonable C compiler, you can just rely on the FIX() macro...) 90ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov */ 91ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 92ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#if CONST_BITS == 8 93ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#define FIX_1_082392200 ((INT32) 277) /* FIX(1.082392200) */ 94ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#define FIX_1_414213562 ((INT32) 362) /* FIX(1.414213562) */ 95ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#define FIX_1_847759065 ((INT32) 473) /* FIX(1.847759065) */ 96ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#define FIX_2_613125930 ((INT32) 669) /* FIX(2.613125930) */ 97ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#else 98ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#define FIX_1_082392200 FIX(1.082392200) 99ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#define FIX_1_414213562 FIX(1.414213562) 100ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#define FIX_1_847759065 FIX(1.847759065) 101ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#define FIX_2_613125930 FIX(2.613125930) 102ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#endif 103ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 104ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 105ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov/* We can gain a little more speed, with a further compromise in accuracy, 106ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * by omitting the addition in a descaling shift. This yields an incorrectly 107ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * rounded result half the time... 108ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov */ 109ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 110ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#ifndef USE_ACCURATE_ROUNDING 111ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#undef DESCALE 112ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#define DESCALE(x,n) RIGHT_SHIFT(x, n) 113ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#endif 114ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 115ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 116ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov/* Multiply a DCTELEM variable by an INT32 constant, and immediately 117ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * descale to yield a DCTELEM result. 118ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov */ 119ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 120ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#define MULTIPLY(var,const) ((DCTELEM) DESCALE((var) * (const), CONST_BITS)) 121ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 122ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 123ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov/* Dequantize a coefficient by multiplying it by the multiplier-table 124ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * entry; produce a DCTELEM result. For 8-bit data a 16x16->16 125ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * multiplication will do. For 12-bit data, the multiplier table is 126ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * declared INT32, so a 32-bit multiply will be used. 127ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov */ 128ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 129ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#if BITS_IN_JSAMPLE == 8 130ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#define DEQUANTIZE(coef,quantval) (((IFAST_MULT_TYPE) (coef)) * (quantval)) 131ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#else 132ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#define DEQUANTIZE(coef,quantval) \ 133ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov DESCALE((coef)*(quantval), IFAST_SCALE_BITS-PASS1_BITS) 134ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#endif 135ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 136ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 137ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov/* Like DESCALE, but applies to a DCTELEM and produces an int. 138ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * We assume that int right shift is unsigned if INT32 right shift is. 139ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov */ 140ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 141ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#ifdef RIGHT_SHIFT_IS_UNSIGNED 142ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#define ISHIFT_TEMPS DCTELEM ishift_temp; 143ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#if BITS_IN_JSAMPLE == 8 144ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#define DCTELEMBITS 16 /* DCTELEM may be 16 or 32 bits */ 145ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#else 146ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#define DCTELEMBITS 32 /* DCTELEM must be 32 bits */ 147ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#endif 148ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#define IRIGHT_SHIFT(x,shft) \ 149ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov ((ishift_temp = (x)) < 0 ? \ 150ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov (ishift_temp >> (shft)) | ((~((DCTELEM) 0)) << (DCTELEMBITS-(shft))) : \ 151ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov (ishift_temp >> (shft))) 152ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#else 153ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#define ISHIFT_TEMPS 154ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#define IRIGHT_SHIFT(x,shft) ((x) >> (shft)) 155ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#endif 156ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 157ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#ifdef USE_ACCURATE_ROUNDING 158ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#define IDESCALE(x,n) ((int) IRIGHT_SHIFT((x) + (1 << ((n)-1)), n)) 159ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#else 160ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#define IDESCALE(x,n) ((int) IRIGHT_SHIFT(x, n)) 161ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#endif 162ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 163ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 164ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov/* 165ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * Perform dequantization and inverse DCT on one block of coefficients. 166ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov */ 167ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 168ee451cb395940862dad63c85adfe8f2fd55e864cSvet GanovGLOBAL(void) 169ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganovjpeg_idct_ifast (j_decompress_ptr cinfo, jpeg_component_info * compptr, 170ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov JCOEFPTR coef_block, 171ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov JSAMPARRAY output_buf, JDIMENSION output_col) 172ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov{ 173ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov DCTELEM tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7; 174ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov DCTELEM tmp10, tmp11, tmp12, tmp13; 175ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov DCTELEM z5, z10, z11, z12, z13; 176ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov JCOEFPTR inptr; 177ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov IFAST_MULT_TYPE * quantptr; 178ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov int * wsptr; 179ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov JSAMPROW outptr; 180ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov JSAMPLE *range_limit = IDCT_range_limit(cinfo); 181ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov int ctr; 182ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov int workspace[DCTSIZE2]; /* buffers data between passes */ 183ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov SHIFT_TEMPS /* for DESCALE */ 184ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov ISHIFT_TEMPS /* for IDESCALE */ 185ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 186ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov /* Pass 1: process columns from input, store into work array. */ 187ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 188ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov inptr = coef_block; 189ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov quantptr = (IFAST_MULT_TYPE *) compptr->dct_table; 190ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov wsptr = workspace; 191ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov for (ctr = DCTSIZE; ctr > 0; ctr--) { 192ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov /* Due to quantization, we will usually find that many of the input 193ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * coefficients are zero, especially the AC terms. We can exploit this 194ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * by short-circuiting the IDCT calculation for any column in which all 195ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * the AC terms are zero. In that case each output is equal to the 196ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * DC coefficient (with scale factor as needed). 197ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * With typical images and quantization tables, half or more of the 198ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * column DCT calculations can be simplified this way. 199ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov */ 200ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 201ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (inptr[DCTSIZE*1] == 0 && inptr[DCTSIZE*2] == 0 && 202ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov inptr[DCTSIZE*3] == 0 && inptr[DCTSIZE*4] == 0 && 203ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov inptr[DCTSIZE*5] == 0 && inptr[DCTSIZE*6] == 0 && 204ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov inptr[DCTSIZE*7] == 0) { 205ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov /* AC terms all zero */ 206ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov int dcval = (int) DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]); 207ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 208ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov wsptr[DCTSIZE*0] = dcval; 209ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov wsptr[DCTSIZE*1] = dcval; 210ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov wsptr[DCTSIZE*2] = dcval; 211ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov wsptr[DCTSIZE*3] = dcval; 212ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov wsptr[DCTSIZE*4] = dcval; 213ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov wsptr[DCTSIZE*5] = dcval; 214ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov wsptr[DCTSIZE*6] = dcval; 215ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov wsptr[DCTSIZE*7] = dcval; 216ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 217ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov inptr++; /* advance pointers to next column */ 218ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov quantptr++; 219ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov wsptr++; 220ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov continue; 221ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 222ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 223ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov /* Even part */ 224ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 225ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp0 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]); 226ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp1 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]); 227ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp2 = DEQUANTIZE(inptr[DCTSIZE*4], quantptr[DCTSIZE*4]); 228ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp3 = DEQUANTIZE(inptr[DCTSIZE*6], quantptr[DCTSIZE*6]); 229ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 230ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp10 = tmp0 + tmp2; /* phase 3 */ 231ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp11 = tmp0 - tmp2; 232ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 233ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp13 = tmp1 + tmp3; /* phases 5-3 */ 234ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp12 = MULTIPLY(tmp1 - tmp3, FIX_1_414213562) - tmp13; /* 2*c4 */ 235ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 236ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp0 = tmp10 + tmp13; /* phase 2 */ 237ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp3 = tmp10 - tmp13; 238ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp1 = tmp11 + tmp12; 239ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp2 = tmp11 - tmp12; 240ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 241ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov /* Odd part */ 242ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 243ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp4 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]); 244ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp5 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]); 245ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp6 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5]); 246ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp7 = DEQUANTIZE(inptr[DCTSIZE*7], quantptr[DCTSIZE*7]); 247ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 248ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov z13 = tmp6 + tmp5; /* phase 6 */ 249ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov z10 = tmp6 - tmp5; 250ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov z11 = tmp4 + tmp7; 251ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov z12 = tmp4 - tmp7; 252ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 253ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp7 = z11 + z13; /* phase 5 */ 254ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp11 = MULTIPLY(z11 - z13, FIX_1_414213562); /* 2*c4 */ 255ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 256ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov z5 = MULTIPLY(z10 + z12, FIX_1_847759065); /* 2*c2 */ 257ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp10 = MULTIPLY(z12, FIX_1_082392200) - z5; /* 2*(c2-c6) */ 258ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp12 = MULTIPLY(z10, - FIX_2_613125930) + z5; /* -2*(c2+c6) */ 259ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 260ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp6 = tmp12 - tmp7; /* phase 2 */ 261ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp5 = tmp11 - tmp6; 262ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp4 = tmp10 + tmp5; 263ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 264ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov wsptr[DCTSIZE*0] = (int) (tmp0 + tmp7); 265ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov wsptr[DCTSIZE*7] = (int) (tmp0 - tmp7); 266ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov wsptr[DCTSIZE*1] = (int) (tmp1 + tmp6); 267ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov wsptr[DCTSIZE*6] = (int) (tmp1 - tmp6); 268ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov wsptr[DCTSIZE*2] = (int) (tmp2 + tmp5); 269ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov wsptr[DCTSIZE*5] = (int) (tmp2 - tmp5); 270ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov wsptr[DCTSIZE*4] = (int) (tmp3 + tmp4); 271ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov wsptr[DCTSIZE*3] = (int) (tmp3 - tmp4); 272ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 273ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov inptr++; /* advance pointers to next column */ 274ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov quantptr++; 275ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov wsptr++; 276ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 277ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 278ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov /* Pass 2: process rows from work array, store into output array. */ 279ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov /* Note that we must descale the results by a factor of 8 == 2**3, */ 280ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov /* and also undo the PASS1_BITS scaling. */ 281ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 282ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov wsptr = workspace; 283ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov for (ctr = 0; ctr < DCTSIZE; ctr++) { 284ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov outptr = output_buf[ctr] + output_col; 285ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov /* Rows of zeroes can be exploited in the same way as we did with columns. 286ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * However, the column calculation has created many nonzero AC terms, so 287ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * the simplification applies less often (typically 5% to 10% of the time). 288ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * On machines with very fast multiplication, it's possible that the 289ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * test takes more time than it's worth. In that case this section 290ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov * may be commented out. 291ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov */ 292ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 293ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#ifndef NO_ZERO_ROW_TEST 294ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (wsptr[1] == 0 && wsptr[2] == 0 && wsptr[3] == 0 && wsptr[4] == 0 && 295ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov wsptr[5] == 0 && wsptr[6] == 0 && wsptr[7] == 0) { 296ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov /* AC terms all zero */ 297ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov JSAMPLE dcval = range_limit[IDESCALE(wsptr[0], PASS1_BITS+3) 298ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov & RANGE_MASK]; 299ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 300ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov outptr[0] = dcval; 301ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov outptr[1] = dcval; 302ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov outptr[2] = dcval; 303ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov outptr[3] = dcval; 304ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov outptr[4] = dcval; 305ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov outptr[5] = dcval; 306ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov outptr[6] = dcval; 307ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov outptr[7] = dcval; 308ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 309ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov wsptr += DCTSIZE; /* advance pointer to next row */ 310ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov continue; 311ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 312ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#endif 313ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 314ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov /* Even part */ 315ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 316ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp10 = ((DCTELEM) wsptr[0] + (DCTELEM) wsptr[4]); 317ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp11 = ((DCTELEM) wsptr[0] - (DCTELEM) wsptr[4]); 318ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 319ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp13 = ((DCTELEM) wsptr[2] + (DCTELEM) wsptr[6]); 320ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp12 = MULTIPLY((DCTELEM) wsptr[2] - (DCTELEM) wsptr[6], FIX_1_414213562) 321ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov - tmp13; 322ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 323ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp0 = tmp10 + tmp13; 324ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp3 = tmp10 - tmp13; 325ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp1 = tmp11 + tmp12; 326ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp2 = tmp11 - tmp12; 327ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 328ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov /* Odd part */ 329ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 330ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov z13 = (DCTELEM) wsptr[5] + (DCTELEM) wsptr[3]; 331ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov z10 = (DCTELEM) wsptr[5] - (DCTELEM) wsptr[3]; 332ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov z11 = (DCTELEM) wsptr[1] + (DCTELEM) wsptr[7]; 333ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov z12 = (DCTELEM) wsptr[1] - (DCTELEM) wsptr[7]; 334ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 335ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp7 = z11 + z13; /* phase 5 */ 336ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp11 = MULTIPLY(z11 - z13, FIX_1_414213562); /* 2*c4 */ 337ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 338ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov z5 = MULTIPLY(z10 + z12, FIX_1_847759065); /* 2*c2 */ 339ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp10 = MULTIPLY(z12, FIX_1_082392200) - z5; /* 2*(c2-c6) */ 340ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp12 = MULTIPLY(z10, - FIX_2_613125930) + z5; /* -2*(c2+c6) */ 341ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 342ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp6 = tmp12 - tmp7; /* phase 2 */ 343ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp5 = tmp11 - tmp6; 344ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov tmp4 = tmp10 + tmp5; 345ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 346ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov /* Final output stage: scale down by a factor of 8 and range-limit */ 347ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 348ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov outptr[0] = range_limit[IDESCALE(tmp0 + tmp7, PASS1_BITS+3) 349ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov & RANGE_MASK]; 350ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov outptr[7] = range_limit[IDESCALE(tmp0 - tmp7, PASS1_BITS+3) 351ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov & RANGE_MASK]; 352ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov outptr[1] = range_limit[IDESCALE(tmp1 + tmp6, PASS1_BITS+3) 353ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov & RANGE_MASK]; 354ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov outptr[6] = range_limit[IDESCALE(tmp1 - tmp6, PASS1_BITS+3) 355ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov & RANGE_MASK]; 356ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov outptr[2] = range_limit[IDESCALE(tmp2 + tmp5, PASS1_BITS+3) 357ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov & RANGE_MASK]; 358ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov outptr[5] = range_limit[IDESCALE(tmp2 - tmp5, PASS1_BITS+3) 359ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov & RANGE_MASK]; 360ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov outptr[4] = range_limit[IDESCALE(tmp3 + tmp4, PASS1_BITS+3) 361ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov & RANGE_MASK]; 362ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov outptr[3] = range_limit[IDESCALE(tmp3 - tmp4, PASS1_BITS+3) 363ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov & RANGE_MASK]; 364ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 365ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov wsptr += DCTSIZE; /* advance pointer to next row */ 366ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 367ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov} 368ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 369ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#endif /* DCT_IFAST_SUPPORTED */ 370ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 371ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#endif //_FX_JPEG_TURBO_ 372