19f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* 29f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * jidctflt.c 39f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * 49f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Copyright (C) 1994-1998, Thomas G. Lane. 59f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * This file is part of the Independent JPEG Group's software. 69f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * For conditions of distribution and use, see the accompanying README file. 79f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * 89f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * This file contains a floating-point implementation of the 99f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * inverse DCT (Discrete Cosine Transform). In the IJG code, this routine 109f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * must also perform dequantization of the input coefficients. 119f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * 129f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * This implementation should be more accurate than either of the integer 139f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * IDCT implementations. However, it may not give the same results on all 149f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * machines because of differences in roundoff behavior. Speed will depend 159f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * on the hardware's floating point capacity. 169f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * 179f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * A 2-D IDCT can be done by 1-D IDCT on each column followed by 1-D IDCT 189f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * on each row (or vice versa, but it's more convenient to emit a row at 199f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * a time). Direct algorithms are also available, but they are much more 209f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * complex and seem not to be any faster when reduced to code. 219f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * 229f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * This implementation is based on Arai, Agui, and Nakajima's algorithm for 239f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * scaled DCT. Their original paper (Trans. IEICE E-71(11):1095) is in 249f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Japanese, but the algorithm is described in the Pennebaker & Mitchell 259f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * JPEG textbook (see REFERENCES section in file README). The following code 269f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * is based directly on figure 4-8 in P&M. 279f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * While an 8-point DCT cannot be done in less than 11 multiplies, it is 289f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * possible to arrange the computation so that many of the multiplies are 299f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * simple scalings of the final outputs. These multiplies can then be 309f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * folded into the multiplications or divisions by the JPEG quantization 319f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * table entries. The AA&N method leaves only 5 multiplies and 29 adds 329f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * to be done in the DCT itself. 339f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * The primary disadvantage of this method is that with a fixed-point 349f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * implementation, accuracy is lost due to imprecise representation of the 359f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * scaled quantization values. However, that problem does not arise if 369f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * we use floating point arithmetic. 379f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 389f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 399f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define JPEG_INTERNALS 409f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#include "jinclude.h" 419f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#include "jpeglib.h" 429f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#include "jdct.h" /* Private declarations for DCT subsystem */ 439f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 449f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#ifdef DCT_FLOAT_SUPPORTED 459f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 469f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 479f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* 489f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * This module is specialized to the case DCTSIZE = 8. 499f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 509f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 519f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#if DCTSIZE != 8 529f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */ 539f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#endif 549f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 559f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 569f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* Dequantize a coefficient by multiplying it by the multiplier-table 579f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * entry; produce a float result. 589f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 599f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 609f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define DEQUANTIZE(coef,quantval) (((FAST_FLOAT) (coef)) * (quantval)) 619f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 629f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 639f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* 649f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Perform dequantization and inverse DCT on one block of coefficients. 659f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 669f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 679f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source ProjectGLOBAL(void) 689f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Projectjpeg_idct_float (j_decompress_ptr cinfo, jpeg_component_info * compptr, 699f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project JCOEFPTR coef_block, 709f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project JSAMPARRAY output_buf, JDIMENSION output_col) 719f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project{ 729f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project FAST_FLOAT tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7; 739f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project FAST_FLOAT tmp10, tmp11, tmp12, tmp13; 749f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project FAST_FLOAT z5, z10, z11, z12, z13; 759f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project JCOEFPTR inptr; 769f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project FLOAT_MULT_TYPE * quantptr; 779f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project FAST_FLOAT * wsptr; 789f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project JSAMPROW outptr; 799f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project JSAMPLE *range_limit = IDCT_range_limit(cinfo); 809f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project int ctr; 819f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project FAST_FLOAT workspace[DCTSIZE2]; /* buffers data between passes */ 829f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project SHIFT_TEMPS 839f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 849f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Pass 1: process columns from input, store into work array. */ 859f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 869f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project inptr = coef_block; 879f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project quantptr = (FLOAT_MULT_TYPE *) compptr->dct_table; 889f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project wsptr = workspace; 899f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project for (ctr = DCTSIZE; ctr > 0; ctr--) { 909f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Due to quantization, we will usually find that many of the input 919f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * coefficients are zero, especially the AC terms. We can exploit this 929f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * by short-circuiting the IDCT calculation for any column in which all 939f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * the AC terms are zero. In that case each output is equal to the 949f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * DC coefficient (with scale factor as needed). 959f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * With typical images and quantization tables, half or more of the 969f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * column DCT calculations can be simplified this way. 979f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 989f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 999f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (inptr[DCTSIZE*1] == 0 && inptr[DCTSIZE*2] == 0 && 1009f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project inptr[DCTSIZE*3] == 0 && inptr[DCTSIZE*4] == 0 && 1019f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project inptr[DCTSIZE*5] == 0 && inptr[DCTSIZE*6] == 0 && 1029f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project inptr[DCTSIZE*7] == 0) { 1039f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* AC terms all zero */ 1049f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project FAST_FLOAT dcval = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]); 1059f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1069f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project wsptr[DCTSIZE*0] = dcval; 1079f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project wsptr[DCTSIZE*1] = dcval; 1089f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project wsptr[DCTSIZE*2] = dcval; 1099f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project wsptr[DCTSIZE*3] = dcval; 1109f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project wsptr[DCTSIZE*4] = dcval; 1119f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project wsptr[DCTSIZE*5] = dcval; 1129f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project wsptr[DCTSIZE*6] = dcval; 1139f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project wsptr[DCTSIZE*7] = dcval; 1149f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1159f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project inptr++; /* advance pointers to next column */ 1169f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project quantptr++; 1179f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project wsptr++; 1189f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project continue; 1199f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 1209f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1219f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Even part */ 1229f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1239f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp0 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]); 1249f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp1 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]); 1259f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp2 = DEQUANTIZE(inptr[DCTSIZE*4], quantptr[DCTSIZE*4]); 1269f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp3 = DEQUANTIZE(inptr[DCTSIZE*6], quantptr[DCTSIZE*6]); 1279f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1289f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp10 = tmp0 + tmp2; /* phase 3 */ 1299f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp11 = tmp0 - tmp2; 1309f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1319f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp13 = tmp1 + tmp3; /* phases 5-3 */ 1329f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp12 = (tmp1 - tmp3) * ((FAST_FLOAT) 1.414213562) - tmp13; /* 2*c4 */ 1339f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1349f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp0 = tmp10 + tmp13; /* phase 2 */ 1359f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp3 = tmp10 - tmp13; 1369f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp1 = tmp11 + tmp12; 1379f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp2 = tmp11 - tmp12; 1389f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1399f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Odd part */ 1409f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1419f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp4 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]); 1429f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp5 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]); 1439f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp6 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5]); 1449f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp7 = DEQUANTIZE(inptr[DCTSIZE*7], quantptr[DCTSIZE*7]); 1459f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1469f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project z13 = tmp6 + tmp5; /* phase 6 */ 1479f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project z10 = tmp6 - tmp5; 1489f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project z11 = tmp4 + tmp7; 1499f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project z12 = tmp4 - tmp7; 1509f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1519f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp7 = z11 + z13; /* phase 5 */ 1529f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp11 = (z11 - z13) * ((FAST_FLOAT) 1.414213562); /* 2*c4 */ 1539f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1549f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project z5 = (z10 + z12) * ((FAST_FLOAT) 1.847759065); /* 2*c2 */ 1559f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp10 = ((FAST_FLOAT) 1.082392200) * z12 - z5; /* 2*(c2-c6) */ 1569f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp12 = ((FAST_FLOAT) -2.613125930) * z10 + z5; /* -2*(c2+c6) */ 1579f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1589f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp6 = tmp12 - tmp7; /* phase 2 */ 1599f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp5 = tmp11 - tmp6; 1609f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp4 = tmp10 + tmp5; 1619f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1629f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project wsptr[DCTSIZE*0] = tmp0 + tmp7; 1639f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project wsptr[DCTSIZE*7] = tmp0 - tmp7; 1649f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project wsptr[DCTSIZE*1] = tmp1 + tmp6; 1659f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project wsptr[DCTSIZE*6] = tmp1 - tmp6; 1669f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project wsptr[DCTSIZE*2] = tmp2 + tmp5; 1679f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project wsptr[DCTSIZE*5] = tmp2 - tmp5; 1689f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project wsptr[DCTSIZE*4] = tmp3 + tmp4; 1699f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project wsptr[DCTSIZE*3] = tmp3 - tmp4; 1709f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1719f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project inptr++; /* advance pointers to next column */ 1729f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project quantptr++; 1739f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project wsptr++; 1749f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 1759f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1769f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Pass 2: process rows from work array, store into output array. */ 1779f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Note that we must descale the results by a factor of 8 == 2**3. */ 1789f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1799f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project wsptr = workspace; 1809f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project for (ctr = 0; ctr < DCTSIZE; ctr++) { 1819f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project outptr = output_buf[ctr] + output_col; 1829f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Rows of zeroes can be exploited in the same way as we did with columns. 1839f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * However, the column calculation has created many nonzero AC terms, so 1849f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * the simplification applies less often (typically 5% to 10% of the time). 1859f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * And testing floats for zero is relatively expensive, so we don't bother. 1869f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 1879f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1889f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Even part */ 1899f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1909f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp10 = wsptr[0] + wsptr[4]; 1919f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp11 = wsptr[0] - wsptr[4]; 1929f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1939f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp13 = wsptr[2] + wsptr[6]; 1949f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp12 = (wsptr[2] - wsptr[6]) * ((FAST_FLOAT) 1.414213562) - tmp13; 1959f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1969f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp0 = tmp10 + tmp13; 1979f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp3 = tmp10 - tmp13; 1989f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp1 = tmp11 + tmp12; 1999f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp2 = tmp11 - tmp12; 2009f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 2019f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Odd part */ 2029f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 2039f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project z13 = wsptr[5] + wsptr[3]; 2049f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project z10 = wsptr[5] - wsptr[3]; 2059f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project z11 = wsptr[1] + wsptr[7]; 2069f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project z12 = wsptr[1] - wsptr[7]; 2079f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 2089f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp7 = z11 + z13; 2099f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp11 = (z11 - z13) * ((FAST_FLOAT) 1.414213562); 2109f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 2119f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project z5 = (z10 + z12) * ((FAST_FLOAT) 1.847759065); /* 2*c2 */ 2129f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp10 = ((FAST_FLOAT) 1.082392200) * z12 - z5; /* 2*(c2-c6) */ 2139f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp12 = ((FAST_FLOAT) -2.613125930) * z10 + z5; /* -2*(c2+c6) */ 2149f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 2159f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp6 = tmp12 - tmp7; 2169f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp5 = tmp11 - tmp6; 2179f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project tmp4 = tmp10 + tmp5; 2189f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 2199f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Final output stage: scale down by a factor of 8 and range-limit */ 2209f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 2219f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project outptr[0] = range_limit[(int) DESCALE((INT32) (tmp0 + tmp7), 3) 2229f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project & RANGE_MASK]; 2239f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project outptr[7] = range_limit[(int) DESCALE((INT32) (tmp0 - tmp7), 3) 2249f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project & RANGE_MASK]; 2259f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project outptr[1] = range_limit[(int) DESCALE((INT32) (tmp1 + tmp6), 3) 2269f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project & RANGE_MASK]; 2279f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project outptr[6] = range_limit[(int) DESCALE((INT32) (tmp1 - tmp6), 3) 2289f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project & RANGE_MASK]; 2299f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project outptr[2] = range_limit[(int) DESCALE((INT32) (tmp2 + tmp5), 3) 2309f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project & RANGE_MASK]; 2319f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project outptr[5] = range_limit[(int) DESCALE((INT32) (tmp2 - tmp5), 3) 2329f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project & RANGE_MASK]; 2339f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project outptr[4] = range_limit[(int) DESCALE((INT32) (tmp3 + tmp4), 3) 2349f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project & RANGE_MASK]; 2359f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project outptr[3] = range_limit[(int) DESCALE((INT32) (tmp3 - tmp4), 3) 2369f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project & RANGE_MASK]; 2379f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 2389f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project wsptr += DCTSIZE; /* advance pointer to next row */ 2399f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 2409f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project} 2419f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 2429f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#endif /* DCT_FLOAT_SUPPORTED */ 243