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+/*
+ * jrevdct.c
+ *
+ * Copyright (C) 1991, 1992, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains the basic inverse-DCT transformation subroutine.
+ *
+ * This implementation is based on an algorithm described in
+ * C. Loeffler, A. Ligtenberg and G. Moschytz, "Practical Fast 1-D DCT
+ * Algorithms with 11 Multiplications", Proc. Int'l. Conf. on Acoustics,
+ * Speech, and Signal Processing 1989 (ICASSP '89), pp. 988-991.
+ * The primary algorithm described there uses 11 multiplies and 29 adds.
+ * We use their alternate method with 12 multiplies and 32 adds.
+ * The advantage of this method is that no data path contains more than one
+ * multiplication; this allows a very simple and accurate implementation in
+ * scaled fixed-point arithmetic, with a minimal number of shifts.
+ *
+ * I've made lots of modifications to attempt to take advantage of the
+ * sparse nature of the DCT matrices we're getting. Although the logic
+ * is cumbersome, it's straightforward and the resulting code is much
+ * faster.
+ *
+ * A better way to do this would be to pass in the DCT block as a sparse
+ * matrix, perhaps with the difference cases encoded.
+ */
+
+typedef int INT32;
+
+/* Definition of Contant integer scale factor. */
+#define CONST_BITS 13
+
+/* Misc DCT definitions */
+#define DCTSIZE 8 /* The basic DCT block is 8x8 samples */
+#define DCTSIZE2 64 /* DCTSIZE squared; # of elements in a block */
+
+#define GLOBAL /* a function referenced thru EXTERNs */
+
+typedef int DCTELEM;
+typedef DCTELEM DCTBLOCK[DCTSIZE2];
+
+void j_rev_dct (DCTELEM *data);
+
+
+#define GLOBAL /* a function referenced thru EXTERNs */
+#define ORIG_DCT 1
+
+/* We assume that right shift corresponds to signed division by 2 with
+ * rounding towards minus infinity. This is correct for typical "arithmetic
+ * shift" instructions that shift in copies of the sign bit. But some
+ * C compilers implement >> with an unsigned shift. For these machines you
+ * must define RIGHT_SHIFT_IS_UNSIGNED.
+ * RIGHT_SHIFT provides a proper signed right shift of an INT32 quantity.
+ * It is only applied with constant shift counts. SHIFT_TEMPS must be
+ * included in the variables of any routine using RIGHT_SHIFT.
+ */
+
+#ifdef RIGHT_SHIFT_IS_UNSIGNED
+#define SHIFT_TEMPS INT32 shift_temp;
+#define RIGHT_SHIFT(x,shft) \
+ ((shift_temp = (x)) < 0 ? \
+ (shift_temp >> (shft)) | ((~((INT32) 0)) << (32-(shft))) : \
+ (shift_temp >> (shft)))
+#else
+#define SHIFT_TEMPS
+#define RIGHT_SHIFT(x,shft) ((x) >> (shft))
+#endif
+
+/*
+ * This routine is specialized to the case DCTSIZE = 8.
+ */
+
+#if DCTSIZE != 8
+ Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */
+#endif
+
+
+/*
+ * A 2-D IDCT can be done by 1-D IDCT on each row followed by 1-D IDCT
+ * on each column. Direct algorithms are also available, but they are
+ * much more complex and seem not to be any faster when reduced to code.
+ *
+ * The poop on this scaling stuff is as follows:
+ *
+ * Each 1-D IDCT step produces outputs which are a factor of sqrt(N)
+ * larger than the true IDCT outputs. The final outputs are therefore
+ * a factor of N larger than desired; since N=8 this can be cured by
+ * a simple right shift at the end of the algorithm. The advantage of
+ * this arrangement is that we save two multiplications per 1-D IDCT,
+ * because the y0 and y4 inputs need not be divided by sqrt(N).
+ *
+ * We have to do addition and subtraction of the integer inputs, which
+ * is no problem, and multiplication by fractional constants, which is
+ * a problem to do in integer arithmetic. We multiply all the constants
+ * by CONST_SCALE and convert them to integer constants (thus retaining
+ * CONST_BITS bits of precision in the constants). After doing a
+ * multiplication we have to divide the product by CONST_SCALE, with proper
+ * rounding, to produce the correct output. This division can be done
+ * cheaply as a right shift of CONST_BITS bits. We postpone shifting
+ * as long as possible so that partial sums can be added together with
+ * full fractional precision.
+ *
+ * The outputs of the first pass are scaled up by PASS1_BITS bits so that
+ * they are represented to better-than-integral precision. These outputs
+ * require BITS_IN_JSAMPLE + PASS1_BITS + 3 bits; this fits in a 16-bit word
+ * with the recommended scaling. (To scale up 12-bit sample data further, an
+ * intermediate INT32 array would be needed.)
+ *
+ * To avoid overflow of the 32-bit intermediate results in pass 2, we must
+ * have BITS_IN_JSAMPLE + CONST_BITS + PASS1_BITS <= 26. Error analysis
+ * shows that the values given below are the most effective.
+ */
+
+#ifdef EIGHT_BIT_SAMPLES
+#define PASS1_BITS 2
+#else
+#define PASS1_BITS 1 /* lose a little precision to avoid overflow */
+#endif
+
+#define ONE ((INT32) 1)
+
+#define CONST_SCALE (ONE << CONST_BITS)
+
+/* Convert a positive real constant to an integer scaled by CONST_SCALE.
+ * IMPORTANT: if your compiler doesn't do this arithmetic at compile time,
+ * you will pay a significant penalty in run time. In that case, figure
+ * the correct integer constant values and insert them by hand.
+ */
+
+#define FIX(x) ((INT32) ((x) * CONST_SCALE + 0.5))
+
+/* Descale and correctly round an INT32 value that's scaled by N bits.
+ * We assume RIGHT_SHIFT rounds towards minus infinity, so adding
+ * the fudge factor is correct for either sign of X.
+ */
+
+#define DESCALE(x,n) RIGHT_SHIFT((x) + (ONE << ((n)-1)), n)
+#define SCALE(x,n) ((INT32)(x) << n)
+
+/* Multiply an INT32 variable by an INT32 constant to yield an INT32 result.
+ * For 8-bit samples with the recommended scaling, all the variable
+ * and constant values involved are no more than 16 bits wide, so a
+ * 16x16->32 bit multiply can be used instead of a full 32x32 multiply;
+ * this provides a useful speedup on many machines.
+ * There is no way to specify a 16x16->32 multiply in portable C, but
+ * some C compilers will do the right thing if you provide the correct
+ * combination of casts.
+ * NB: for 12-bit samples, a full 32-bit multiplication will be needed.
+ */
+
+#ifdef EIGHT_BIT_SAMPLES
+#ifdef SHORTxSHORT_32 /* may work if 'int' is 32 bits */
+#define MULTIPLY(var,const) (((INT16) (var)) * ((INT16) (const)))
+#endif
+#ifdef SHORTxLCONST_32 /* known to work with Microsoft C 6.0 */
+#define MULTIPLY(var,const) (((INT16) (var)) * ((INT32) (const)))
+#endif
+#endif
+
+#if 0
+/* force a multiplication for x86 where a multiply is fast). We
+ force the non constant operand to be in a register because
+ otherwise it may be a 16 bit memory reference, which is not allowed
+ by imull */
+#define MULTIPLY(a,b) \
+({\
+ int res;\
+ asm("imull %2,%1,%0" : "=r" (res) : "r" ((int)(a)), "i" (b));\
+ res;\
+})
+#endif
+
+#ifndef MULTIPLY /* default definition */
+#define MULTIPLY(var,const) ((var) * (const))
+#endif
+
+
+#ifndef ORIG_DCT
+
+#undef SSMUL
+#define SSMUL(var1,var2) ((INT16)(var1) * (INT32)(INT16)(var2))
+
+/* Precomputed idct value arrays. */
+
+STATIC DCTELEM PreIDCT[64][64];
+
+/* Pre compute singleton coefficient IDCT values. */
+void init_pre_idct() {
+ int i;
+
+ for (i = 0; i < 64; i++) {
+ memset ((char *) PreIDCT[i], 0, 64 * sizeof(DCTELEM));
+ PreIDCT[i][i] = 2048;
+ j_rev_dct (PreIDCT[i]);
+ }
+}
+
+/*
+ * Perform the inverse DCT on one block of coefficients.
+ */
+
+void j_rev_dct_sparse (data, pos)
+ DCTBLOCK data;
+ int pos;
+{
+ register DCTELEM *dataptr;
+ short int val;
+ DCTELEM *ndataptr;
+ int coeff, rr;
+
+ /* If DC Coefficient. */
+
+ if (pos == 0) {
+ register INT32 *dp;
+ register INT32 v;
+
+ dp = (INT32*)data;
+ v = *data;
+ /* Compute 32 bit value to assign.
+ * This speeds things up a bit */
+ if (v < 0)
+ val = (short)((v - 3) >> 3);
+ else
+ val = (short)((v + 4) >> 3);
+ v = val | ((INT32)val << 16);
+ dp[0] = v; dp[1] = v; dp[2] = v; dp[3] = v;
+ dp[4] = v; dp[5] = v; dp[6] = v; dp[7] = v;
+ dp[8] = v; dp[9] = v; dp[10] = v; dp[11] = v;
+ dp[12] = v; dp[13] = v; dp[14] = v; dp[15] = v;
+ dp[16] = v; dp[17] = v; dp[18] = v; dp[19] = v;
+ dp[20] = v; dp[21] = v; dp[22] = v; dp[23] = v;
+ dp[24] = v; dp[25] = v; dp[26] = v; dp[27] = v;
+ dp[28] = v; dp[29] = v; dp[30] = v; dp[31] = v;
+ return;
+ }
+
+ /* Some other coefficient. */
+ dataptr = (DCTELEM *)data;
+ coeff = dataptr[pos];
+ ndataptr = PreIDCT[pos];
+
+ for (rr = 0; rr < 4; rr++) {
+ dataptr[0] = (DCTELEM)(SSMUL (ndataptr[0] , coeff) >> (CONST_BITS-2));
+ dataptr[1] = (DCTELEM)(SSMUL (ndataptr[1] , coeff) >> (CONST_BITS-2));
+ dataptr[2] = (DCTELEM)(SSMUL (ndataptr[2] , coeff) >> (CONST_BITS-2));
+ dataptr[3] = (DCTELEM)(SSMUL (ndataptr[3] , coeff) >> (CONST_BITS-2));
+ dataptr[4] = (DCTELEM)(SSMUL (ndataptr[4] , coeff) >> (CONST_BITS-2));
+ dataptr[5] = (DCTELEM)(SSMUL (ndataptr[5] , coeff) >> (CONST_BITS-2));
+ dataptr[6] = (DCTELEM)(SSMUL (ndataptr[6] , coeff) >> (CONST_BITS-2));
+ dataptr[7] = (DCTELEM)(SSMUL (ndataptr[7] , coeff) >> (CONST_BITS-2));
+ dataptr[8] = (DCTELEM)(SSMUL (ndataptr[8] , coeff) >> (CONST_BITS-2));
+ dataptr[9] = (DCTELEM)(SSMUL (ndataptr[9] , coeff) >> (CONST_BITS-2));
+ dataptr[10] = (DCTELEM)(SSMUL (ndataptr[10], coeff) >> (CONST_BITS-2));
+ dataptr[11] = (DCTELEM)(SSMUL (ndataptr[11], coeff) >> (CONST_BITS-2));
+ dataptr[12] = (DCTELEM)(SSMUL (ndataptr[12], coeff) >> (CONST_BITS-2));
+ dataptr[13] = (DCTELEM)(SSMUL (ndataptr[13], coeff) >> (CONST_BITS-2));
+ dataptr[14] = (DCTELEM)(SSMUL (ndataptr[14], coeff) >> (CONST_BITS-2));
+ dataptr[15] = (DCTELEM)(SSMUL (ndataptr[15], coeff) >> (CONST_BITS-2));
+ dataptr += 16;
+ ndataptr += 16;
+ }
+}
+
+
+void j_rev_dct (data)
+ DCTBLOCK data;
+{
+ INT32 tmp0, tmp1, tmp2, tmp3;
+ INT32 tmp10, tmp11, tmp12, tmp13;
+ INT32 z1, z2, z3, z4, z5;
+ int d0, d1, d2, d3, d4, d5, d6, d7;
+ register DCTELEM *dataptr;
+ int rowctr;
+ SHIFT_TEMPS;
+
+ /* Pass 1: process rows. */
+ /* Note results are scaled up by sqrt(8) compared to a true IDCT; */
+ /* furthermore, we scale the results by 2**PASS1_BITS. */
+
+ dataptr = data;
+
+ for (rowctr = DCTSIZE - 1; rowctr >= 0; rowctr--) {
+ /* Due to quantization, we will usually find that many of the input
+ * coefficients are zero, especially the AC terms. We can exploit this
+ * by short-circuiting the IDCT calculation for any row in which all
+ * the AC terms are zero. In that case each output is equal to the
+ * DC coefficient (with scale factor as needed).
+ * With typical images and quantization tables, half or more of the
+ * row DCT calculations can be simplified this way.
+ */
+
+ register INT32 *idataptr = (INT32*)dataptr;
+ d0 = dataptr[0];
+ d1 = dataptr[1];
+ if ((d1 == 0) && (idataptr[1] | idataptr[2] | idataptr[3]) == 0) {
+ /* AC terms all zero */
+ if (d0) {
+ /* Compute a 32 bit value to assign. */
+ DCTELEM dcval = (DCTELEM) (d0 << PASS1_BITS);
+ register INT32 v = (dcval & 0xffff) |
+ (((INT32)dcval << 16) & 0xffff0000L);
+
+ idataptr[0] = v;
+ idataptr[1] = v;
+ idataptr[2] = v;
+ idataptr[3] = v;
+ }
+
+ dataptr += DCTSIZE; /* advance pointer to next row */
+ continue;
+ }
+ d2 = dataptr[2];
+ d3 = dataptr[3];
+ d4 = dataptr[4];
+ d5 = dataptr[5];
+ d6 = dataptr[6];
+ d7 = dataptr[7];
+
+ /* Even part: reverse the even part of the forward DCT. */
+ /* The rotator is sqrt(2)*c(-6). */
+ if (d6) {
+ if (d4) {
+ if (d2) {
+ if (d0) {
+ /* d0 != 0, d2 != 0, d4 != 0, d6 != 0 */
+ z1 = MULTIPLY(d2 + d6, FIX(0.541196100));
+ tmp2 = z1 + MULTIPLY(d6, - FIX(1.847759065));
+ tmp3 = z1 + MULTIPLY(d2, FIX(0.765366865));
+
+ tmp0 = SCALE (d0 + d4, CONST_BITS);
+ tmp1 = SCALE (d0 - d4, CONST_BITS);
+
+ tmp10 = tmp0 + tmp3;
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp1 + tmp2;
+ tmp12 = tmp1 - tmp2;
+ } else {
+ /* d0 == 0, d2 != 0, d4 != 0, d6 != 0 */
+ z1 = MULTIPLY(d2 + d6, FIX(0.541196100));
+ tmp2 = z1 + MULTIPLY(d6, - FIX(1.847759065));
+ tmp3 = z1 + MULTIPLY(d2, FIX(0.765366865));
+
+ tmp0 = SCALE (d4, CONST_BITS);
+
+ tmp10 = tmp0 + tmp3;
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp2 - tmp0;
+ tmp12 = -(tmp0 + tmp2);
+ }
+ } else {
+ if (d0) {
+ /* d0 != 0, d2 == 0, d4 != 0, d6 != 0 */
+ tmp2 = MULTIPLY(d6, - FIX(1.306562965));
+ tmp3 = MULTIPLY(d6, FIX(0.541196100));
+
+ tmp0 = SCALE (d0 + d4, CONST_BITS);
+ tmp1 = SCALE (d0 - d4, CONST_BITS);
+
+ tmp10 = tmp0 + tmp3;
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp1 + tmp2;
+ tmp12 = tmp1 - tmp2;
+ } else {
+ /* d0 == 0, d2 == 0, d4 != 0, d6 != 0 */
+ tmp2 = MULTIPLY(d6, -FIX(1.306562965));
+ tmp3 = MULTIPLY(d6, FIX(0.541196100));
+
+ tmp0 = SCALE (d4, CONST_BITS);
+
+ tmp10 = tmp0 + tmp3;
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp2 - tmp0;
+ tmp12 = -(tmp0 + tmp2);
+ }
+ }
+ } else {
+ if (d2) {
+ if (d0) {
+ /* d0 != 0, d2 != 0, d4 == 0, d6 != 0 */
+ z1 = MULTIPLY(d2 + d6, FIX(0.541196100));
+ tmp2 = z1 + MULTIPLY(d6, - FIX(1.847759065));
+ tmp3 = z1 + MULTIPLY(d2, FIX(0.765366865));
+
+ tmp0 = SCALE (d0, CONST_BITS);
+
+ tmp10 = tmp0 + tmp3;
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp0 + tmp2;
+ tmp12 = tmp0 - tmp2;
+ } else {
+ /* d0 == 0, d2 != 0, d4 == 0, d6 != 0 */
+ z1 = MULTIPLY(d2 + d6, FIX(0.541196100));
+ tmp2 = z1 + MULTIPLY(d6, - FIX(1.847759065));
+ tmp3 = z1 + MULTIPLY(d2, FIX(0.765366865));
+
+ tmp10 = tmp3;
+ tmp13 = -tmp3;
+ tmp11 = tmp2;
+ tmp12 = -tmp2;
+ }
+ } else {
+ if (d0) {
+ /* d0 != 0, d2 == 0, d4 == 0, d6 != 0 */
+ tmp2 = MULTIPLY(d6, - FIX(1.306562965));
+ tmp3 = MULTIPLY(d6, FIX(0.541196100));
+
+ tmp0 = SCALE (d0, CONST_BITS);
+
+ tmp10 = tmp0 + tmp3;
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp0 + tmp2;
+ tmp12 = tmp0 - tmp2;
+ } else {
+ /* d0 == 0, d2 == 0, d4 == 0, d6 != 0 */
+ tmp2 = MULTIPLY(d6, - FIX(1.306562965));
+ tmp3 = MULTIPLY(d6, FIX(0.541196100));
+
+ tmp10 = tmp3;
+ tmp13 = -tmp3;
+ tmp11 = tmp2;
+ tmp12 = -tmp2;
+ }
+ }
+ }
+ } else {
+ if (d4) {
+ if (d2) {
+ if (d0) {
+ /* d0 != 0, d2 != 0, d4 != 0, d6 == 0 */
+ tmp2 = MULTIPLY(d2, FIX(0.541196100));
+ tmp3 = MULTIPLY(d2, FIX(1.306562965));
+
+ tmp0 = SCALE (d0 + d4, CONST_BITS);
+ tmp1 = SCALE (d0 - d4, CONST_BITS);
+
+ tmp10 = tmp0 + tmp3;
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp1 + tmp2;
+ tmp12 = tmp1 - tmp2;
+ } else {
+ /* d0 == 0, d2 != 0, d4 != 0, d6 == 0 */
+ tmp2 = MULTIPLY(d2, FIX(0.541196100));
+ tmp3 = MULTIPLY(d2, FIX(1.306562965));
+
+ tmp0 = SCALE (d4, CONST_BITS);
+
+ tmp10 = tmp0 + tmp3;
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp2 - tmp0;
+ tmp12 = -(tmp0 + tmp2);
+ }
+ } else {
+ if (d0) {
+ /* d0 != 0, d2 == 0, d4 != 0, d6 == 0 */
+ tmp10 = tmp13 = SCALE (d0 + d4, CONST_BITS);
+ tmp11 = tmp12 = SCALE (d0 - d4, CONST_BITS);
+ } else {
+ /* d0 == 0, d2 == 0, d4 != 0, d6 == 0 */
+ tmp10 = tmp13 = SCALE (d4, CONST_BITS);
+ tmp11 = tmp12 = -tmp10;
+ }
+ }
+ } else {
+ if (d2) {
+ if (d0) {
+ /* d0 != 0, d2 != 0, d4 == 0, d6 == 0 */
+ tmp2 = MULTIPLY(d2, FIX(0.541196100));
+ tmp3 = MULTIPLY(d2, FIX(1.306562965));
+
+ tmp0 = SCALE (d0, CONST_BITS);
+
+ tmp10 = tmp0 + tmp3;
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp0 + tmp2;
+ tmp12 = tmp0 - tmp2;
+ } else {
+ /* d0 == 0, d2 != 0, d4 == 0, d6 == 0 */
+ tmp2 = MULTIPLY(d2, FIX(0.541196100));
+ tmp3 = MULTIPLY(d2, FIX(1.306562965));
+
+ tmp10 = tmp3;
+ tmp13 = -tmp3;
+ tmp11 = tmp2;
+ tmp12 = -tmp2;
+ }
+ } else {
+ if (d0) {
+ /* d0 != 0, d2 == 0, d4 == 0, d6 == 0 */
+ tmp10 = tmp13 = tmp11 = tmp12 = SCALE (d0, CONST_BITS);
+ } else {
+ /* d0 == 0, d2 == 0, d4 == 0, d6 == 0 */
+ tmp10 = tmp13 = tmp11 = tmp12 = 0;
+ }
+ }
+ }
+ }
+
+
+ /* Odd part per figure 8; the matrix is unitary and hence its
+ * transpose is its inverse. i0..i3 are y7,y5,y3,y1 respectively.
+ */
+
+ if (d7) {
+ if (d5) {
+ if (d3) {
+ if (d1) {
+ /* d1 != 0, d3 != 0, d5 != 0, d7 != 0 */
+ z1 = d7 + d1;
+ z2 = d5 + d3;
+ z3 = d7 + d3;
+ z4 = d5 + d1;
+ z5 = MULTIPLY(z3 + z4, FIX(1.175875602));
+
+ tmp0 = MULTIPLY(d7, FIX(0.298631336));
+ tmp1 = MULTIPLY(d5, FIX(2.053119869));
+ tmp2 = MULTIPLY(d3, FIX(3.072711026));
+ tmp3 = MULTIPLY(d1, FIX(1.501321110));
+ z1 = MULTIPLY(z1, - FIX(0.899976223));
+ z2 = MULTIPLY(z2, - FIX(2.562915447));
+ z3 = MULTIPLY(z3, - FIX(1.961570560));
+ z4 = MULTIPLY(z4, - FIX(0.390180644));
+
+ z3 += z5;
+ z4 += z5;
+
+ tmp0 += z1 + z3;
+ tmp1 += z2 + z4;
+ tmp2 += z2 + z3;
+ tmp3 += z1 + z4;
+ } else {
+ /* d1 == 0, d3 != 0, d5 != 0, d7 != 0 */
+ z1 = d7;
+ z2 = d5 + d3;
+ z3 = d7 + d3;
+ z5 = MULTIPLY(z3 + d5, FIX(1.175875602));
+
+ tmp0 = MULTIPLY(d7, FIX(0.298631336));
+ tmp1 = MULTIPLY(d5, FIX(2.053119869));
+ tmp2 = MULTIPLY(d3, FIX(3.072711026));
+ z1 = MULTIPLY(d7, - FIX(0.899976223));
+ z2 = MULTIPLY(z2, - FIX(2.562915447));
+ z3 = MULTIPLY(z3, - FIX(1.961570560));
+ z4 = MULTIPLY(d5, - FIX(0.390180644));
+
+ z3 += z5;
+ z4 += z5;
+
+ tmp0 += z1 + z3;
+ tmp1 += z2 + z4;
+ tmp2 += z2 + z3;
+ tmp3 = z1 + z4;
+ }
+ } else {
+ if (d1) {
+ /* d1 != 0, d3 == 0, d5 != 0, d7 != 0 */
+ z1 = d7 + d1;
+ z2 = d5;
+ z3 = d7;
+ z4 = d5 + d1;
+ z5 = MULTIPLY(z3 + z4, FIX(1.175875602));
+
+ tmp0 = MULTIPLY(d7, FIX(0.298631336));
+ tmp1 = MULTIPLY(d5, FIX(2.053119869));
+ tmp3 = MULTIPLY(d1, FIX(1.501321110));
+ z1 = MULTIPLY(z1, - FIX(0.899976223));
+ z2 = MULTIPLY(d5, - FIX(2.562915447));
+ z3 = MULTIPLY(d7, - FIX(1.961570560));
+ z4 = MULTIPLY(z4, - FIX(0.390180644));
+
+ z3 += z5;
+ z4 += z5;
+
+ tmp0 += z1 + z3;
+ tmp1 += z2 + z4;
+ tmp2 = z2 + z3;
+ tmp3 += z1 + z4;
+ } else {
+ /* d1 == 0, d3 == 0, d5 != 0, d7 != 0 */
+ tmp0 = MULTIPLY(d7, - FIX(0.601344887));
+ z1 = MULTIPLY(d7, - FIX(0.899976223));
+ z3 = MULTIPLY(d7, - FIX(1.961570560));
+ tmp1 = MULTIPLY(d5, - FIX(0.509795578));
+ z2 = MULTIPLY(d5, - FIX(2.562915447));
+ z4 = MULTIPLY(d5, - FIX(0.390180644));
+ z5 = MULTIPLY(d5 + d7, FIX(1.175875602));
+
+ z3 += z5;
+ z4 += z5;
+
+ tmp0 += z3;
+ tmp1 += z4;
+ tmp2 = z2 + z3;
+ tmp3 = z1 + z4;
+ }
+ }
+ } else {
+ if (d3) {
+ if (d1) {
+ /* d1 != 0, d3 != 0, d5 == 0, d7 != 0 */
+ z1 = d7 + d1;
+ z3 = d7 + d3;
+ z5 = MULTIPLY(z3 + d1, FIX(1.175875602));
+
+ tmp0 = MULTIPLY(d7, FIX(0.298631336));
+ tmp2 = MULTIPLY(d3, FIX(3.072711026));
+ tmp3 = MULTIPLY(d1, FIX(1.501321110));
+ z1 = MULTIPLY(z1, - FIX(0.899976223));
+ z2 = MULTIPLY(d3, - FIX(2.562915447));
+ z3 = MULTIPLY(z3, - FIX(1.961570560));
+ z4 = MULTIPLY(d1, - FIX(0.390180644));
+
+ z3 += z5;
+ z4 += z5;
+
+ tmp0 += z1 + z3;
+ tmp1 = z2 + z4;
+ tmp2 += z2 + z3;
+ tmp3 += z1 + z4;
+ } else {
+ /* d1 == 0, d3 != 0, d5 == 0, d7 != 0 */
+ z3 = d7 + d3;
+
+ tmp0 = MULTIPLY(d7, - FIX(0.601344887));
+ z1 = MULTIPLY(d7, - FIX(0.899976223));
+ tmp2 = MULTIPLY(d3, FIX(0.509795579));
+ z2 = MULTIPLY(d3, - FIX(2.562915447));
+ z5 = MULTIPLY(z3, FIX(1.175875602));
+ z3 = MULTIPLY(z3, - FIX(0.785694958));
+
+ tmp0 += z3;
+ tmp1 = z2 + z5;
+ tmp2 += z3;
+ tmp3 = z1 + z5;
+ }
+ } else {
+ if (d1) {
+ /* d1 != 0, d3 == 0, d5 == 0, d7 != 0 */
+ z1 = d7 + d1;
+ z5 = MULTIPLY(z1, FIX(1.175875602));
+
+ z1 = MULTIPLY(z1, FIX(0.275899379));
+ z3 = MULTIPLY(d7, - FIX(1.961570560));
+ tmp0 = MULTIPLY(d7, - FIX(1.662939224));
+ z4 = MULTIPLY(d1, - FIX(0.390180644));
+ tmp3 = MULTIPLY(d1, FIX(1.111140466));
+
+ tmp0 += z1;
+ tmp1 = z4 + z5;
+ tmp2 = z3 + z5;
+ tmp3 += z1;
+ } else {
+ /* d1 == 0, d3 == 0, d5 == 0, d7 != 0 */
+ tmp0 = MULTIPLY(d7, - FIX(1.387039845));
+ tmp1 = MULTIPLY(d7, FIX(1.175875602));
+ tmp2 = MULTIPLY(d7, - FIX(0.785694958));
+ tmp3 = MULTIPLY(d7, FIX(0.275899379));
+ }
+ }
+ }
+ } else {
+ if (d5) {
+ if (d3) {
+ if (d1) {
+ /* d1 != 0, d3 != 0, d5 != 0, d7 == 0 */
+ z2 = d5 + d3;
+ z4 = d5 + d1;
+ z5 = MULTIPLY(d3 + z4, FIX(1.175875602));
+
+ tmp1 = MULTIPLY(d5, FIX(2.053119869));
+ tmp2 = MULTIPLY(d3, FIX(3.072711026));
+ tmp3 = MULTIPLY(d1, FIX(1.501321110));
+ z1 = MULTIPLY(d1, - FIX(0.899976223));
+ z2 = MULTIPLY(z2, - FIX(2.562915447));
+ z3 = MULTIPLY(d3, - FIX(1.961570560));
+ z4 = MULTIPLY(z4, - FIX(0.390180644));
+
+ z3 += z5;
+ z4 += z5;
+
+ tmp0 = z1 + z3;
+ tmp1 += z2 + z4;
+ tmp2 += z2 + z3;
+ tmp3 += z1 + z4;
+ } else {
+ /* d1 == 0, d3 != 0, d5 != 0, d7 == 0 */
+ z2 = d5 + d3;
+
+ z5 = MULTIPLY(z2, FIX(1.175875602));
+ tmp1 = MULTIPLY(d5, FIX(1.662939225));
+ z4 = MULTIPLY(d5, - FIX(0.390180644));
+ z2 = MULTIPLY(z2, - FIX(1.387039845));
+ tmp2 = MULTIPLY(d3, FIX(1.111140466));
+ z3 = MULTIPLY(d3, - FIX(1.961570560));
+
+ tmp0 = z3 + z5;
+ tmp1 += z2;
+ tmp2 += z2;
+ tmp3 = z4 + z5;
+ }
+ } else {
+ if (d1) {
+ /* d1 != 0, d3 == 0, d5 != 0, d7 == 0 */
+ z4 = d5 + d1;
+
+ z5 = MULTIPLY(z4, FIX(1.175875602));
+ z1 = MULTIPLY(d1, - FIX(0.899976223));
+ tmp3 = MULTIPLY(d1, FIX(0.601344887));
+ tmp1 = MULTIPLY(d5, - FIX(0.509795578));
+ z2 = MULTIPLY(d5, - FIX(2.562915447));
+ z4 = MULTIPLY(z4, FIX(0.785694958));
+
+ tmp0 = z1 + z5;
+ tmp1 += z4;
+ tmp2 = z2 + z5;
+ tmp3 += z4;
+ } else {
+ /* d1 == 0, d3 == 0, d5 != 0, d7 == 0 */
+ tmp0 = MULTIPLY(d5, FIX(1.175875602));
+ tmp1 = MULTIPLY(d5, FIX(0.275899380));
+ tmp2 = MULTIPLY(d5, - FIX(1.387039845));
+ tmp3 = MULTIPLY(d5, FIX(0.785694958));
+ }
+ }
+ } else {
+ if (d3) {
+ if (d1) {
+ /* d1 != 0, d3 != 0, d5 == 0, d7 == 0 */
+ z5 = d1 + d3;
+ tmp3 = MULTIPLY(d1, FIX(0.211164243));
+ tmp2 = MULTIPLY(d3, - FIX(1.451774981));
+ z1 = MULTIPLY(d1, FIX(1.061594337));
+ z2 = MULTIPLY(d3, - FIX(2.172734803));
+ z4 = MULTIPLY(z5, FIX(0.785694958));
+ z5 = MULTIPLY(z5, FIX(1.175875602));
+
+ tmp0 = z1 - z4;
+ tmp1 = z2 + z4;
+ tmp2 += z5;
+ tmp3 += z5;
+ } else {
+ /* d1 == 0, d3 != 0, d5 == 0, d7 == 0 */
+ tmp0 = MULTIPLY(d3, - FIX(0.785694958));
+ tmp1 = MULTIPLY(d3, - FIX(1.387039845));
+ tmp2 = MULTIPLY(d3, - FIX(0.275899379));
+ tmp3 = MULTIPLY(d3, FIX(1.175875602));
+ }
+ } else {
+ if (d1) {
+ /* d1 != 0, d3 == 0, d5 == 0, d7 == 0 */
+ tmp0 = MULTIPLY(d1, FIX(0.275899379));
+ tmp1 = MULTIPLY(d1, FIX(0.785694958));
+ tmp2 = MULTIPLY(d1, FIX(1.175875602));
+ tmp3 = MULTIPLY(d1, FIX(1.387039845));
+ } else {
+ /* d1 == 0, d3 == 0, d5 == 0, d7 == 0 */
+ tmp0 = tmp1 = tmp2 = tmp3 = 0;
+ }
+ }
+ }
+ }
+
+ /* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
+
+ dataptr[0] = (DCTELEM) DESCALE(tmp10 + tmp3, CONST_BITS-PASS1_BITS);
+ dataptr[7] = (DCTELEM) DESCALE(tmp10 - tmp3, CONST_BITS-PASS1_BITS);
+ dataptr[1] = (DCTELEM) DESCALE(tmp11 + tmp2, CONST_BITS-PASS1_BITS);
+ dataptr[6] = (DCTELEM) DESCALE(tmp11 - tmp2, CONST_BITS-PASS1_BITS);
+ dataptr[2] = (DCTELEM) DESCALE(tmp12 + tmp1, CONST_BITS-PASS1_BITS);
+ dataptr[5] = (DCTELEM) DESCALE(tmp12 - tmp1, CONST_BITS-PASS1_BITS);
+ dataptr[3] = (DCTELEM) DESCALE(tmp13 + tmp0, CONST_BITS-PASS1_BITS);
+ dataptr[4] = (DCTELEM) DESCALE(tmp13 - tmp0, CONST_BITS-PASS1_BITS);
+
+ dataptr += DCTSIZE; /* advance pointer to next row */
+ }
+
+ /* Pass 2: process columns. */
+ /* Note that we must descale the results by a factor of 8 == 2**3, */
+ /* and also undo the PASS1_BITS scaling. */
+
+ dataptr = data;
+ for (rowctr = DCTSIZE-1; rowctr >= 0; rowctr--) {
+ /* Columns of zeroes can be exploited in the same way as we did with rows.
+ * However, the row calculation has created many nonzero AC terms, so the
+ * simplification applies less often (typically 5% to 10% of the time).
+ * On machines with very fast multiplication, it's possible that the
+ * test takes more time than it's worth. In that case this section
+ * may be commented out.
+ */
+
+ d0 = dataptr[DCTSIZE*0];
+ d1 = dataptr[DCTSIZE*1];
+ d2 = dataptr[DCTSIZE*2];
+ d3 = dataptr[DCTSIZE*3];
+ d4 = dataptr[DCTSIZE*4];
+ d5 = dataptr[DCTSIZE*5];
+ d6 = dataptr[DCTSIZE*6];
+ d7 = dataptr[DCTSIZE*7];
+
+ /* Even part: reverse the even part of the forward DCT. */
+ /* The rotator is sqrt(2)*c(-6). */
+ if (d6) {
+ if (d4) {
+ if (d2) {
+ if (d0) {
+ /* d0 != 0, d2 != 0, d4 != 0, d6 != 0 */
+ z1 = MULTIPLY(d2 + d6, FIX(0.541196100));
+ tmp2 = z1 + MULTIPLY(d6, - FIX(1.847759065));
+ tmp3 = z1 + MULTIPLY(d2, FIX(0.765366865));
+
+ tmp0 = SCALE (d0 + d4, CONST_BITS);
+ tmp1 = SCALE (d0 - d4, CONST_BITS);
+
+ tmp10 = tmp0 + tmp3;
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp1 + tmp2;
+ tmp12 = tmp1 - tmp2;
+ } else {
+ /* d0 == 0, d2 != 0, d4 != 0, d6 != 0 */
+ z1 = MULTIPLY(d2 + d6, FIX(0.541196100));
+ tmp2 = z1 + MULTIPLY(d6, - FIX(1.847759065));
+ tmp3 = z1 + MULTIPLY(d2, FIX(0.765366865));
+
+ tmp0 = SCALE (d4, CONST_BITS);
+
+ tmp10 = tmp0 + tmp3;
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp2 - tmp0;
+ tmp12 = -(tmp0 + tmp2);
+ }
+ } else {
+ if (d0) {
+ /* d0 != 0, d2 == 0, d4 != 0, d6 != 0 */
+ tmp2 = MULTIPLY(d6, - FIX(1.306562965));
+ tmp3 = MULTIPLY(d6, FIX(0.541196100));
+
+ tmp0 = SCALE (d0 + d4, CONST_BITS);
+ tmp1 = SCALE (d0 - d4, CONST_BITS);
+
+ tmp10 = tmp0 + tmp3;
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp1 + tmp2;
+ tmp12 = tmp1 - tmp2;
+ } else {
+ /* d0 == 0, d2 == 0, d4 != 0, d6 != 0 */
+ tmp2 = MULTIPLY(d6, -FIX(1.306562965));
+ tmp3 = MULTIPLY(d6, FIX(0.541196100));
+
+ tmp0 = SCALE (d4, CONST_BITS);
+
+ tmp10 = tmp0 + tmp3;
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp2 - tmp0;
+ tmp12 = -(tmp0 + tmp2);
+ }
+ }
+ } else {
+ if (d2) {
+ if (d0) {
+ /* d0 != 0, d2 != 0, d4 == 0, d6 != 0 */
+ z1 = MULTIPLY(d2 + d6, FIX(0.541196100));
+ tmp2 = z1 + MULTIPLY(d6, - FIX(1.847759065));
+ tmp3 = z1 + MULTIPLY(d2, FIX(0.765366865));
+
+ tmp0 = SCALE (d0, CONST_BITS);
+
+ tmp10 = tmp0 + tmp3;
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp0 + tmp2;
+ tmp12 = tmp0 - tmp2;
+ } else {
+ /* d0 == 0, d2 != 0, d4 == 0, d6 != 0 */
+ z1 = MULTIPLY(d2 + d6, FIX(0.541196100));
+ tmp2 = z1 + MULTIPLY(d6, - FIX(1.847759065));
+ tmp3 = z1 + MULTIPLY(d2, FIX(0.765366865));
+
+ tmp10 = tmp3;
+ tmp13 = -tmp3;
+ tmp11 = tmp2;
+ tmp12 = -tmp2;
+ }
+ } else {
+ if (d0) {
+ /* d0 != 0, d2 == 0, d4 == 0, d6 != 0 */
+ tmp2 = MULTIPLY(d6, - FIX(1.306562965));
+ tmp3 = MULTIPLY(d6, FIX(0.541196100));
+
+ tmp0 = SCALE (d0, CONST_BITS);
+
+ tmp10 = tmp0 + tmp3;
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp0 + tmp2;
+ tmp12 = tmp0 - tmp2;
+ } else {
+ /* d0 == 0, d2 == 0, d4 == 0, d6 != 0 */
+ tmp2 = MULTIPLY(d6, - FIX(1.306562965));
+ tmp3 = MULTIPLY(d6, FIX(0.541196100));
+
+ tmp10 = tmp3;
+ tmp13 = -tmp3;
+ tmp11 = tmp2;
+ tmp12 = -tmp2;
+ }
+ }
+ }
+ } else {
+ if (d4) {
+ if (d2) {
+ if (d0) {
+ /* d0 != 0, d2 != 0, d4 != 0, d6 == 0 */
+ tmp2 = MULTIPLY(d2, FIX(0.541196100));
+ tmp3 = MULTIPLY(d2, FIX(1.306562965));
+
+ tmp0 = SCALE (d0 + d4, CONST_BITS);
+ tmp1 = SCALE (d0 - d4, CONST_BITS);
+
+ tmp10 = tmp0 + tmp3;
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp1 + tmp2;
+ tmp12 = tmp1 - tmp2;
+ } else {
+ /* d0 == 0, d2 != 0, d4 != 0, d6 == 0 */
+ tmp2 = MULTIPLY(d2, FIX(0.541196100));
+ tmp3 = MULTIPLY(d2, FIX(1.306562965));
+
+ tmp0 = SCALE (d4, CONST_BITS);
+
+ tmp10 = tmp0 + tmp3;
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp2 - tmp0;
+ tmp12 = -(tmp0 + tmp2);
+ }
+ } else {
+ if (d0) {
+ /* d0 != 0, d2 == 0, d4 != 0, d6 == 0 */
+ tmp10 = tmp13 = SCALE (d0 + d4, CONST_BITS);
+ tmp11 = tmp12 = SCALE (d0 - d4, CONST_BITS);
+ } else {
+ /* d0 == 0, d2 == 0, d4 != 0, d6 == 0 */
+ tmp10 = tmp13 = SCALE (d4, CONST_BITS);
+ tmp11 = tmp12 = -tmp10;
+ }
+ }
+ } else {
+ if (d2) {
+ if (d0) {
+ /* d0 != 0, d2 != 0, d4 == 0, d6 == 0 */
+ tmp2 = MULTIPLY(d2, FIX(0.541196100));
+ tmp3 = MULTIPLY(d2, FIX(1.306562965));
+
+ tmp0 = SCALE (d0, CONST_BITS);
+
+ tmp10 = tmp0 + tmp3;
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp0 + tmp2;
+ tmp12 = tmp0 - tmp2;
+ } else {
+ /* d0 == 0, d2 != 0, d4 == 0, d6 == 0 */
+ tmp2 = MULTIPLY(d2, FIX(0.541196100));
+ tmp3 = MULTIPLY(d2, FIX(1.306562965));
+
+ tmp10 = tmp3;
+ tmp13 = -tmp3;
+ tmp11 = tmp2;
+ tmp12 = -tmp2;
+ }
+ } else {
+ if (d0) {
+ /* d0 != 0, d2 == 0, d4 == 0, d6 == 0 */
+ tmp10 = tmp13 = tmp11 = tmp12 = SCALE (d0, CONST_BITS);
+ } else {
+ /* d0 == 0, d2 == 0, d4 == 0, d6 == 0 */
+ tmp10 = tmp13 = tmp11 = tmp12 = 0;
+ }
+ }
+ }
+ }
+
+ /* Odd part per figure 8; the matrix is unitary and hence its
+ * transpose is its inverse. i0..i3 are y7,y5,y3,y1 respectively.
+ */
+ if (d7) {
+ if (d5) {
+ if (d3) {
+ if (d1) {
+ /* d1 != 0, d3 != 0, d5 != 0, d7 != 0 */
+ z1 = d7 + d1;
+ z2 = d5 + d3;
+ z3 = d7 + d3;
+ z4 = d5 + d1;
+ z5 = MULTIPLY(z3 + z4, FIX(1.175875602));
+
+ tmp0 = MULTIPLY(d7, FIX(0.298631336));
+ tmp1 = MULTIPLY(d5, FIX(2.053119869));
+ tmp2 = MULTIPLY(d3, FIX(3.072711026));
+ tmp3 = MULTIPLY(d1, FIX(1.501321110));
+ z1 = MULTIPLY(z1, - FIX(0.899976223));
+ z2 = MULTIPLY(z2, - FIX(2.562915447));
+ z3 = MULTIPLY(z3, - FIX(1.961570560));
+ z4 = MULTIPLY(z4, - FIX(0.390180644));
+
+ z3 += z5;
+ z4 += z5;
+
+ tmp0 += z1 + z3;
+ tmp1 += z2 + z4;
+ tmp2 += z2 + z3;
+ tmp3 += z1 + z4;
+ } else {
+ /* d1 == 0, d3 != 0, d5 != 0, d7 != 0 */
+ z1 = d7;
+ z2 = d5 + d3;
+ z3 = d7 + d3;
+ z5 = MULTIPLY(z3 + d5, FIX(1.175875602));
+
+ tmp0 = MULTIPLY(d7, FIX(0.298631336));
+ tmp1 = MULTIPLY(d5, FIX(2.053119869));
+ tmp2 = MULTIPLY(d3, FIX(3.072711026));
+ z1 = MULTIPLY(d7, - FIX(0.899976223));
+ z2 = MULTIPLY(z2, - FIX(2.562915447));
+ z3 = MULTIPLY(z3, - FIX(1.961570560));
+ z4 = MULTIPLY(d5, - FIX(0.390180644));
+
+ z3 += z5;
+ z4 += z5;
+
+ tmp0 += z1 + z3;
+ tmp1 += z2 + z4;
+ tmp2 += z2 + z3;
+ tmp3 = z1 + z4;
+ }
+ } else {
+ if (d1) {
+ /* d1 != 0, d3 == 0, d5 != 0, d7 != 0 */
+ z1 = d7 + d1;
+ z2 = d5;
+ z3 = d7;
+ z4 = d5 + d1;
+ z5 = MULTIPLY(z3 + z4, FIX(1.175875602));
+
+ tmp0 = MULTIPLY(d7, FIX(0.298631336));
+ tmp1 = MULTIPLY(d5, FIX(2.053119869));
+ tmp3 = MULTIPLY(d1, FIX(1.501321110));
+ z1 = MULTIPLY(z1, - FIX(0.899976223));
+ z2 = MULTIPLY(d5, - FIX(2.562915447));
+ z3 = MULTIPLY(d7, - FIX(1.961570560));
+ z4 = MULTIPLY(z4, - FIX(0.390180644));
+
+ z3 += z5;
+ z4 += z5;
+
+ tmp0 += z1 + z3;
+ tmp1 += z2 + z4;
+ tmp2 = z2 + z3;
+ tmp3 += z1 + z4;
+ } else {
+ /* d1 == 0, d3 == 0, d5 != 0, d7 != 0 */
+ tmp0 = MULTIPLY(d7, - FIX(0.601344887));
+ z1 = MULTIPLY(d7, - FIX(0.899976223));
+ z3 = MULTIPLY(d7, - FIX(1.961570560));
+ tmp1 = MULTIPLY(d5, - FIX(0.509795578));
+ z2 = MULTIPLY(d5, - FIX(2.562915447));
+ z4 = MULTIPLY(d5, - FIX(0.390180644));
+ z5 = MULTIPLY(d5 + d7, FIX(1.175875602));
+
+ z3 += z5;
+ z4 += z5;
+
+ tmp0 += z3;
+ tmp1 += z4;
+ tmp2 = z2 + z3;
+ tmp3 = z1 + z4;
+ }
+ }
+ } else {
+ if (d3) {
+ if (d1) {
+ /* d1 != 0, d3 != 0, d5 == 0, d7 != 0 */
+ z1 = d7 + d1;
+ z3 = d7 + d3;
+ z5 = MULTIPLY(z3 + d1, FIX(1.175875602));
+
+ tmp0 = MULTIPLY(d7, FIX(0.298631336));
+ tmp2 = MULTIPLY(d3, FIX(3.072711026));
+ tmp3 = MULTIPLY(d1, FIX(1.501321110));
+ z1 = MULTIPLY(z1, - FIX(0.899976223));
+ z2 = MULTIPLY(d3, - FIX(2.562915447));
+ z3 = MULTIPLY(z3, - FIX(1.961570560));
+ z4 = MULTIPLY(d1, - FIX(0.390180644));
+
+ z3 += z5;
+ z4 += z5;
+
+ tmp0 += z1 + z3;
+ tmp1 = z2 + z4;
+ tmp2 += z2 + z3;
+ tmp3 += z1 + z4;
+ } else {
+ /* d1 == 0, d3 != 0, d5 == 0, d7 != 0 */
+ z3 = d7 + d3;
+
+ tmp0 = MULTIPLY(d7, - FIX(0.601344887));
+ z1 = MULTIPLY(d7, - FIX(0.899976223));
+ tmp2 = MULTIPLY(d3, FIX(0.509795579));
+ z2 = MULTIPLY(d3, - FIX(2.562915447));
+ z5 = MULTIPLY(z3, FIX(1.175875602));
+ z3 = MULTIPLY(z3, - FIX(0.785694958));
+
+ tmp0 += z3;
+ tmp1 = z2 + z5;
+ tmp2 += z3;
+ tmp3 = z1 + z5;
+ }
+ } else {
+ if (d1) {
+ /* d1 != 0, d3 == 0, d5 == 0, d7 != 0 */
+ z1 = d7 + d1;
+ z5 = MULTIPLY(z1, FIX(1.175875602));
+
+ z1 = MULTIPLY(z1, FIX(0.275899379));
+ z3 = MULTIPLY(d7, - FIX(1.961570560));
+ tmp0 = MULTIPLY(d7, - FIX(1.662939224));
+ z4 = MULTIPLY(d1, - FIX(0.390180644));
+ tmp3 = MULTIPLY(d1, FIX(1.111140466));
+
+ tmp0 += z1;
+ tmp1 = z4 + z5;
+ tmp2 = z3 + z5;
+ tmp3 += z1;
+ } else {
+ /* d1 == 0, d3 == 0, d5 == 0, d7 != 0 */
+ tmp0 = MULTIPLY(d7, - FIX(1.387039845));
+ tmp1 = MULTIPLY(d7, FIX(1.175875602));
+ tmp2 = MULTIPLY(d7, - FIX(0.785694958));
+ tmp3 = MULTIPLY(d7, FIX(0.275899379));
+ }
+ }
+ }
+ } else {
+ if (d5) {
+ if (d3) {
+ if (d1) {
+ /* d1 != 0, d3 != 0, d5 != 0, d7 == 0 */
+ z2 = d5 + d3;
+ z4 = d5 + d1;
+ z5 = MULTIPLY(d3 + z4, FIX(1.175875602));
+
+ tmp1 = MULTIPLY(d5, FIX(2.053119869));
+ tmp2 = MULTIPLY(d3, FIX(3.072711026));
+ tmp3 = MULTIPLY(d1, FIX(1.501321110));
+ z1 = MULTIPLY(d1, - FIX(0.899976223));
+ z2 = MULTIPLY(z2, - FIX(2.562915447));
+ z3 = MULTIPLY(d3, - FIX(1.961570560));
+ z4 = MULTIPLY(z4, - FIX(0.390180644));
+
+ z3 += z5;
+ z4 += z5;
+
+ tmp0 = z1 + z3;
+ tmp1 += z2 + z4;
+ tmp2 += z2 + z3;
+ tmp3 += z1 + z4;
+ } else {
+ /* d1 == 0, d3 != 0, d5 != 0, d7 == 0 */
+ z2 = d5 + d3;
+
+ z5 = MULTIPLY(z2, FIX(1.175875602));
+ tmp1 = MULTIPLY(d5, FIX(1.662939225));
+ z4 = MULTIPLY(d5, - FIX(0.390180644));
+ z2 = MULTIPLY(z2, - FIX(1.387039845));
+ tmp2 = MULTIPLY(d3, FIX(1.111140466));
+ z3 = MULTIPLY(d3, - FIX(1.961570560));
+
+ tmp0 = z3 + z5;
+ tmp1 += z2;
+ tmp2 += z2;
+ tmp3 = z4 + z5;
+ }
+ } else {
+ if (d1) {
+ /* d1 != 0, d3 == 0, d5 != 0, d7 == 0 */
+ z4 = d5 + d1;
+
+ z5 = MULTIPLY(z4, FIX(1.175875602));
+ z1 = MULTIPLY(d1, - FIX(0.899976223));
+ tmp3 = MULTIPLY(d1, FIX(0.601344887));
+ tmp1 = MULTIPLY(d5, - FIX(0.509795578));
+ z2 = MULTIPLY(d5, - FIX(2.562915447));
+ z4 = MULTIPLY(z4, FIX(0.785694958));
+
+ tmp0 = z1 + z5;
+ tmp1 += z4;
+ tmp2 = z2 + z5;
+ tmp3 += z4;
+ } else {
+ /* d1 == 0, d3 == 0, d5 != 0, d7 == 0 */
+ tmp0 = MULTIPLY(d5, FIX(1.175875602));
+ tmp1 = MULTIPLY(d5, FIX(0.275899380));
+ tmp2 = MULTIPLY(d5, - FIX(1.387039845));
+ tmp3 = MULTIPLY(d5, FIX(0.785694958));
+ }
+ }
+ } else {
+ if (d3) {
+ if (d1) {
+ /* d1 != 0, d3 != 0, d5 == 0, d7 == 0 */
+ z5 = d1 + d3;
+ tmp3 = MULTIPLY(d1, FIX(0.211164243));
+ tmp2 = MULTIPLY(d3, - FIX(1.451774981));
+ z1 = MULTIPLY(d1, FIX(1.061594337));
+ z2 = MULTIPLY(d3, - FIX(2.172734803));
+ z4 = MULTIPLY(z5, FIX(0.785694958));
+ z5 = MULTIPLY(z5, FIX(1.175875602));
+
+ tmp0 = z1 - z4;
+ tmp1 = z2 + z4;
+ tmp2 += z5;
+ tmp3 += z5;
+ } else {
+ /* d1 == 0, d3 != 0, d5 == 0, d7 == 0 */
+ tmp0 = MULTIPLY(d3, - FIX(0.785694958));
+ tmp1 = MULTIPLY(d3, - FIX(1.387039845));
+ tmp2 = MULTIPLY(d3, - FIX(0.275899379));
+ tmp3 = MULTIPLY(d3, FIX(1.175875602));
+ }
+ } else {
+ if (d1) {
+ /* d1 != 0, d3 == 0, d5 == 0, d7 == 0 */
+ tmp0 = MULTIPLY(d1, FIX(0.275899379));
+ tmp1 = MULTIPLY(d1, FIX(0.785694958));
+ tmp2 = MULTIPLY(d1, FIX(1.175875602));
+ tmp3 = MULTIPLY(d1, FIX(1.387039845));
+ } else {
+ /* d1 == 0, d3 == 0, d5 == 0, d7 == 0 */
+ tmp0 = tmp1 = tmp2 = tmp3 = 0;
+ }
+ }
+ }
+ }
+
+ /* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
+
+ dataptr[DCTSIZE*0] = (DCTELEM) DESCALE(tmp10 + tmp3,
+ CONST_BITS+PASS1_BITS+3);
+ dataptr[DCTSIZE*7] = (DCTELEM) DESCALE(tmp10 - tmp3,
+ CONST_BITS+PASS1_BITS+3);
+ dataptr[DCTSIZE*1] = (DCTELEM) DESCALE(tmp11 + tmp2,
+ CONST_BITS+PASS1_BITS+3);
+ dataptr[DCTSIZE*6] = (DCTELEM) DESCALE(tmp11 - tmp2,
+ CONST_BITS+PASS1_BITS+3);
+ dataptr[DCTSIZE*2] = (DCTELEM) DESCALE(tmp12 + tmp1,
+ CONST_BITS+PASS1_BITS+3);
+ dataptr[DCTSIZE*5] = (DCTELEM) DESCALE(tmp12 - tmp1,
+ CONST_BITS+PASS1_BITS+3);
+ dataptr[DCTSIZE*3] = (DCTELEM) DESCALE(tmp13 + tmp0,
+ CONST_BITS+PASS1_BITS+3);
+ dataptr[DCTSIZE*4] = (DCTELEM) DESCALE(tmp13 - tmp0,
+ CONST_BITS+PASS1_BITS+3);
+
+ dataptr++; /* advance pointer to next column */
+ }
+}
+
+#else
+
+/*---- debugging/tracing macros ----*/
+
+#if _MSC_VER
+#pragma optimize("",on)
+#if _MSC_VER > 700
+/*#pragma optimize("l",off)*/
+#endif
+#endif
+
+#define idct_single_pos0()
+#define idct_zero_col_stat()
+#define idct_zero_row_stat()
+#define idct_nonzero_col_stat()
+#define idct_nonzero_row_stat()
+#define DUMP_COEFS(p)
+#define TRACE(args)
+#define FAST_DCTPTRS 1
+
+#if 0 /* to count cases */
+void idct_single_pos0 (void) { static int count; count++; }
+void idct_zero_col_stat (void) { static int count; count++; }
+void idct_zero_row_stat (void) { static int count; count++; }
+void idct_nonzero_col_stat (void) { static int count; count++; }
+void idct_nonzero_row_stat (void) { static int count; count++; }
+#undef idct_single_pos0
+#undef idct_zero_col_stat
+#undef idct_zero_row_stat
+#undef idct_nonzero_col_stat
+#undef idct_nonzero_row_stat
+#endif
+
+void init_pre_idct (void) { }
+
+void j_rev_dct_sparse (DCTBLOCK data, int pos)
+{
+ /* If just DC Coefficient. */
+
+ if (pos == 0) {
+ register DCTELEM *dp, *dq;
+ DCTELEM dcval;
+
+ idct_single_pos0();
+
+ dp = data;
+ dcval = dp[0];
+ if (dcval < 0)
+ dcval = (short)((dcval - 3) >> 3);
+ else
+ dcval = (short)((dcval + 4) >> 3);
+
+ if (dcval) {
+ for (dq = dp + 64; dp < dq; dp += 8) {
+ dp[3] = dp[2] = dp[1] = dp[0] = dcval;
+ dp[7] = dp[6] = dp[5] = dp[4] = dcval;
+ }
+ }
+ return;
+ }
+
+ /* Some other coeff */
+ j_rev_dct (data);
+}
+
+#ifndef OPTIMIZE_ASM
+void j_rev_dct (DCTBLOCK data)
+{
+ INT32 tmp0, tmp1, tmp2, tmp3;
+ INT32 tmp10, tmp11, tmp12, tmp13;
+ INT32 z1, z2, z3, z4, z5;
+ register DCTELEM *dp;
+ int rowctr;
+ SHIFT_TEMPS;
+
+ /* Pass 1: process rows. */
+ /* Note results are scaled up by sqrt(8) compared to a true IDCT; */
+ /* furthermore, we scale the results by 2**PASS1_BITS. */
+
+ DUMP_COEFS(data);
+
+ dp = data;
+ for (rowctr = DCTSIZE-1; rowctr >= 0; rowctr--, dp += DCTSIZE) {
+ /* Due to quantization, we will usually find that many of the input
+ * coefficients are zero, especially the AC terms. We can exploit this
+ * by short-circuiting the IDCT calculation for any row in which all
+ * the AC terms are zero. In that case each output is equal to the
+ * DC coefficient (with scale factor as needed).
+ * With typical images and quantization tables, half or more of the
+ * row DCT calculations can be simplified this way.
+ */
+
+#if FAST_DCTPTRS
+#define d0 dp[0]
+#define d1 dp[1]
+#define d2 dp[2]
+#define d3 dp[3]
+#define d4 dp[4]
+#define d5 dp[5]
+#define d6 dp[6]
+#define d7 dp[7]
+#else
+ int d0 = dp[0];
+ int d1 = dp[1];
+ int d2 = dp[2];
+ int d3 = dp[3];
+ int d4 = dp[4];
+ int d5 = dp[5];
+ int d6 = dp[6];
+ int d7 = dp[7];
+#endif
+
+#ifndef NO_ZERO_ROW_TEST
+ if ((d1 | d2 | d3 | d4 | d5 | d6 | d7) == 0) {
+ /* AC terms all zero */
+ DCTELEM dcval = (DCTELEM) (d0 << PASS1_BITS);
+
+ if (d0) {
+ dp[0] = dcval;
+ dp[1] = dcval;
+ dp[2] = dcval;
+ dp[3] = dcval;
+ dp[4] = dcval;
+ dp[5] = dcval;
+ dp[6] = dcval;
+ dp[7] = dcval;
+ }
+ idct_zero_row_stat();
+ continue;
+ }
+#endif
+
+ idct_nonzero_row_stat();
+
+ /* Even part: reverse the even part of the forward DCT. */
+ /* The rotator is sqrt(2)*c(-6). */
+
+ z1 = MULTIPLY(d2 + d6, FIX(0.541196100));
+ tmp2 = z1 + MULTIPLY(d6, - FIX(1.847759065));
+ tmp3 = z1 + MULTIPLY(d2, FIX(0.765366865));
+
+ tmp0 = SCALE (d0 + d4, CONST_BITS);
+ tmp1 = SCALE (d0 - d4, CONST_BITS);
+
+ tmp10 = tmp0 + tmp3;
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp1 + tmp2;
+ tmp12 = tmp1 - tmp2;
+
+ /* Odd part per figure 8; the matrix is unitary and hence its
+ * transpose is its inverse. i0..i3 are y7,y5,y3,y1 respectively.
+ */
+
+ z1 = d7 + d1;
+ z2 = d5 + d3;
+ z3 = d7 + d3;
+ z4 = d5 + d1;
+ z5 = MULTIPLY(z3 + z4, FIX(1.175875602)); /* sqrt(2) * c3 */
+
+ tmp0 = MULTIPLY(d7, FIX(0.298631336)); /* sqrt(2) * (-c1+c3+c5-c7) */
+ tmp1 = MULTIPLY(d5, FIX(2.053119869)); /* sqrt(2) * ( c1+c3-c5+c7) */
+ tmp2 = MULTIPLY(d3, FIX(3.072711026)); /* sqrt(2) * ( c1+c3+c5-c7) */
+ tmp3 = MULTIPLY(d1, FIX(1.501321110)); /* sqrt(2) * ( c1+c3-c5-c7) */
+ z1 = MULTIPLY(z1, - FIX(0.899976223)); /* sqrt(2) * (c7-c3) */
+ z2 = MULTIPLY(z2, - FIX(2.562915447)); /* sqrt(2) * (-c1-c3) */
+ z3 = MULTIPLY(z3, - FIX(1.961570560)); /* sqrt(2) * (-c3-c5) */
+ z4 = MULTIPLY(z4, - FIX(0.390180644)); /* sqrt(2) * (c5-c3) */
+
+ z3 += z5;
+ z4 += z5;
+
+ tmp0 += z1 + z3;
+ tmp1 += z2 + z4;
+ tmp2 += z2 + z3;
+ tmp3 += z1 + z4;
+
+ /* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
+
+ dp[0] = (DCTELEM) DESCALE(tmp10 + tmp3, CONST_BITS-PASS1_BITS);
+ dp[7] = (DCTELEM) DESCALE(tmp10 - tmp3, CONST_BITS-PASS1_BITS);
+ dp[1] = (DCTELEM) DESCALE(tmp11 + tmp2, CONST_BITS-PASS1_BITS);
+ dp[6] = (DCTELEM) DESCALE(tmp11 - tmp2, CONST_BITS-PASS1_BITS);
+ dp[2] = (DCTELEM) DESCALE(tmp12 + tmp1, CONST_BITS-PASS1_BITS);
+ dp[5] = (DCTELEM) DESCALE(tmp12 - tmp1, CONST_BITS-PASS1_BITS);
+ dp[3] = (DCTELEM) DESCALE(tmp13 + tmp0, CONST_BITS-PASS1_BITS);
+ dp[4] = (DCTELEM) DESCALE(tmp13 - tmp0, CONST_BITS-PASS1_BITS);
+ }
+#if FAST_DCTPTRS
+#undef d0
+#undef d1
+#undef d2
+#undef d3
+#undef d4
+#undef d5
+#undef d6
+#undef d7
+#endif
+
+ /* Pass 2: process columns. */
+ /* Note that we must descale the results by a factor of 8 == 2**3, */
+ /* and also undo the PASS1_BITS scaling. */
+
+ dp = data;
+ for (rowctr = DCTSIZE-1; rowctr >= 0; rowctr--, dp++) {
+ /* Columns of zeroes can be exploited in the same way as we did with rows.
+ * However, the row calculation has created many nonzero AC terms, so the
+ * simplification applies less often (typically 5% to 10% of the time).
+ * On machines with very fast multiplication, it's possible that the
+ * test takes more time than it's worth. In that case this section
+ * may be commented out.
+ */
+
+#if FAST_DCTPTRS
+#define d0 dp[DCTSIZE*0]
+#define d1 dp[DCTSIZE*1]
+#define d2 dp[DCTSIZE*2]
+#define d3 dp[DCTSIZE*3]
+#define d4 dp[DCTSIZE*4]
+#define d5 dp[DCTSIZE*5]
+#define d6 dp[DCTSIZE*6]
+#define d7 dp[DCTSIZE*7]
+#else
+ int d0 = dp[DCTSIZE*0];
+ int d1 = dp[DCTSIZE*1];
+ int d2 = dp[DCTSIZE*2];
+ int d3 = dp[DCTSIZE*3];
+ int d4 = dp[DCTSIZE*4];
+ int d5 = dp[DCTSIZE*5];
+ int d6 = dp[DCTSIZE*6];
+ int d7 = dp[DCTSIZE*7];
+#endif
+
+#ifndef NO_ZERO_COLUMN_TEST
+ if ((d1 | d2 | d3 | d4 | d5 | d6 | d7) == 0) {
+ /* AC terms all zero */
+ DCTELEM dcval = (DCTELEM) DESCALE((INT32) d0, PASS1_BITS+3);
+
+ if (d0) {
+ dp[DCTSIZE*0] = dcval;
+ dp[DCTSIZE*1] = dcval;
+ dp[DCTSIZE*2] = dcval;
+ dp[DCTSIZE*3] = dcval;
+ dp[DCTSIZE*4] = dcval;
+ dp[DCTSIZE*5] = dcval;
+ dp[DCTSIZE*6] = dcval;
+ dp[DCTSIZE*7] = dcval;
+ }
+ idct_zero_col_stat();
+ continue;
+ }
+#endif
+
+ idct_nonzero_col_stat();
+
+ /* Even part: reverse the even part of the forward DCT. */
+ /* The rotator is sqrt(2)*c(-6). */
+
+ z1 = MULTIPLY(d2 + d6, FIX(0.541196100));
+ tmp2 = z1 + MULTIPLY(d6, - FIX(1.847759065));
+ tmp3 = z1 + MULTIPLY(d2, FIX(0.765366865));
+
+ tmp0 = SCALE (d0 + d4, CONST_BITS);
+ tmp1 = SCALE (d0 - d4, CONST_BITS);
+
+ tmp10 = tmp0 + tmp3;
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp1 + tmp2;
+ tmp12 = tmp1 - tmp2;
+
+ /* Odd part per figure 8; the matrix is unitary and hence its
+ * transpose is its inverse. i0..i3 are y7,y5,y3,y1 respectively.
+ */
+
+ z1 = d7 + d1;
+ z2 = d5 + d3;
+ z3 = d7 + d3;
+ z4 = d5 + d1;
+ z5 = MULTIPLY(z3 + z4, FIX(1.175875602)); /* sqrt(2) * c3 */
+
+ tmp0 = MULTIPLY(d7, FIX(0.298631336)); /* sqrt(2) * (-c1+c3+c5-c7) */
+ tmp1 = MULTIPLY(d5, FIX(2.053119869)); /* sqrt(2) * ( c1+c3-c5+c7) */
+ tmp2 = MULTIPLY(d3, FIX(3.072711026)); /* sqrt(2) * ( c1+c3+c5-c7) */
+ tmp3 = MULTIPLY(d1, FIX(1.501321110)); /* sqrt(2) * ( c1+c3-c5-c7) */
+ z1 = MULTIPLY(z1, - FIX(0.899976223)); /* sqrt(2) * (c7-c3) */
+ z2 = MULTIPLY(z2, - FIX(2.562915447)); /* sqrt(2) * (-c1-c3) */
+ z3 = MULTIPLY(z3, - FIX(1.961570560)); /* sqrt(2) * (-c3-c5) */
+ z4 = MULTIPLY(z4, - FIX(0.390180644)); /* sqrt(2) * (c5-c3) */
+
+ z3 += z5;
+ z4 += z5;
+
+ tmp0 += z1 + z3;
+ tmp1 += z2 + z4;
+ tmp2 += z2 + z3;
+ tmp3 += z1 + z4;
+
+ /* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
+
+ dp[DCTSIZE*0] = (DCTELEM)DESCALE(tmp10 + tmp3, CONST_BITS+PASS1_BITS+3);
+ dp[DCTSIZE*7] = (DCTELEM)DESCALE(tmp10 - tmp3, CONST_BITS+PASS1_BITS+3);
+ dp[DCTSIZE*1] = (DCTELEM)DESCALE(tmp11 + tmp2, CONST_BITS+PASS1_BITS+3);
+ dp[DCTSIZE*6] = (DCTELEM)DESCALE(tmp11 - tmp2, CONST_BITS+PASS1_BITS+3);
+ dp[DCTSIZE*2] = (DCTELEM)DESCALE(tmp12 + tmp1, CONST_BITS+PASS1_BITS+3);
+ dp[DCTSIZE*5] = (DCTELEM)DESCALE(tmp12 - tmp1, CONST_BITS+PASS1_BITS+3);
+ dp[DCTSIZE*3] = (DCTELEM)DESCALE(tmp13 + tmp0, CONST_BITS+PASS1_BITS+3);
+ dp[DCTSIZE*4] = (DCTELEM)DESCALE(tmp13 - tmp0, CONST_BITS+PASS1_BITS+3);
+ }
+#if FAST_DCTPTRS
+#undef d0
+#undef d1
+#undef d2
+#undef d3
+#undef d4
+#undef d5
+#undef d6
+#undef d7
+#endif
+}
+#endif /* optimize.asm */
+
+#endif
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