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optimizing 4x4 idct

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Originally committed as revision 3514 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2004-09-26 16:33:39 +00:00
parent af2a9e8fdb
commit affbf0435a
1 changed files with 8 additions and 270 deletions
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278
libavcodec/jrevdct.c
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@ -1184,11 +1184,13 @@ void j_rev_dct4(DCTBLOCK data)
int32_t d0, d2, d4, d6;
register DCTELEM *dataptr;
int rowctr;
/* 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. */
data[0] += 4;
dataptr = data;
for (rowctr = DCTSIZE-1; rowctr >= 0; rowctr--) {
@ -1222,13 +1224,11 @@ void j_rev_dct4(DCTBLOCK data)
dataptr += DCTSTRIDE; /* advance pointer to next row */
continue;
}
/* 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);
@ -1241,21 +1241,7 @@ void j_rev_dct4(DCTBLOCK data)
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 = 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);
@ -1267,72 +1253,9 @@ void j_rev_dct4(DCTBLOCK data)
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 = 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 = 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 = 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);
@ -1344,62 +1267,11 @@ void j_rev_dct4(DCTBLOCK data)
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 = 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 = (d0 + d4) << CONST_BITS;
tmp11 = tmp12 = (d0 - d4) << CONST_BITS;
} else {
/* d0 == 0, d2 == 0, d4 != 0, d6 == 0 */
tmp10 = tmp13 = 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 = 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 = d0 << CONST_BITS;
} else {
/* d0 == 0, d2 == 0, d4 == 0, d6 == 0 */
tmp10 = tmp13 = tmp11 = tmp12 = 0;
}
}
}
}
/* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
@ -1434,9 +1306,7 @@ void j_rev_dct4(DCTBLOCK data)
/* 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);
@ -1449,21 +1319,7 @@ void j_rev_dct4(DCTBLOCK data)
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 = 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);
@ -1475,72 +1331,9 @@ void j_rev_dct4(DCTBLOCK data)
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 = 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 = 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 = 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);
@ -1552,74 +1345,19 @@ void j_rev_dct4(DCTBLOCK data)
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 = 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 = (d0 + d4) << CONST_BITS;
tmp11 = tmp12 = (d0 - d4) << CONST_BITS;
} else {
/* d0 == 0, d2 == 0, d4 != 0, d6 == 0 */
tmp10 = tmp13 = 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 = 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 = d0 << CONST_BITS;
} else {
/* d0 == 0, d2 == 0, d4 == 0, d6 == 0 */
tmp10 = tmp13 = tmp11 = tmp12 = 0;
}
}
}
}
/* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
dataptr[DCTSTRIDE*0] = (DCTELEM) DESCALE(tmp10,
CONST_BITS+PASS1_BITS+3);
dataptr[DCTSTRIDE*1] = (DCTELEM) DESCALE(tmp11,
CONST_BITS+PASS1_BITS+3);
dataptr[DCTSTRIDE*2] = (DCTELEM) DESCALE(tmp12,
CONST_BITS+PASS1_BITS+3);
dataptr[DCTSTRIDE*3] = (DCTELEM) DESCALE(tmp13,
CONST_BITS+PASS1_BITS+3);
dataptr[DCTSTRIDE*0] = tmp10 >> (CONST_BITS+PASS1_BITS+3);
dataptr[DCTSTRIDE*1] = tmp11 >> (CONST_BITS+PASS1_BITS+3);
dataptr[DCTSTRIDE*2] = tmp12 >> (CONST_BITS+PASS1_BITS+3);
dataptr[DCTSTRIDE*3] = tmp13 >> (CONST_BITS+PASS1_BITS+3);
dataptr++; /* advance pointer to next column */
}