📄 skl_dct_c.c
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/********************************************************
* Some code. Copyright (C) 2003 by Pascal Massimino. *
* All Rights Reserved. (http://skal.planet-d.net) *
* For Educational/Academic use ONLY. See 'LICENSE.TXT'.*
********************************************************/
/*
* skl_dct16_LLM.cpp
*
* "Fast and precise" LLM implementation of FDCT/IDCT, where
* rotations are decomposed using:
* tmp = (x+y).cos t
* x' = tmp + y.(sin t - cos t)
* y' = tmp - x.(sin t + cos t)
*
* See details at http://skl.planet-d.net/coding/dct.html
* and at the end of this file...
*
* Reference (e.g.):
* Loeffler C., Ligtenberg A., and Moschytz C.S.:
* Practical Fast 1D DCT Algorithm with Eleven Multiplications,
* Proc. ICASSP 1989, 988-991.
*
* IEEE-1180-like error specs for FDCT:
* Peak error: 1.0000
* Peak MSE: 0.0340
* Overall MSE: 0.0200
* Peak ME: 0.0191
* Overall ME: -0.0033
*
* error specs for IDCT:
* Peak error: 1.0000
* Peak MSE: 0.0065
* Overall MSE: 0.0051
* Peak ME: 0.0015
* Overall ME: 0.0000
*
********************************************************/
//#include "skl.h"
#include <math.h>
#include "dsputil.h"
#include "skl_dct.h"
typedef DCTELEM TYPE;
typedef uint8_t SKL_BYTE;
//////////////////////////////////////////////////////////
#define LOAD_BUTF(m1, m2, a, b, tmp, S) \
(m1) = (S)[(a)] + (S)[(b)]; \
(m2) = (S)[(a)] - (S)[(b)]
#define BUTF(a, b, tmp) \
(tmp) = (a)+(b); \
(b) = (a)-(b); \
(a) = (tmp)
#define ROTATE(m1,m2,c,k1,k2,tmp,Fix,Rnd) \
(tmp) = ( (m1) + (m2) )*(c); \
(m1) *= k1; \
(m2) *= k2; \
(tmp) += (Rnd); \
(m1) = ((m1)+(tmp))>>(Fix); \
(m2) = ((m2)+(tmp))>>(Fix);
#define ROTATE2(m1,m2,c,k1,k2,tmp) \
(tmp) = ( (m1) + (m2) )*(c); \
(m1) *= k1; \
(m2) *= k2; \
(m1) = (m1)+(tmp); \
(m2) = (m2)+(tmp);
#define ROTATE0(m1,m2,c,k1,k2,tmp) \
(m1) = ( (m2) )*(c); \
(m2) = (m2)*k2+(m1);
#define SHIFTL(x,n) ((x)<<(n))
#define SHIFTR(x, n) ((x)>>(n))
#define HALF(n) (1<<((n)-1))
#define IPASS 3
#define FPASS 2
#define FIX 16
#if 1
#define ROT6_C 35468
#define ROT6_SmC 50159
#define ROT6_SpC 121095
#define ROT17_C 77062
#define ROT17_SmC 25571
#define ROT17_SpC 128553
#define ROT37_C 58981
#define ROT37_SmC 98391
#define ROT37_SpC 19571
#define ROT13_C 167963
#define ROT13_SmC 134553
#define ROT13_SpC 201373
#else
#define FX(x) ( (int)floor((x)*(1<<FIX) + .5 ) )
static const double c1 = cos(1.*M_PI/16);
static const double c2 = cos(2.*M_PI/16);
static const double c3 = cos(3.*M_PI/16);
static const double c4 = cos(4.*M_PI/16);
static const double c5 = cos(5.*M_PI/16);
static const double c6 = cos(6.*M_PI/16);
static const double c7 = cos(7.*M_PI/16);
static const int ROT6_C = FX(c2-c6); // 0.541
static const int ROT6_SmC = FX(2*c6); // 0.765
static const int ROT6_SpC = FX(2*c2); // 1.847
static const int ROT17_C = FX(c1+c7); // 1.175
static const int ROT17_SmC = FX(2*c7); // 0.390
static const int ROT17_SpC = FX(2*c1); // 1.961
static const int ROT37_C = FX((c3-c7)/c4); // 0.899
static const int ROT37_SmC = FX(2*(c5+c7)); // 1.501
static const int ROT37_SpC = FX(2*(c1-c3)); // 0.298
static const int ROT13_C = FX((c1+c3)/c4); // 2.562
static const int ROT13_SmC = FX(2*(c3+c7)); // 2.053
static const int ROT13_SpC = FX(2*(c1+c5)); // 3.072
#endif
//////////////////////////////////////////////////////////
void Skl_Dct16_C( TYPE *In )
{
TYPE *pIn;
int i;
pIn = In;
for(i=8; i>0; --i)
{
int mm0, mm1, mm2, mm3, mm4, mm5, mm6, mm7, Spill;
// odd
LOAD_BUTF(mm1,mm6, 1, 6, mm0, pIn);
LOAD_BUTF(mm2,mm5, 2, 5, mm0, pIn);
LOAD_BUTF(mm3,mm4, 3, 4, mm0, pIn);
LOAD_BUTF(mm0,mm7, 0, 7, Spill, pIn);
BUTF(mm1, mm2, Spill);
BUTF(mm0, mm3, Spill);
ROTATE(mm3, mm2, ROT6_C, ROT6_SmC, -ROT6_SpC, Spill, FIX-FPASS, HALF(FIX-FPASS));
pIn[2] = mm3;
pIn[6] = mm2;
BUTF(mm0, mm1, Spill);
pIn[0] = SHIFTL(mm0, FPASS);
pIn[4] = SHIFTL(mm1, FPASS);
// even
mm3 = mm5 + mm7;
mm2 = mm4 + mm6;
ROTATE(mm2, mm3, ROT17_C, -ROT17_SpC, -ROT17_SmC, mm0, FIX-FPASS, HALF(FIX-FPASS));
ROTATE(mm4, mm7, -ROT37_C, ROT37_SpC, ROT37_SmC, mm0, FIX-FPASS, HALF(FIX-FPASS));
mm7 += mm3;
mm4 += mm2;
pIn[1] = mm7;
pIn[7] = mm4;
ROTATE(mm5, mm6, -ROT13_C, ROT13_SmC, ROT13_SpC, mm0, FIX-FPASS, HALF(FIX-FPASS));
mm5 += mm3;
mm6 += mm2;
pIn[3] = mm6;
pIn[5] = mm5;
pIn += 8;
}
pIn = In;
for(i=8; i>0; --i)
{
int mm0, mm1, mm2, mm3, mm4, mm5, mm6, mm7, Spill;
// odd
LOAD_BUTF(mm1,mm6, 1*8, 6*8, mm0, pIn);
LOAD_BUTF(mm2,mm5, 2*8, 5*8, mm0, pIn);
BUTF(mm1, mm2, mm0);
LOAD_BUTF(mm3,mm4, 3*8, 4*8, mm0, pIn);
LOAD_BUTF(mm0,mm7, 0*8, 7*8, Spill, pIn);
BUTF(mm0, mm3, Spill);
ROTATE(mm3, mm2, ROT6_C, ROT6_SmC, -ROT6_SpC, Spill, 0, HALF(FIX+FPASS+3));
pIn[2*8] = (TYPE)SHIFTR(mm3,FIX+FPASS+3);
pIn[6*8] = (TYPE)SHIFTR(mm2,FIX+FPASS+3);
mm0 += HALF(FPASS+3) - 1;
BUTF(mm0, mm1, Spill);
pIn[0*8] = (TYPE)SHIFTR(mm0, FPASS+3);
pIn[4*8] = (TYPE)SHIFTR(mm1, FPASS+3);
// even
mm3 = mm5 + mm7;
mm2 = mm4 + mm6;
ROTATE(mm2, mm3, ROT17_C, -ROT17_SpC, -ROT17_SmC, mm0, 0, HALF(FIX+FPASS+3));
ROTATE2(mm4, mm7, -ROT37_C, ROT37_SpC, ROT37_SmC, mm0);
mm7 += mm3;
mm4 += mm2;
pIn[7*8] = (TYPE)SHIFTR(mm4,FIX+FPASS+3);
pIn[1*8] = (TYPE)SHIFTR(mm7,FIX+FPASS+3);
ROTATE2(mm5, mm6, -ROT13_C, ROT13_SmC, ROT13_SpC, mm0);
mm5 += mm3;
mm6 += mm2;
pIn[5*8] = (TYPE)SHIFTR(mm5,FIX+FPASS+3);
pIn[3*8] = (TYPE)SHIFTR(mm6,FIX+FPASS+3);
pIn++;
}
}
//////////////////////////////////////////////////////////
void Skl_IDct16_C( TYPE *In )
{
TYPE *pIn;
int i;
pIn = In;
for (i=8; i>0; --i)
{
int mm0, mm1, mm2, mm3, mm4, mm5, mm6, mm7, Spill;
// odd
mm4 = (int)pIn[7];
mm5 = (int)pIn[5];
mm6 = (int)pIn[3];
mm7 = (int)pIn[1];
mm2 = mm4 + mm6;
mm3 = mm5 + mm7;
ROTATE2(mm2, mm3, ROT17_C, -ROT17_SpC, -ROT17_SmC, mm1);
ROTATE2(mm4, mm7, -ROT37_C, ROT37_SpC, ROT37_SmC, mm1);
ROTATE2(mm5, mm6, -ROT13_C, ROT13_SmC, ROT13_SpC, mm1);
mm4 += mm2;
mm5 += mm3;
mm6 += mm2;
mm7 += mm3;
// even
mm3 = (int)pIn[2];
mm2 = (int)pIn[6];
ROTATE2(mm3, mm2, ROT6_C, ROT6_SmC, -ROT6_SpC, mm1);
LOAD_BUTF(mm0, mm1, 0, 4, Spill, pIn);
mm0 = SHIFTL(mm0, FIX) + HALF(FIX-IPASS);
mm1 = SHIFTL(mm1, FIX) + HALF(FIX-IPASS);
BUTF(mm0, mm3, Spill);
BUTF(mm1, mm2, Spill);
BUTF(mm0, mm7, Spill);
pIn[0] = SHIFTR(mm0, FIX-IPASS);
pIn[7] = SHIFTR(mm7, FIX-IPASS);
BUTF(mm1, mm6, mm0);
pIn[1] = SHIFTR(mm1, FIX-IPASS);
pIn[6] = SHIFTR(mm6, FIX-IPASS);
BUTF(mm2, mm5, mm0);
pIn[2] = SHIFTR(mm2, FIX-IPASS);
pIn[5] = SHIFTR(mm5, FIX-IPASS);
BUTF(mm3, mm4, mm0);
pIn[3] = SHIFTR(mm3, FIX-IPASS);
pIn[4] = SHIFTR(mm4, FIX-IPASS);
pIn += 8;
}
pIn = In;
for (i=8; i>0; --i)
{
int mm0, mm1, mm2, mm3, mm4, mm5, mm6, mm7, Spill;
// odd
mm4 = (int)pIn[7*8];
mm5 = (int)pIn[5*8];
mm6 = (int)pIn[3*8];
mm7 = (int)pIn[1*8];
mm2 = mm4 + mm6;
mm3 = mm5 + mm7;
ROTATE2(mm2, mm3, ROT17_C, -ROT17_SpC, -ROT17_SmC, mm1);
ROTATE2(mm4, mm7, -ROT37_C, ROT37_SpC, ROT37_SmC, mm1);
ROTATE2(mm5, mm6, -ROT13_C, ROT13_SmC, ROT13_SpC, mm1);
mm4 += mm2;
mm5 += mm3;
mm6 += mm2;
mm7 += mm3;
// even
mm3 = (int)pIn[2*8];
mm2 = (int)pIn[6*8];
ROTATE2(mm3, mm2, ROT6_C, ROT6_SmC, -ROT6_SpC, mm1);
LOAD_BUTF(mm0, mm1, 0*8, 4*8, Spill, pIn);
mm0 = SHIFTL(mm0, FIX) + HALF(FIX+IPASS+3);
mm1 = SHIFTL(mm1, FIX) + HALF(FIX+IPASS+3);
BUTF(mm0, mm3, Spill);
BUTF(mm1, mm2, Spill);
BUTF(mm0, mm7, Spill);
pIn[8*0] = (TYPE) SHIFTR(mm0, FIX+IPASS+3);
pIn[8*7] = (TYPE) SHIFTR(mm7, FIX+IPASS+3);
BUTF(mm1, mm6, mm0);
pIn[8*1] = (TYPE) SHIFTR(mm1, FIX+IPASS+3);
pIn[8*6] = (TYPE) SHIFTR(mm6, FIX+IPASS+3);
BUTF(mm2, mm5, mm0);
pIn[8*2] = (TYPE) SHIFTR(mm2, FIX+IPASS+3);
pIn[8*5] = (TYPE) SHIFTR(mm5, FIX+IPASS+3);
BUTF(mm3, mm4, mm0);
pIn[8*3] = (TYPE) SHIFTR(mm3, FIX+IPASS+3);
pIn[8*4] = (TYPE) SHIFTR(mm4, FIX+IPASS+3);
pIn++;
}
}
void Skl_IDct16_Sparse_C( TYPE *In )
{
TYPE *pIn;
int i;
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