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/*
* Musepack audio compression
* Copyright (C) 1999-2004 Buschmann/Klemm/Piecha/Wolf
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "mppenc.h"
#include "fastmath.h"
#ifdef FAST_MATH
const float tabatan2 [ 2*TABSTEP+1] [2];
const float tabcos [26*TABSTEP+1] [2];
const float tabsqrt_ex [256];
const float tabsqrt_m [ TABSTEP+1] [2];
void Init_FastMath ( void )
{
int i; mpc_floatint X, Y; double xm, x0, xp, x, y; float* p;
p = (float*) tabatan2;
for ( i = -TABSTEP; i <= TABSTEP; i++ ) {
xm = atan ((i-0.5)/TABSTEP);
x0 = atan ((i+0.0)/TABSTEP);
xp = atan ((i+0.5)/TABSTEP);
x = x0/2 + (xm + xp)/4;
y = xp - xm;
*p++ = x;
*p++ = y;
}
p = (float*) tabcos;
for ( i = -13*TABSTEP; i <= 13*TABSTEP; i++ ) {
xm = cos ((i-0.5)/TABSTEP);
x0 = cos ((i+0.0)/TABSTEP);
xp = cos ((i+0.5)/TABSTEP);
x = x0/2 + (xm + xp)/4;
y = xp - xm;
*p++ = x;
*p++ = y;
}
p = (float*) tabsqrt_ex;
for ( i = 0; i < 255; i++ ) {
X.n = (i << 23);
Y.n = (i << 23) + (1<<23) - 1;
*p++ = sqrt(X.f);
}
X.n = (255 << 23) - 1;
*p++ = sqrt(X.f);
p = (float*) tabsqrt_m;
for ( i = 1*TABSTEP; i <= 2*TABSTEP; i++ ) {
xm = sqrt ((i-0.5)/TABSTEP);
x0 = sqrt ((i+0.0)/TABSTEP);
xp = sqrt ((i+0.5)/TABSTEP);
x = x0/2 + (xm + xp)/4;
y = xp - xm;
*p++ = x;
*p++ = y;
}
}
#endif
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