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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include "ags/lib/allegro/fixed.h"
#include "ags/lib/allegro/error.h"
#include "ags/globals.h"
namespace AGS3 {
fixed ftofix(double x) {
if (x > 32767.0) {
*_G(allegro_errno) = AL_ERANGE;
return 0x7FFFFFFF;
}
if (x < -32767.0) {
*_G(allegro_errno) = AL_ERANGE;
return (fixed) - 0x7FFFFFFF;
}
return (fixed)(x * 65536.0 + (x < 0 ? -0.5 : 0.5));
}
double fixtof(fixed x) {
return (double)x / 65536.0;
}
fixed fixadd(fixed x, fixed y) {
fixed result = x + y;
if (result >= 0) {
if ((x < 0) && (y < 0)) {
*_G(allegro_errno) = AL_ERANGE;
return (fixed) - 0x7FFFFFFF;
} else
return result;
} else {
if ((x > 0) && (y > 0)) {
*_G(allegro_errno) = AL_ERANGE;
return 0x7FFFFFFF;
} else
return result;
}
}
fixed fixsub(fixed x, fixed y) {
fixed result = x - y;
if (result >= 0) {
if ((x < 0) && (y > 0)) {
*_G(allegro_errno) = AL_ERANGE;
return (fixed) - 0x7FFFFFFF;
} else
return result;
} else {
if ((x > 0) && (y < 0)) {
*_G(allegro_errno) = AL_ERANGE;
return 0x7FFFFFFF;
} else
return result;
}
}
fixed fixmul(fixed x, fixed y) {
int64 lx = x;
int64 ly = y;
int64 lres = (lx * ly);
if (lres > 0x7FFFFFFF0000LL) {
*_G(allegro_errno) = AL_ERANGE;
return 0x7FFFFFFF;
} else if (lres < -0x7FFFFFFF0000LL) {
*_G(allegro_errno) = AL_ERANGE;
return 0x80000000;
} else {
int res = lres >> 16;
return res;
}
}
fixed fixdiv(fixed x, fixed y) {
if (y == 0) {
*_G(allegro_errno) = AL_ERANGE;
return (fixed)(x < 0) ? -0x7FFFFFFF : 0x7FFFFFFF;
} else
return ftofix(fixtof(x) / fixtof(y));
}
int fixfloor(fixed x) {
// FIXME: GCC warning "this condition has identical branches [-Wduplicated-branches]" on this code i.e. both branches are functionally identical. Remove?
#if 0
/* (x >> 16) is not portable */
if (x >= 0)
return (x >> 16);
else
return ~((~x) >> 16);
#else
return (x >> 16);
#endif
}
int fixceil(fixed x) {
if (x > 0x7FFF0000) {
*_G(allegro_errno) = AL_ERANGE;
return 0x7FFF;
}
return fixfloor(x + 0xFFFF);
}
fixed itofix(int x) {
return x << 16;
}
int fixtoi(fixed x) {
return fixfloor(x) + ((x & 0x8000) >> 15);
}
fixed fixcos(fixed x) {
return _cos_tbl[((x + 0x4000) >> 15) & 0x1FF];
}
fixed fixsin(fixed x) {
return _cos_tbl[((x - 0x400000 + 0x4000) >> 15) & 0x1FF];
}
fixed fixtan(fixed x) {
return _tan_tbl[((x + 0x4000) >> 15) & 0xFF];
}
fixed fixacos(fixed x) {
if ((x < -65536) || (x > 65536)) {
*_G(allegro_errno) = AL_EDOM;
return 0;
}
return _acos_tbl[(x + 65536 + 127) >> 8];
}
fixed fixasin(fixed x) {
if ((x < -65536) || (x > 65536)) {
*_G(allegro_errno) = AL_EDOM;
return 0;
}
return 0x00400000 - _acos_tbl[(x + 65536 + 127) >> 8];
}
} // namespace AGS3
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