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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 "common/endian.h"
#include "m4/core/imath.h"
namespace M4 {
unsigned long sqrtul(unsigned long v) {
unsigned long r = 0, s;
#define STEP(k) s = r + (1L << k * 2); r >>= 1; \
if (s <= v) { v -= s; r |= (1L << k * 2); }
STEP(15);
STEP(14);
STEP(13);
STEP(12);
STEP(11);
STEP(10);
STEP(9);
STEP(8);
STEP(7);
STEP(6);
STEP(5);
STEP(4);
STEP(3);
STEP(2);
STEP(1);
STEP(0);
return r;
#undef STEP
}
int32 imath_min(int32 a, int32 b) {
return ((a < b) ? a : b);
}
int32 imath_max(int32 a, int32 b) {
return ((a > b) ? a : b);
}
int32 imath_abs(int32 a) {
return ((a >= 0) ? a : -a);
}
static int32 seed;
void imath_seed(int32 seednum) {
seed = seednum;
}
uint32 imath_random() {
return(seed = (25173 * seed + 13849) & 0xffff);
}
int32 imath_ranged_rand(int32 a, int32 b) {
int32 result;
result = (a + (((1 + imath_abs(b - a)) * imath_random()) >> 16));
return result;
}
frac16 imath_ranged_rand16(frac16 a, frac16 b) {
frac16 result;
result = ((a + MulSF16(1 + imath_abs(b - a), imath_random())));
return result;
}
bool imath_rand_bool(int max) {
return imath_ranged_rand(1, max) == 1;
}
frac16 dist2d(int32 x1, int32 y1, int32 x2, int32 y2) {
if ((x2 -= x1) < 0) x2 = -x2;
if ((y2 -= y1) < 0) y2 = -y2;
return (x2 + y2 - (((x2 > y2) ? y2 : x2) >> 1));
}
#define STEP(k) s = r + (1L << k * 2); r >>= 1; \
if (s <= v) { v -= s; r |= (1L << k * 2); }
frac16 SqrtF16(frac16 n) {
ulong r = 0, s, v;
v = (ulong)n;
STEP(15);
STEP(14);
STEP(13);
STEP(12);
STEP(11);
STEP(10);
STEP(9);
STEP(8);
STEP(7);
STEP(6);
STEP(5);
STEP(4);
STEP(3);
STEP(2);
STEP(1);
STEP(0);
return (frac16)r;
}
#define DIV_128_PI 0x28be61
frac16 ArcTan(frac16 x, frac16 y) {
double floatX, floatY, result;
frac16 fracResult;
floatX = (float)(x >> 16) + (float)((float)(x & 0xffff) / (float)65536);
floatY = (float)(y >> 16) + (float)((float)(y & 0xffff) / (float)65536);
result = atan2(floatY, floatX);
fracResult = (((int32)(floor(result))) << 16) + (int32)(floor((result - floor(result)) * 65536));
fracResult = MulSF16(fracResult, DIV_128_PI);
if (fracResult < 0) fracResult += 0x1000000;
return fracResult;
}
uint16 HighWord(uint32 n) {
return (uint16)(n >> 16);
}
uint16 LowWord(uint32 n) {
return (uint16)(n & 0xffff);
}
uint32 convert_intel32(uint32 a) {
return FROM_LE_32(a);
}
uint16 convert_intel16(uint16 a) {
return FROM_LE_16(a);
}
frac16 FixedMul(frac16 a, frac16 b) {
float ta = a;
float tb = b;
return (frac16)((ta * tb) / 65536.0);
}
frac16 FixedDiv(frac16 a, frac16 b) {
float ta = a;
float tb = b;
return (frac16)((ta / tb) * 65536.0);
}
frac16 FixedMulDiv(frac16 a, frac16 b, frac16 c) {
float ta = a;
float tb = b;
float tc = c;
return (frac16)((ta * tb) / tc);
}
} // namespace M4
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