Retro68/Raytracer/fixed.h

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/*
Copyright 2012 Wolfgang Thaller.
This file is part of Retro68.
Retro68 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.
Retro68 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 Retro68. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef FIXED_H
#define FIXED_H
#include <cstdint>
inline std::int32_t muls(std::int16_t x, std::int16_t y)
{
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return (std::int32_t)x*y;
}
inline std::uint32_t mulu(std::uint16_t x, std::uint16_t y)
{
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//return (std::uint32_t)x * y;
std::uint32_t res;
__asm("mulu %1, %0" : "=d"(res) : "d"(x), "0"(y));
return res;
}
inline std::int32_t mulsu(std::int16_t x, std::uint16_t y)
{
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//return (std::int32_t)a * (std::uint32_t)b;
std::int32_t res;
__asm("mulu %1, %0" : "=d"(res) : "d"(x), "0"(y));
if(x < 0)
res -= ((std::uint32_t)y) << 16;
return res;
}
#define COUNT_OP(var) ++var
class fixed
{
std::int32_t val;
public:
class raw {};
fixed(std::int32_t val, raw r) : val(val) {}
fixed() : val(0) {}
fixed(int x) : val((long)x << 16) {}
fixed(float f) : val(f * 65536) {}
//operator int() { return val >> 16; }
fixed operator+(fixed o) const { return fixed(val + o.val, raw()); }
fixed operator-(fixed o) const { return fixed(val - o.val, raw()); }
fixed operator*(fixed o) const {
COUNT_OP(nMul);
//return fixed((static_cast<long long>(val) * o.val) >> 16, raw());
int16_t a = val >> 16;
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int16_t c = o.val >> 16;
uint16_t b = val;
uint16_t d = o.val;
return fixed(((a*c) << 16)
+ mulsu(a,d) + mulsu(c,b)
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+ (mulu(b,d) >> 16),raw());
}
fixed operator/(fixed o) const { COUNT_OP(nDiv); return fixed((static_cast<long long>(val) << 16) / o.val, raw()); }
fixed operator-() const { return fixed(-val, raw()); }
fixed& operator+=(fixed o) { val += o.val; return *this; }
fixed& operator-=(fixed o) { val -= o.val; return *this; }
fixed& operator*=(fixed o) { return (*this = *this * o); }
bool operator== (fixed o) const { return val == o.val; }
bool operator!= (fixed o) const { return val != o.val; }
bool operator> (fixed o) const { return val > o.val; }
bool operator< (fixed o) const { return val < o.val; }
bool operator>= (fixed o) const { return val >= o.val; }
bool operator<= (fixed o) const { return val <= o.val; }
friend fixed sqrt(fixed f);
friend fixed floor(fixed f);
friend fixed operator*(fixed f, int x);
friend fixed operator*(int x, fixed f);
friend int floor_to_int(fixed f);
static long nMul;
static long nIMul;
static long nDiv;
static long nSqrt;
};
/*fixed operator*(fixed f, int x) { return fixed(f.val * x, fixed::raw()); }
fixed operator*(int x, fixed f) { return fixed(f.val * x, fixed::raw()); }*/
inline fixed operator*(fixed f, int c)
{
std::int16_t a = f.val >> 16;
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std::uint16_t b = f.val;
COUNT_OP(fixed::nIMul);
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return fixed(((a*c) << 16)
+ mulsu(c,b),fixed::raw());
}
inline fixed operator*(int x, fixed f) { return f*x; }
inline fixed operator*(fixed f, float x) { return f*fixed(x); }
inline fixed operator*(float x, fixed f) { return f*fixed(x); }
fixed sqrt(fixed f);
inline fixed floor(fixed f)
{
return fixed(f.val & 0xFFFF0000L, fixed::raw());
}
inline int floor_to_int(fixed f)
{
return f.val >> 16;
}
#endif // FIXED_H