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#include "types.h"
#ifndef FIXED_H
#define FIXED_H
#define FIX_SHIFT 8
#define HALF_FIX_SHIFT 4
#define FIX_SCALE ( 1 << FIX_SHIFT )
#define FIX_SCALE_FLOAT ((float)(FIX_SCALE))
typedef s32 FIXED;
static inline FIXED fixed_OverMultiply(FIXED a, FIXED b) {
// This should multiply two fixed-point numbers sacrificing a little
// accuracy in exchange for less chance of an overflow
return ((a >> HALF_FIX_SHIFT) * (b >> HALF_FIX_SHIFT));
}
static inline FIXED fixed_multiply (FIXED a, FIXED b) {
// Multiply two fixed numbers. Possibility of overflow.
return (a * b) >> FIX_SHIFT;
}
static inline FIXED fixed_divide(FIXED a, FIXED b) {
// Divide two fixed point numbers
if (b != 0){
return (a * FIX_SCALE) / b;
}
else {
// Return a large number if division by zero
// Hopefully this won't break anything :P
return 100000 << FIX_SHIFT;
}
}
static inline FIXED float_to_fixed(float a) {
// Convert a float to fixed point
return ((FIXED)(a * FIX_SCALE_FLOAT));
}
static inline float fixed_to_float(FIXED a) {
// Convert fixed point to float
return (a / FIX_SCALE_FLOAT);
}
static inline void swapFixed(FIXED *a, FIXED *b) {
// Swap two fixed point integer pointers
FIXED temp;
temp = *a;
*a = *b;
*b = temp;
}
static inline FIXED fixed_sqrt(FIXED a, int iterations) {
// Calculate square root of a fixed-point number using Binary-Search
FIXED low = 0;
FIXED high = a;
FIXED mid;
FIXED midSquared;
for (int i = 0; i < iterations; i++) {
mid = fixed_divide((low + high), 2 << FIX_SHIFT);
midSquared = fixed_OverMultiply(mid, mid);
if (midSquared == a) {
return mid;
}
else if (midSquared > a) {
high = mid;
}
else {
low = mid;
}
}
return mid;
}
#endif // FIXED_H
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