/*
    Doom-inspired Q15.16 format used for most of everything.
    https://hackmd.io/9uRB9YbTSBW4Qz_2b8TyDw#Examples-2-DOOM
*/

#ifndef COM_FIXED_H
#define COM_FIXED_H

#include <stdint.h>

#define COM_FIXED_FRACBITS 16
#define COM_FIXED_FRACUNIT (1 << COM_FIXED_FRACBITS)

typedef int32_t com_fixed_t;

static inline com_fixed_t com_fixed_add(com_fixed_t a, com_fixed_t b) {
  return a + b;
}

static inline com_fixed_t com_fixed_sub(com_fixed_t a, com_fixed_t b) {
  return a - b;
}

static inline com_fixed_t com_fixed_mul(com_fixed_t a, com_fixed_t b) {
  return (com_fixed_t)(((int64_t)a * (int64_t)b) >> COM_FIXED_FRACBITS);
}

/* Note: this does not clamp for over/underflow cases */
static inline com_fixed_t com_fixed_div(com_fixed_t a, com_fixed_t b) {
  return (com_fixed_t)(((int64_t)a << COM_FIXED_FRACBITS) / (int64_t)b);
}

/* Approximate square root using Newton-Raphson in 2 iterations over small LUT*/
com_fixed_t com_fixed_sqrt(com_fixed_t a);

void com_fixed_print(com_fixed_t a);

#endif