math.h

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#ifndef OPENSNES_MATH_H
#define OPENSNES_MATH_H
 
#include <snes/types.h>
 
/* Removed on 2026-10-05 (1.0 plan, lot C): ease_in_quad, ease_out_quad.
 * The replacements are in docs/UPGRADING.md; `make check-upgrade` names them. */
 
/*============================================================================
 * Fixed-Point Type and Macros
 *============================================================================*/

typedef s16 fixed;

#define FIX(x) ((fixed)(s16)((u16)(x) << 8))

#define UNFIX(x) ((s16)((x) >> 8))

#define UNFIX_ROUND(x) ((s16)(((s32)(x) + 128) >> 8))   /* 32-bit sum: x + 128 overflowed s16 from 127.5 (until 2026-10-03) */

#define FIX_FRAC(x) ((u8)((x) & 0xFF))

#define FIX_MAKE(i, f) ((fixed)(((i) << 8) | (f)))
 
/*============================================================================
 * Fixed-Point Arithmetic
 *============================================================================*/

fixed fixMul(fixed a, fixed b);

fixed fixDiv(fixed a, fixed b);
 
/*============================================================================
 * Trigonometry (Lookup Tables)
 *============================================================================*/

fixed fixSin(u8 angle);

fixed fixCos(u8 angle);
 
/*============================================================================
 * Integer Math (Safe Alternatives)
 *============================================================================*/

u16 mul16(u16 a, u16 b);

u16 div16(u16 dividend, u16 divisor);

u16 mod16(u16 dividend, u16 divisor);
 
/*============================================================================
 * Utility Functions
 *============================================================================*/

fixed fixAbs(fixed x);

fixed fixClamp(fixed x, fixed min, fixed max);

fixed fixLerp(fixed a, fixed b, u16 t);
 
/*============================================================================
 * Square Root and Inverse Trigonometry
 *============================================================================*/

u16 sqrt16(u16 n);

fixed fixSqrt(fixed x);

u8 atan2_8(s16 dy, s16 dx);
 
/*============================================================================
 * Easing Curves (B6 final, 2026-05-22)
 *============================================================================*/

u8 easeInQuad(u8 t);

u8 easeOutQuad(u8 t);
 
#endif /* OPENSNES_MATH_H */