ref: 29851f9c445d41cd82e422cb4b8c13fd2a13aea5
dir: /h/expon.h/
typedef struct {
SPFLOAT a, dur, b;
SPFLOAT val, incr;
uint32_t sdur, stime;
int init;
} sp_expon;
int sp_expon_create(sp_expon **p);
int sp_expon_destroy(sp_expon **p);
int sp_expon_init(sp_data *sp, sp_expon *p);
int sp_expon_compute(sp_data *sp, sp_expon *p, SPFLOAT *in, SPFLOAT *out);