SSTV-Decoder/include/systick.h

#pragma once

#include "derivative.h"
#include <stdbool.h>

static inline void spin(volatile uint32_t count) {
    while (count--) asm("nop");
}

// t: expiration time, prd: period
static inline bool timer_expired_ms(uint32_t *t, uint32_t prd) {
    if (ticks_ms + prd < *t) *t = 0;                         // Time wrapped? Reset timer
    if (*t == 0) *t = ticks_ms + prd;                        // First poll? Set expiration
    if (*t > ticks_ms) return false;                         // Not expired yet, return
    *t = (ticks_ms - *t) > prd ? ticks_ms + prd : *t + prd;  // Next expiration time
    return true;                                             // Expired, return true
}

static inline bool timer_expired_100us(uint32_t *t, uint32_t prd) {
    if (ticks_100us + prd < *t) *t = 0;                            // Time wrapped? Reset timer
    if (*t == 0) *t = ticks_100us + prd;                           // First poll? Set expiration
    if (*t > ticks_100us) return false;                            // Not expired yet, return
    *t = (ticks_100us - *t) > prd ? ticks_100us + prd : *t + prd;  // Next expiration time
    return true;                                                   // Expired, return true
}

static inline void delay_ms(uint32_t ms) {
    uint32_t start = ticks_ms;
    while (ticks_ms - start < ms) asm("nop");
}

static inline void delay_100us(uint32_t us) {
    uint32_t start = ticks_100us;
    while (ticks_100us - start < us) asm("nop");
}