delaysystick overflow for large delay value

[sysytwl]

line 1577 mod follow
··· c

/**

• @brief Delays execution using the SysTick timer
• @param n Number of clock ticks to delay (64-bit for extended range)
• @note Clock tick duration depends on system clock frequency
  */
  void DelaySysTick( uint64_t n )
  {
  // Return immediately if no delay requested
  if (n == 0) return;

#if defined(CH32V003) || defined(CH32V00x)
// 24-bit SysTick counter, counting up
uint32_t start = SysTick->CNT;
uint32_t target = start + (uint32_t)n; // Truncate to 24-bit range

// Handle counter overflow case
if (target < start) {
    // Wait for counter to wrap around to 0
    while (SysTick->CNT >= start);
}
// Wait until target value is reached
while (SysTick->CNT < target);

#elif defined(CH32V20x) || defined(CH32V30x) || defined(CH32X03x) || defined(CH582_CH583) || defined(CH591_CH592)
// 32-bit SysTick counter, counting up
uint64_t start = SysTick->CNT;
uint64_t target = start + n;
// Wait until target value is reached
while (SysTick->CNT < target);

#elif defined(CH32V10x) || defined(CH570_CH572) || defined(CH584_CH585)
// Using CNTL register (lower 32 bits), counting up
uint32_t start = SysTick->CNTL;
uint32_t target = start + (uint32_t)n; // Truncate to 32-bit range

// Handle counter overflow case
if (target < start) {
    // Wait for counter to wrap around to 0
    while (SysTick->CNTL >= start);
}
// Wait until target value is reached
while (SysTick->CNTL < target);

#elif defined(CH571_CH573)
// Down-counting mode
uint64_t start = SysTick->CNT;
uint64_t target = start - n;

// Handle underflow case
if (target > start) {
    // Wait for counter to wrap around
    while (SysTick->CNT < start);
}
// Wait until target value is reached
while (SysTick->CNT > target);

#else
#error DelaySysTick not defined for this platform.
#endif
}

···

[cnlohr]

If you have a recommendation for a change, please commit a PR. The outline for doing so is:

1. "Fork" this repo using the "Fork" option when visiting this repo's page.
2. Clone a copy of your fork of this repo.
3. Typing checkout -b my_branch_with_fix
4. Making your changes.
5. Committing your changes.
6. push origin my_branch_with_fix
7. Clicking the link it gives you and writing it up, then submitting.

Then we can review it and I can look at your changes.

I hope that's helpful enough.

But also, in general, I think it's important for the user of these delay functions to check for overflows themselves, since being sloppy about it could yield unsigned overflows when doing the math.