atomic.h

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#pragma once
#include <stdbool.h>
#include <stdint.h>

// Some embedded targets (e.g., ARMv6-M / RP2040) have no lock-free atomics.
// Clang then warns that builtins may not be lock-free (-Watomic-alignment).
// We accept the fallback and suppress the warning locally.
#if defined(__clang__)
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Watomic-alignment"
#endif

#ifdef __cplusplus
extern "C" {
#endif

typedef struct sys_atomic_t {
  uint32_t value;
} sys_atomic_t __attribute__((aligned(4)));

static inline void sys_atomic_init(sys_atomic_t *a, uint32_t initial) {
  __atomic_store_n(&a->value, initial, __ATOMIC_RELAXED);
}

static inline uint32_t sys_atomic_get(const sys_atomic_t *a) {
  return __atomic_load_n(&a->value, __ATOMIC_RELAXED);
}

static inline void sys_atomic_set(sys_atomic_t *a, uint32_t v) {
  __atomic_store_n(&a->value, v, __ATOMIC_RELAXED);
}

static inline uint32_t sys_atomic_inc(sys_atomic_t *a) {
  return __atomic_add_fetch(&a->value, 1, __ATOMIC_RELAXED);
}

static inline uint32_t sys_atomic_dec(sys_atomic_t *a) {
  return __atomic_sub_fetch(&a->value, 1, __ATOMIC_RELAXED);
}

static inline void sys_atomic_set_bits(sys_atomic_t *a, uint32_t mask) {
  (void)__atomic_fetch_or(&a->value, mask, __ATOMIC_RELAXED);
}

static inline void sys_atomic_clear_bits(sys_atomic_t *a, uint32_t mask) {
  (void)__atomic_fetch_and(&a->value, ~mask, __ATOMIC_RELAXED);
}

#if defined(__clang__)
#pragma clang diagnostic pop
#endif

#ifdef __cplusplus
}
#endif