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core/lib/atomic_c11: Add __atomic_test_and_set()

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This adds a previously missing library implementation for
`__atomic_test_and_set()`.
This commit is contained in:
Marian Buschsieweke 2025-11-16 20:52:18 +01:00
parent dcf4aa5627
commit 4588b67fb8
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1 changed files with 31 additions and 0 deletions
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core/lib/atomic_c11.c
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@ -268,6 +268,7 @@ TEMPLATE_ATOMIC_OP_FETCH_N(nand, &, 8, ~) /* __atomic_nand_fetch_8 */
#pragma redefine_extname __atomic_store_c __atomic_store
#pragma redefine_extname __atomic_exchange_c __atomic_exchange
#pragma redefine_extname __atomic_compare_exchange_c __atomic_compare_exchange
#pragma redefine_extname __atomic_test_and_set_c __atomic_test_and_set
/**
* @brief Atomic generic load
@ -376,6 +377,36 @@ bool __atomic_compare_exchange_c(size_t len, void *ptr, void *expected,
irq_restore(mask);
return ret;
}
/**
* This built-in function performs an atomic test-and-set operation on the byte
* at *ptr. The byte is set to some implementation defined nonzero “set” value
* and the return value is true if and only if the previous contents were “set”.
* It should be only used for operands of type bool or char. For other types
* only part of the value may be set.
*
* All memory orders are valid.
*
* @see https://gcc.gnu.org/onlinedocs/gcc/_005f_005fatomic-Builtins.html#index-_005f_005fatomic_005ftest_005fand_005fset
*
* @param[in,out] ptr Value to test and then set
* @param[in] memorder Ignored
*
* @retval true The value @p ptr was already set
* @retval false The value @p ptr was previously unset
*
* @pre @p ptr points to a value of `bool`
*/
bool __atomic_test_and_set_c(void *ptr, int memorder)
{
(void)memorder;
bool *target = ptr;
unsigned mask = irq_disable();
bool retval = *target;
*target = true;
irq_restore(mask);
return retval;
}
#if !defined(__llvm__) && !defined(__clang__)
/* Memory barrier helper function, for platforms without barrier instructions */
void __sync_synchronize(void) __attribute__((__weak__));