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+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+// Critical section based fallback implementations
+//
+// This module supports two different critical section implementations:
+// - Built-in "disable all interrupts".
+// - Call into the `critical-section` crate (which allows the user to plug any implementation).
+//
+// The `critical-section`-based fallback is enabled when the user asks for it with the `critical-section`
+// Cargo feature.
+//
+// The "disable interrupts" fallback is not sound on multi-core systems.
+// Also, this uses privileged instructions to disable interrupts, so it usually
+// doesn't work on unprivileged mode. Using this fallback in an environment where privileged
+// instructions are not available is also usually considered **unsound**,
+// although the details are system-dependent.
+//
+// Therefore, this implementation will only be enabled in one of the following cases:
+//
+// - When the user explicitly declares that the system is single-core and that
+// privileged instructions are available using an unsafe cfg.
+// - When we can safely assume that the system is single-core and that
+// privileged instructions are available on the system.
+//
+// AVR, which is single core[^avr1] and LLVM also generates code that disables
+// interrupts [^avr2] in atomic ops by default, is considered the latter.
+// MSP430 as well.
+//
+// See also README.md of this directory.
+//
+// [^avr1]: https://github.com/llvm/llvm-project/blob/llvmorg-17.0.0-rc2/llvm/lib/Target/AVR/AVRExpandPseudoInsts.cpp#L1074
+// [^avr2]: https://github.com/llvm/llvm-project/blob/llvmorg-17.0.0-rc2/llvm/test/CodeGen/AVR/atomics/load16.ll#L5
+
+// On some platforms, atomic load/store can be implemented in a more efficient
+// way than disabling interrupts. On MSP430, some RMWs that do not return the
+// previous value can also be optimized.
+//
+// Note: On single-core systems, it is okay to use critical session-based
+// CAS together with atomic load/store. The load/store will not be
+// called while interrupts are disabled, and since the load/store is
+// atomic, it is not affected by interrupts even if interrupts are enabled.
+#[cfg(not(any(target_arch = "avr", feature = "critical-section")))]
+use arch::atomic;
+
+#[cfg(not(feature = "critical-section"))]
+#[cfg_attr(
+ all(
+ target_arch = "arm",
+ any(target_feature = "mclass", portable_atomic_target_feature = "mclass"),
+ ),
+ path = "armv6m.rs"
+)]
+#[cfg_attr(
+ all(
+ target_arch = "arm",
+ not(any(target_feature = "mclass", portable_atomic_target_feature = "mclass")),
+ ),
+ path = "armv4t.rs"
+)]
+#[cfg_attr(target_arch = "avr", path = "avr.rs")]
+#[cfg_attr(target_arch = "msp430", path = "msp430.rs")]
+#[cfg_attr(any(target_arch = "riscv32", target_arch = "riscv64"), path = "riscv.rs")]
+#[cfg_attr(target_arch = "xtensa", path = "xtensa.rs")]
+mod arch;
+
+use core::{cell::UnsafeCell, sync::atomic::Ordering};
+
+// Critical section implementations might use locks internally.
+#[cfg(feature = "critical-section")]
+const IS_ALWAYS_LOCK_FREE: bool = false;
+
+// Consider atomic operations based on disabling interrupts on single-core
+// systems are lock-free. (We consider the pre-v6 ARM Linux's atomic operations
+// provided in a similar way by the Linux kernel to be lock-free.)
+#[cfg(not(feature = "critical-section"))]
+const IS_ALWAYS_LOCK_FREE: bool = true;
+
+#[cfg(feature = "critical-section")]
+#[inline]
+fn with<F, R>(f: F) -> R
+where
+ F: FnOnce() -> R,
+{
+ critical_section::with(|_| f())
+}
+
+#[cfg(not(feature = "critical-section"))]
+#[inline]
+fn with<F, R>(f: F) -> R
+where
+ F: FnOnce() -> R,
+{
+ // Get current interrupt state and disable interrupts
+ let state = arch::disable();
+
+ let r = f();
+
+ // Restore interrupt state
+ // SAFETY: the state was retrieved by the previous `disable`.
+ unsafe { arch::restore(state) }
+
+ r
+}
+
+#[cfg_attr(target_pointer_width = "16", repr(C, align(2)))]
+#[cfg_attr(target_pointer_width = "32", repr(C, align(4)))]
+#[cfg_attr(target_pointer_width = "64", repr(C, align(8)))]
+#[cfg_attr(target_pointer_width = "128", repr(C, align(16)))]
+pub(crate) struct AtomicPtr<T> {
+ p: UnsafeCell<*mut T>,
+}
+
+// SAFETY: any data races are prevented by disabling interrupts or
+// atomic intrinsics (see module-level comments).
+unsafe impl<T> Send for AtomicPtr<T> {}
+// SAFETY: any data races are prevented by disabling interrupts or
+// atomic intrinsics (see module-level comments).
+unsafe impl<T> Sync for AtomicPtr<T> {}
+
+impl<T> AtomicPtr<T> {
+ #[inline]
+ pub(crate) const fn new(p: *mut T) -> Self {
+ Self { p: UnsafeCell::new(p) }
+ }
+
+ #[inline]
+ pub(crate) fn is_lock_free() -> bool {
+ Self::is_always_lock_free()
+ }
+ #[inline]
+ pub(crate) const fn is_always_lock_free() -> bool {
+ IS_ALWAYS_LOCK_FREE
+ }
+
+ #[inline]
+ pub(crate) fn get_mut(&mut self) -> &mut *mut T {
+ // SAFETY: the mutable reference guarantees unique ownership.
+ // (UnsafeCell::get_mut requires Rust 1.50)
+ unsafe { &mut *self.p.get() }
+ }
+
+ #[inline]
+ pub(crate) fn into_inner(self) -> *mut T {
+ self.p.into_inner()
+ }
+
+ #[inline]
+ #[cfg_attr(all(debug_assertions, not(portable_atomic_no_track_caller)), track_caller)]
+ pub(crate) fn load(&self, order: Ordering) -> *mut T {
+ crate::utils::assert_load_ordering(order);
+ #[cfg(not(any(target_arch = "avr", feature = "critical-section")))]
+ {
+ self.as_native().load(order)
+ }
+ #[cfg(any(target_arch = "avr", feature = "critical-section"))]
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe { self.p.get().read() })
+ }
+
+ #[inline]
+ #[cfg_attr(all(debug_assertions, not(portable_atomic_no_track_caller)), track_caller)]
+ pub(crate) fn store(&self, ptr: *mut T, order: Ordering) {
+ crate::utils::assert_store_ordering(order);
+ #[cfg(not(any(target_arch = "avr", feature = "critical-section")))]
+ {
+ self.as_native().store(ptr, order);
+ }
+ #[cfg(any(target_arch = "avr", feature = "critical-section"))]
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe { self.p.get().write(ptr) });
+ }
+
+ #[inline]
+ pub(crate) fn swap(&self, ptr: *mut T, order: Ordering) -> *mut T {
+ let _ = order;
+ #[cfg(portable_atomic_force_amo)]
+ {
+ self.as_native().swap(ptr, order)
+ }
+ #[cfg(not(portable_atomic_force_amo))]
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe {
+ let prev = self.p.get().read();
+ self.p.get().write(ptr);
+ prev
+ })
+ }
+
+ #[inline]
+ #[cfg_attr(all(debug_assertions, not(portable_atomic_no_track_caller)), track_caller)]
+ pub(crate) fn compare_exchange(
+ &self,
+ current: *mut T,
+ new: *mut T,
+ success: Ordering,
+ failure: Ordering,
+ ) -> Result<*mut T, *mut T> {
+ crate::utils::assert_compare_exchange_ordering(success, failure);
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe {
+ let prev = self.p.get().read();
+ if prev == current {
+ self.p.get().write(new);
+ Ok(prev)
+ } else {
+ Err(prev)
+ }
+ })
+ }
+
+ #[inline]
+ #[cfg_attr(all(debug_assertions, not(portable_atomic_no_track_caller)), track_caller)]
+ pub(crate) fn compare_exchange_weak(
+ &self,
+ current: *mut T,
+ new: *mut T,
+ success: Ordering,
+ failure: Ordering,
+ ) -> Result<*mut T, *mut T> {
+ self.compare_exchange(current, new, success, failure)
+ }
+
+ #[inline]
+ pub(crate) const fn as_ptr(&self) -> *mut *mut T {
+ self.p.get()
+ }
+
+ #[cfg(not(any(target_arch = "avr", feature = "critical-section")))]
+ #[inline]
+ fn as_native(&self) -> &atomic::AtomicPtr<T> {
+ // SAFETY: AtomicPtr and atomic::AtomicPtr have the same layout and
+ // guarantee atomicity in a compatible way. (see module-level comments)
+ unsafe { &*(self as *const Self as *const atomic::AtomicPtr<T>) }
+ }
+}
+
+macro_rules! atomic_int {
+ (base, $atomic_type:ident, $int_type:ident, $align:literal) => {
+ #[repr(C, align($align))]
+ pub(crate) struct $atomic_type {
+ v: UnsafeCell<$int_type>,
+ }
+
+ // Send is implicitly implemented.
+ // SAFETY: any data races are prevented by disabling interrupts or
+ // atomic intrinsics (see module-level comments).
+ unsafe impl Sync for $atomic_type {}
+
+ impl $atomic_type {
+ #[inline]
+ pub(crate) const fn new(v: $int_type) -> Self {
+ Self { v: UnsafeCell::new(v) }
+ }
+
+ #[inline]
+ pub(crate) fn is_lock_free() -> bool {
+ Self::is_always_lock_free()
+ }
+ #[inline]
+ pub(crate) const fn is_always_lock_free() -> bool {
+ IS_ALWAYS_LOCK_FREE
+ }
+
+ #[inline]
+ pub(crate) fn get_mut(&mut self) -> &mut $int_type {
+ // SAFETY: the mutable reference guarantees unique ownership.
+ // (UnsafeCell::get_mut requires Rust 1.50)
+ unsafe { &mut *self.v.get() }
+ }
+
+ #[inline]
+ pub(crate) fn into_inner(self) -> $int_type {
+ self.v.into_inner()
+ }
+
+ #[inline]
+ pub(crate) const fn as_ptr(&self) -> *mut $int_type {
+ self.v.get()
+ }
+ }
+ };
+ (load_store_atomic $([$kind:ident])?, $atomic_type:ident, $int_type:ident, $align:literal) => {
+ atomic_int!(base, $atomic_type, $int_type, $align);
+ #[cfg(not(portable_atomic_force_amo))]
+ atomic_int!(cas[emulate], $atomic_type, $int_type);
+ #[cfg(portable_atomic_force_amo)]
+ atomic_int!(cas $([$kind])?, $atomic_type, $int_type);
+ impl $atomic_type {
+ #[inline]
+ #[cfg_attr(all(debug_assertions, not(portable_atomic_no_track_caller)), track_caller)]
+ pub(crate) fn load(&self, order: Ordering) -> $int_type {
+ crate::utils::assert_load_ordering(order);
+ #[cfg(not(any(target_arch = "avr", feature = "critical-section")))]
+ {
+ self.as_native().load(order)
+ }
+ #[cfg(any(target_arch = "avr", feature = "critical-section"))]
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe { self.v.get().read() })
+ }
+
+ #[inline]
+ #[cfg_attr(all(debug_assertions, not(portable_atomic_no_track_caller)), track_caller)]
+ pub(crate) fn store(&self, val: $int_type, order: Ordering) {
+ crate::utils::assert_store_ordering(order);
+ #[cfg(not(any(target_arch = "avr", feature = "critical-section")))]
+ {
+ self.as_native().store(val, order);
+ }
+ #[cfg(any(target_arch = "avr", feature = "critical-section"))]
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe { self.v.get().write(val) });
+ }
+
+ #[cfg(not(any(target_arch = "avr", feature = "critical-section")))]
+ #[inline]
+ fn as_native(&self) -> &atomic::$atomic_type {
+ // SAFETY: $atomic_type and atomic::$atomic_type have the same layout and
+ // guarantee atomicity in a compatible way. (see module-level comments)
+ unsafe { &*(self as *const Self as *const atomic::$atomic_type) }
+ }
+ }
+
+ #[cfg(not(all(target_arch = "msp430", not(feature = "critical-section"))))]
+ impl_default_no_fetch_ops!($atomic_type, $int_type);
+ impl_default_bit_opts!($atomic_type, $int_type);
+ #[cfg(not(all(target_arch = "msp430", not(feature = "critical-section"))))]
+ impl $atomic_type {
+ #[inline]
+ pub(crate) fn not(&self, order: Ordering) {
+ self.fetch_not(order);
+ }
+ }
+ #[cfg(all(target_arch = "msp430", not(feature = "critical-section")))]
+ impl $atomic_type {
+ #[inline]
+ pub(crate) fn add(&self, val: $int_type, order: Ordering) {
+ self.as_native().add(val, order);
+ }
+ #[inline]
+ pub(crate) fn sub(&self, val: $int_type, order: Ordering) {
+ self.as_native().sub(val, order);
+ }
+ #[inline]
+ pub(crate) fn and(&self, val: $int_type, order: Ordering) {
+ self.as_native().and(val, order);
+ }
+ #[inline]
+ pub(crate) fn or(&self, val: $int_type, order: Ordering) {
+ self.as_native().or(val, order);
+ }
+ #[inline]
+ pub(crate) fn xor(&self, val: $int_type, order: Ordering) {
+ self.as_native().xor(val, order);
+ }
+ #[inline]
+ pub(crate) fn not(&self, order: Ordering) {
+ self.as_native().not(order);
+ }
+ }
+ };
+ (load_store_critical_session, $atomic_type:ident, $int_type:ident, $align:literal) => {
+ atomic_int!(base, $atomic_type, $int_type, $align);
+ atomic_int!(cas[emulate], $atomic_type, $int_type);
+ impl_default_no_fetch_ops!($atomic_type, $int_type);
+ impl_default_bit_opts!($atomic_type, $int_type);
+ impl $atomic_type {
+ #[inline]
+ #[cfg_attr(all(debug_assertions, not(portable_atomic_no_track_caller)), track_caller)]
+ pub(crate) fn load(&self, order: Ordering) -> $int_type {
+ crate::utils::assert_load_ordering(order);
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe { self.v.get().read() })
+ }
+
+ #[inline]
+ #[cfg_attr(all(debug_assertions, not(portable_atomic_no_track_caller)), track_caller)]
+ pub(crate) fn store(&self, val: $int_type, order: Ordering) {
+ crate::utils::assert_store_ordering(order);
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe { self.v.get().write(val) });
+ }
+
+ #[inline]
+ pub(crate) fn not(&self, order: Ordering) {
+ self.fetch_not(order);
+ }
+ }
+ };
+ (cas[emulate], $atomic_type:ident, $int_type:ident) => {
+ impl $atomic_type {
+ #[inline]
+ pub(crate) fn swap(&self, val: $int_type, _order: Ordering) -> $int_type {
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe {
+ let prev = self.v.get().read();
+ self.v.get().write(val);
+ prev
+ })
+ }
+
+ #[inline]
+ #[cfg_attr(all(debug_assertions, not(portable_atomic_no_track_caller)), track_caller)]
+ pub(crate) fn compare_exchange(
+ &self,
+ current: $int_type,
+ new: $int_type,
+ success: Ordering,
+ failure: Ordering,
+ ) -> Result<$int_type, $int_type> {
+ crate::utils::assert_compare_exchange_ordering(success, failure);
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe {
+ let prev = self.v.get().read();
+ if prev == current {
+ self.v.get().write(new);
+ Ok(prev)
+ } else {
+ Err(prev)
+ }
+ })
+ }
+
+ #[inline]
+ #[cfg_attr(all(debug_assertions, not(portable_atomic_no_track_caller)), track_caller)]
+ pub(crate) fn compare_exchange_weak(
+ &self,
+ current: $int_type,
+ new: $int_type,
+ success: Ordering,
+ failure: Ordering,
+ ) -> Result<$int_type, $int_type> {
+ self.compare_exchange(current, new, success, failure)
+ }
+
+ #[inline]
+ pub(crate) fn fetch_add(&self, val: $int_type, _order: Ordering) -> $int_type {
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe {
+ let prev = self.v.get().read();
+ self.v.get().write(prev.wrapping_add(val));
+ prev
+ })
+ }
+
+ #[inline]
+ pub(crate) fn fetch_sub(&self, val: $int_type, _order: Ordering) -> $int_type {
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe {
+ let prev = self.v.get().read();
+ self.v.get().write(prev.wrapping_sub(val));
+ prev
+ })
+ }
+
+ #[inline]
+ pub(crate) fn fetch_and(&self, val: $int_type, _order: Ordering) -> $int_type {
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe {
+ let prev = self.v.get().read();
+ self.v.get().write(prev & val);
+ prev
+ })
+ }
+
+ #[inline]
+ pub(crate) fn fetch_nand(&self, val: $int_type, _order: Ordering) -> $int_type {
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe {
+ let prev = self.v.get().read();
+ self.v.get().write(!(prev & val));
+ prev
+ })
+ }
+
+ #[inline]
+ pub(crate) fn fetch_or(&self, val: $int_type, _order: Ordering) -> $int_type {
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe {
+ let prev = self.v.get().read();
+ self.v.get().write(prev | val);
+ prev
+ })
+ }
+
+ #[inline]
+ pub(crate) fn fetch_xor(&self, val: $int_type, _order: Ordering) -> $int_type {
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe {
+ let prev = self.v.get().read();
+ self.v.get().write(prev ^ val);
+ prev
+ })
+ }
+
+ #[inline]
+ pub(crate) fn fetch_max(&self, val: $int_type, _order: Ordering) -> $int_type {
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe {
+ let prev = self.v.get().read();
+ self.v.get().write(core::cmp::max(prev, val));
+ prev
+ })
+ }
+
+ #[inline]
+ pub(crate) fn fetch_min(&self, val: $int_type, _order: Ordering) -> $int_type {
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe {
+ let prev = self.v.get().read();
+ self.v.get().write(core::cmp::min(prev, val));
+ prev
+ })
+ }
+
+ #[inline]
+ pub(crate) fn fetch_not(&self, _order: Ordering) -> $int_type {
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe {
+ let prev = self.v.get().read();
+ self.v.get().write(!prev);
+ prev
+ })
+ }
+
+ #[inline]
+ pub(crate) fn fetch_neg(&self, _order: Ordering) -> $int_type {
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe {
+ let prev = self.v.get().read();
+ self.v.get().write(prev.wrapping_neg());
+ prev
+ })
+ }
+ #[inline]
+ pub(crate) fn neg(&self, order: Ordering) {
+ self.fetch_neg(order);
+ }
+ }
+ };
+ // cfg(portable_atomic_force_amo) 32-bit(RV32)/{32,64}-bit(RV64) RMW
+ (cas, $atomic_type:ident, $int_type:ident) => {
+ impl $atomic_type {
+ #[inline]
+ pub(crate) fn swap(&self, val: $int_type, order: Ordering) -> $int_type {
+ self.as_native().swap(val, order)
+ }
+
+ #[inline]
+ #[cfg_attr(all(debug_assertions, not(portable_atomic_no_track_caller)), track_caller)]
+ pub(crate) fn compare_exchange(
+ &self,
+ current: $int_type,
+ new: $int_type,
+ success: Ordering,
+ failure: Ordering,
+ ) -> Result<$int_type, $int_type> {
+ crate::utils::assert_compare_exchange_ordering(success, failure);
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe {
+ let prev = self.v.get().read();
+ if prev == current {
+ self.v.get().write(new);
+ Ok(prev)
+ } else {
+ Err(prev)
+ }
+ })
+ }
+
+ #[inline]
+ #[cfg_attr(all(debug_assertions, not(portable_atomic_no_track_caller)), track_caller)]
+ pub(crate) fn compare_exchange_weak(
+ &self,
+ current: $int_type,
+ new: $int_type,
+ success: Ordering,
+ failure: Ordering,
+ ) -> Result<$int_type, $int_type> {
+ self.compare_exchange(current, new, success, failure)
+ }
+
+ #[inline]
+ pub(crate) fn fetch_add(&self, val: $int_type, order: Ordering) -> $int_type {
+ self.as_native().fetch_add(val, order)
+ }
+ #[inline]
+ pub(crate) fn fetch_sub(&self, val: $int_type, order: Ordering) -> $int_type {
+ self.as_native().fetch_sub(val, order)
+ }
+ #[inline]
+ pub(crate) fn fetch_and(&self, val: $int_type, order: Ordering) -> $int_type {
+ self.as_native().fetch_and(val, order)
+ }
+
+ #[inline]
+ pub(crate) fn fetch_nand(&self, val: $int_type, _order: Ordering) -> $int_type {
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe {
+ let prev = self.v.get().read();
+ self.v.get().write(!(prev & val));
+ prev
+ })
+ }
+
+ #[inline]
+ pub(crate) fn fetch_or(&self, val: $int_type, order: Ordering) -> $int_type {
+ self.as_native().fetch_or(val, order)
+ }
+ #[inline]
+ pub(crate) fn fetch_xor(&self, val: $int_type, order: Ordering) -> $int_type {
+ self.as_native().fetch_xor(val, order)
+ }
+ #[inline]
+ pub(crate) fn fetch_max(&self, val: $int_type, order: Ordering) -> $int_type {
+ self.as_native().fetch_max(val, order)
+ }
+ #[inline]
+ pub(crate) fn fetch_min(&self, val: $int_type, order: Ordering) -> $int_type {
+ self.as_native().fetch_min(val, order)
+ }
+ #[inline]
+ pub(crate) fn fetch_not(&self, order: Ordering) -> $int_type {
+ self.as_native().fetch_not(order)
+ }
+
+ #[inline]
+ pub(crate) fn fetch_neg(&self, _order: Ordering) -> $int_type {
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe {
+ let prev = self.v.get().read();
+ self.v.get().write(prev.wrapping_neg());
+ prev
+ })
+ }
+ #[inline]
+ pub(crate) fn neg(&self, order: Ordering) {
+ self.fetch_neg(order);
+ }
+ }
+ };
+ // cfg(portable_atomic_force_amo) {8,16}-bit RMW
+ (cas[sub_word], $atomic_type:ident, $int_type:ident) => {
+ impl $atomic_type {
+ #[inline]
+ pub(crate) fn swap(&self, val: $int_type, _order: Ordering) -> $int_type {
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe {
+ let prev = self.v.get().read();
+ self.v.get().write(val);
+ prev
+ })
+ }
+
+ #[inline]
+ #[cfg_attr(all(debug_assertions, not(portable_atomic_no_track_caller)), track_caller)]
+ pub(crate) fn compare_exchange(
+ &self,
+ current: $int_type,
+ new: $int_type,
+ success: Ordering,
+ failure: Ordering,
+ ) -> Result<$int_type, $int_type> {
+ crate::utils::assert_compare_exchange_ordering(success, failure);
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe {
+ let prev = self.v.get().read();
+ if prev == current {
+ self.v.get().write(new);
+ Ok(prev)
+ } else {
+ Err(prev)
+ }
+ })
+ }
+
+ #[inline]
+ #[cfg_attr(all(debug_assertions, not(portable_atomic_no_track_caller)), track_caller)]
+ pub(crate) fn compare_exchange_weak(
+ &self,
+ current: $int_type,
+ new: $int_type,
+ success: Ordering,
+ failure: Ordering,
+ ) -> Result<$int_type, $int_type> {
+ self.compare_exchange(current, new, success, failure)
+ }
+
+ #[inline]
+ pub(crate) fn fetch_add(&self, val: $int_type, _order: Ordering) -> $int_type {
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe {
+ let prev = self.v.get().read();
+ self.v.get().write(prev.wrapping_add(val));
+ prev
+ })
+ }
+
+ #[inline]
+ pub(crate) fn fetch_sub(&self, val: $int_type, _order: Ordering) -> $int_type {
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe {
+ let prev = self.v.get().read();
+ self.v.get().write(prev.wrapping_sub(val));
+ prev
+ })
+ }
+
+ #[inline]
+ pub(crate) fn fetch_and(&self, val: $int_type, order: Ordering) -> $int_type {
+ self.as_native().fetch_and(val, order)
+ }
+
+ #[inline]
+ pub(crate) fn fetch_nand(&self, val: $int_type, _order: Ordering) -> $int_type {
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe {
+ let prev = self.v.get().read();
+ self.v.get().write(!(prev & val));
+ prev
+ })
+ }
+
+ #[inline]
+ pub(crate) fn fetch_or(&self, val: $int_type, order: Ordering) -> $int_type {
+ self.as_native().fetch_or(val, order)
+ }
+ #[inline]
+ pub(crate) fn fetch_xor(&self, val: $int_type, order: Ordering) -> $int_type {
+ self.as_native().fetch_xor(val, order)
+ }
+
+ #[inline]
+ pub(crate) fn fetch_max(&self, val: $int_type, _order: Ordering) -> $int_type {
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe {
+ let prev = self.v.get().read();
+ self.v.get().write(core::cmp::max(prev, val));
+ prev
+ })
+ }
+
+ #[inline]
+ pub(crate) fn fetch_min(&self, val: $int_type, _order: Ordering) -> $int_type {
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe {
+ let prev = self.v.get().read();
+ self.v.get().write(core::cmp::min(prev, val));
+ prev
+ })
+ }
+
+ #[inline]
+ pub(crate) fn fetch_not(&self, order: Ordering) -> $int_type {
+ self.as_native().fetch_not(order)
+ }
+
+ #[inline]
+ pub(crate) fn fetch_neg(&self, _order: Ordering) -> $int_type {
+ // SAFETY: any data races are prevented by disabling interrupts (see
+ // module-level comments) and the raw pointer is valid because we got it
+ // from a reference.
+ with(|| unsafe {
+ let prev = self.v.get().read();
+ self.v.get().write(prev.wrapping_neg());
+ prev
+ })
+ }
+ #[inline]
+ pub(crate) fn neg(&self, order: Ordering) {
+ self.fetch_neg(order);
+ }
+ }
+ };
+}
+
+#[cfg(target_pointer_width = "16")]
+atomic_int!(load_store_atomic, AtomicIsize, isize, 2);
+#[cfg(target_pointer_width = "16")]
+atomic_int!(load_store_atomic, AtomicUsize, usize, 2);
+#[cfg(target_pointer_width = "32")]
+atomic_int!(load_store_atomic, AtomicIsize, isize, 4);
+#[cfg(target_pointer_width = "32")]
+atomic_int!(load_store_atomic, AtomicUsize, usize, 4);
+#[cfg(target_pointer_width = "64")]
+atomic_int!(load_store_atomic, AtomicIsize, isize, 8);
+#[cfg(target_pointer_width = "64")]
+atomic_int!(load_store_atomic, AtomicUsize, usize, 8);
+#[cfg(target_pointer_width = "128")]
+atomic_int!(load_store_atomic, AtomicIsize, isize, 16);
+#[cfg(target_pointer_width = "128")]
+atomic_int!(load_store_atomic, AtomicUsize, usize, 16);
+
+atomic_int!(load_store_atomic[sub_word], AtomicI8, i8, 1);
+atomic_int!(load_store_atomic[sub_word], AtomicU8, u8, 1);
+atomic_int!(load_store_atomic[sub_word], AtomicI16, i16, 2);
+atomic_int!(load_store_atomic[sub_word], AtomicU16, u16, 2);
+
+#[cfg(not(target_pointer_width = "16"))]
+atomic_int!(load_store_atomic, AtomicI32, i32, 4);
+#[cfg(not(target_pointer_width = "16"))]
+atomic_int!(load_store_atomic, AtomicU32, u32, 4);
+#[cfg(target_pointer_width = "16")]
+#[cfg(any(test, feature = "fallback"))]
+atomic_int!(load_store_critical_session, AtomicI32, i32, 4);
+#[cfg(target_pointer_width = "16")]
+#[cfg(any(test, feature = "fallback"))]
+atomic_int!(load_store_critical_session, AtomicU32, u32, 4);
+
+#[cfg(not(any(target_pointer_width = "16", target_pointer_width = "32")))]
+atomic_int!(load_store_atomic, AtomicI64, i64, 8);
+#[cfg(not(any(target_pointer_width = "16", target_pointer_width = "32")))]
+atomic_int!(load_store_atomic, AtomicU64, u64, 8);
+#[cfg(any(target_pointer_width = "16", target_pointer_width = "32"))]
+#[cfg(any(test, feature = "fallback"))]
+atomic_int!(load_store_critical_session, AtomicI64, i64, 8);
+#[cfg(any(target_pointer_width = "16", target_pointer_width = "32"))]
+#[cfg(any(test, feature = "fallback"))]
+atomic_int!(load_store_critical_session, AtomicU64, u64, 8);
+
+#[cfg(any(test, feature = "fallback"))]
+atomic_int!(load_store_critical_session, AtomicI128, i128, 16);
+#[cfg(any(test, feature = "fallback"))]
+atomic_int!(load_store_critical_session, AtomicU128, u128, 16);
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+
+ test_atomic_ptr_single_thread!();
+ test_atomic_int_single_thread!(i8);
+ test_atomic_int_single_thread!(u8);
+ test_atomic_int_single_thread!(i16);
+ test_atomic_int_single_thread!(u16);
+ test_atomic_int_single_thread!(i32);
+ test_atomic_int_single_thread!(u32);
+ test_atomic_int_single_thread!(i64);
+ test_atomic_int_single_thread!(u64);
+ test_atomic_int_single_thread!(i128);
+ test_atomic_int_single_thread!(u128);
+ test_atomic_int_single_thread!(isize);
+ test_atomic_int_single_thread!(usize);
+}