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//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2020 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
import Swift
/// A pointer for accessing "volatile" memory, e.g. memory-mapped I/O registers.
///
/// Do not use for inter-thread synchronization. This is only meaningful for
/// low-level operations on special memory addresses performed from OS kernels,
/// embedded firmware, and similar environments.
///
/// The semantics of volatile load and volatile store operations match the LLVM
/// volatile semantics. Notably, a volatile operation cannot be added, removed,
/// or reordered with other volatile operations by the compiler. They may be
/// reordered with non-volatile operations. For details, see
/// <https://llvm.org/docs/LangRef.html#volatile-memory-accesses>.
@frozen
public struct VolatileMappedRegister<Pointee> {
@usableFromInline
let _rawPointer: Builtin.RawPointer
@_transparent
@unsafe
public init(unsafeBitPattern: UInt) {
self._rawPointer = Builtin.inttoptr_Word(unsafeBitPattern._builtinWordValue)
}
}
extension VolatileMappedRegister where Pointee == UInt8 {
/// Perform an 8-bit volatile load operation from the target pointer.
///
/// Do not use for inter-thread synchronization.
@_transparent
public func load() -> Pointee {
UInt8(Builtin.atomicload_monotonic_volatile_Int8(_rawPointer))
}
/// Perform an 8-bit volatile store operation on the target pointer.
///
/// Do not use for inter-thread synchronization.
@_transparent
public func store(_ value: Pointee) {
Builtin.atomicstore_monotonic_volatile_Int8(_rawPointer, value._value)
}
}
extension VolatileMappedRegister where Pointee == UInt16 {
/// Perform a 16-bit volatile load operation from the target pointer.
///
/// Do not use for inter-thread synchronization.
@_transparent
public func load() -> Pointee {
UInt16(Builtin.atomicload_monotonic_volatile_Int16(_rawPointer))
}
/// Perform a 16-bit volatile store operation on the target pointer.
///
/// Do not use for inter-thread synchronization.
@_transparent
public func store(_ value: Pointee) {
Builtin.atomicstore_monotonic_volatile_Int16(_rawPointer, value._value)
}
}
extension VolatileMappedRegister where Pointee == UInt32 {
/// Perform a 32-bit volatile load operation from the target pointer.
///
/// Do not use for inter-thread synchronization.
@_transparent
public func load() -> Pointee {
UInt32(Builtin.atomicload_monotonic_volatile_Int32(_rawPointer))
}
/// Perform a 32-bit volatile store operation on the target pointer.
///
/// Do not use for inter-thread synchronization.
@_transparent
public func store(_ value: Pointee) {
Builtin.atomicstore_monotonic_volatile_Int32(_rawPointer, value._value)
}
}
extension VolatileMappedRegister where Pointee == UInt64 {
/// Perform a 64-bit volatile load operation from the target pointer.
///
/// Do not use for inter-thread synchronization.
@_transparent
public func load() -> Pointee {
UInt64(Builtin.atomicload_monotonic_volatile_Int64(_rawPointer))
}
/// Perform a 64-bit volatile store operation on the target pointer.
///
/// Do not use for inter-thread synchronization.
@_transparent
public func store(_ value: Pointee) {
Builtin.atomicstore_monotonic_volatile_Int64(_rawPointer, value._value)
}
}
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