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Diffstat (limited to 'libcore/intrinsics.rs')
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diff --git a/libcore/intrinsics.rs b/libcore/intrinsics.rs new file mode 100644 index 0000000..03bcf9c --- /dev/null +++ b/libcore/intrinsics.rs @@ -0,0 +1,623 @@ +// Copyright 2013 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or +// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +//! rustc compiler intrinsics. +//! +//! The corresponding definitions are in librustc_trans/trans/intrinsic.rs. +//! +//! # Volatiles +//! +//! The volatile intrinsics provide operations intended to act on I/O +//! memory, which are guaranteed to not be reordered by the compiler +//! across other volatile intrinsics. See the LLVM documentation on +//! [[volatile]]. +//! +//! [volatile]: http://llvm.org/docs/LangRef.html#volatile-memory-accesses +//! +//! # Atomics +//! +//! The atomic intrinsics provide common atomic operations on machine +//! words, with multiple possible memory orderings. They obey the same +//! semantics as C++11. See the LLVM documentation on [[atomics]]. +//! +//! [atomics]: http://llvm.org/docs/Atomics.html +//! +//! A quick refresher on memory ordering: +//! +//! * Acquire - a barrier for acquiring a lock. Subsequent reads and writes +//! take place after the barrier. +//! * Release - a barrier for releasing a lock. Preceding reads and writes +//! take place before the barrier. +//! * Sequentially consistent - sequentially consistent operations are +//! guaranteed to happen in order. This is the standard mode for working +//! with atomic types and is equivalent to Java's `volatile`. + +#![unstable(feature = "core_intrinsics", + reason = "intrinsics are unlikely to ever be stabilized, instead \ + they should be used through stabilized interfaces \ + in the rest of the standard library", + issue = "0")] +#![allow(missing_docs)] + +use marker::Sized; + +extern "rust-intrinsic" { + + // NB: These intrinsics take raw pointers because they mutate aliased + // memory, which is not valid for either `&` or `&mut`. + + #[cfg(all(stage0, not(cargobuild)))] + pub fn atomic_cxchg<T>(dst: *mut T, old: T, src: T) -> T; + #[cfg(all(stage0, not(cargobuild)))] + pub fn atomic_cxchg_acq<T>(dst: *mut T, old: T, src: T) -> T; + #[cfg(all(stage0, not(cargobuild)))] + pub fn atomic_cxchg_rel<T>(dst: *mut T, old: T, src: T) -> T; + #[cfg(all(stage0, not(cargobuild)))] + pub fn atomic_cxchg_acqrel<T>(dst: *mut T, old: T, src: T) -> T; + #[cfg(all(stage0, not(cargobuild)))] + pub fn atomic_cxchg_relaxed<T>(dst: *mut T, old: T, src: T) -> T; + + #[cfg(any(not(stage0), cargobuild))] + pub fn atomic_cxchg<T>(dst: *mut T, old: T, src: T) -> (T, bool); + #[cfg(any(not(stage0), cargobuild))] + pub fn atomic_cxchg_acq<T>(dst: *mut T, old: T, src: T) -> (T, bool); + #[cfg(any(not(stage0), cargobuild))] + pub fn atomic_cxchg_rel<T>(dst: *mut T, old: T, src: T) -> (T, bool); + #[cfg(any(not(stage0), cargobuild))] + pub fn atomic_cxchg_acqrel<T>(dst: *mut T, old: T, src: T) -> (T, bool); + #[cfg(any(not(stage0), cargobuild))] + pub fn atomic_cxchg_relaxed<T>(dst: *mut T, old: T, src: T) -> (T, bool); + #[cfg(any(not(stage0), cargobuild))] + pub fn atomic_cxchg_failrelaxed<T>(dst: *mut T, old: T, src: T) -> (T, bool); + #[cfg(any(not(stage0), cargobuild))] + pub fn atomic_cxchg_failacq<T>(dst: *mut T, old: T, src: T) -> (T, bool); + #[cfg(any(not(stage0), cargobuild))] + pub fn atomic_cxchg_acq_failrelaxed<T>(dst: *mut T, old: T, src: T) -> (T, bool); + #[cfg(any(not(stage0), cargobuild))] + pub fn atomic_cxchg_acqrel_failrelaxed<T>(dst: *mut T, old: T, src: T) -> (T, bool); + + pub fn atomic_cxchgweak<T>(dst: *mut T, old: T, src: T) -> (T, bool); + pub fn atomic_cxchgweak_acq<T>(dst: *mut T, old: T, src: T) -> (T, bool); + pub fn atomic_cxchgweak_rel<T>(dst: *mut T, old: T, src: T) -> (T, bool); + pub fn atomic_cxchgweak_acqrel<T>(dst: *mut T, old: T, src: T) -> (T, bool); + pub fn atomic_cxchgweak_relaxed<T>(dst: *mut T, old: T, src: T) -> (T, bool); + pub fn atomic_cxchgweak_failrelaxed<T>(dst: *mut T, old: T, src: T) -> (T, bool); + pub fn atomic_cxchgweak_failacq<T>(dst: *mut T, old: T, src: T) -> (T, bool); + pub fn atomic_cxchgweak_acq_failrelaxed<T>(dst: *mut T, old: T, src: T) -> (T, bool); + pub fn atomic_cxchgweak_acqrel_failrelaxed<T>(dst: *mut T, old: T, src: T) -> (T, bool); + + pub fn atomic_load<T>(src: *const T) -> T; + pub fn atomic_load_acq<T>(src: *const T) -> T; + pub fn atomic_load_relaxed<T>(src: *const T) -> T; + pub fn atomic_load_unordered<T>(src: *const T) -> T; + + pub fn atomic_store<T>(dst: *mut T, val: T); + pub fn atomic_store_rel<T>(dst: *mut T, val: T); + pub fn atomic_store_relaxed<T>(dst: *mut T, val: T); + pub fn atomic_store_unordered<T>(dst: *mut T, val: T); + + pub fn atomic_xchg<T>(dst: *mut T, src: T) -> T; + pub fn atomic_xchg_acq<T>(dst: *mut T, src: T) -> T; + pub fn atomic_xchg_rel<T>(dst: *mut T, src: T) -> T; + pub fn atomic_xchg_acqrel<T>(dst: *mut T, src: T) -> T; + pub fn atomic_xchg_relaxed<T>(dst: *mut T, src: T) -> T; + + pub fn atomic_xadd<T>(dst: *mut T, src: T) -> T; + pub fn atomic_xadd_acq<T>(dst: *mut T, src: T) -> T; + pub fn atomic_xadd_rel<T>(dst: *mut T, src: T) -> T; + pub fn atomic_xadd_acqrel<T>(dst: *mut T, src: T) -> T; + pub fn atomic_xadd_relaxed<T>(dst: *mut T, src: T) -> T; + + pub fn atomic_xsub<T>(dst: *mut T, src: T) -> T; + pub fn atomic_xsub_acq<T>(dst: *mut T, src: T) -> T; + pub fn atomic_xsub_rel<T>(dst: *mut T, src: T) -> T; + pub fn atomic_xsub_acqrel<T>(dst: *mut T, src: T) -> T; + pub fn atomic_xsub_relaxed<T>(dst: *mut T, src: T) -> T; + + pub fn atomic_and<T>(dst: *mut T, src: T) -> T; + pub fn atomic_and_acq<T>(dst: *mut T, src: T) -> T; + pub fn atomic_and_rel<T>(dst: *mut T, src: T) -> T; + pub fn atomic_and_acqrel<T>(dst: *mut T, src: T) -> T; + pub fn atomic_and_relaxed<T>(dst: *mut T, src: T) -> T; + + pub fn atomic_nand<T>(dst: *mut T, src: T) -> T; + pub fn atomic_nand_acq<T>(dst: *mut T, src: T) -> T; + pub fn atomic_nand_rel<T>(dst: *mut T, src: T) -> T; + pub fn atomic_nand_acqrel<T>(dst: *mut T, src: T) -> T; + pub fn atomic_nand_relaxed<T>(dst: *mut T, src: T) -> T; + + pub fn atomic_or<T>(dst: *mut T, src: T) -> T; + pub fn atomic_or_acq<T>(dst: *mut T, src: T) -> T; + pub fn atomic_or_rel<T>(dst: *mut T, src: T) -> T; + pub fn atomic_or_acqrel<T>(dst: *mut T, src: T) -> T; + pub fn atomic_or_relaxed<T>(dst: *mut T, src: T) -> T; + + pub fn atomic_xor<T>(dst: *mut T, src: T) -> T; + pub fn atomic_xor_acq<T>(dst: *mut T, src: T) -> T; + pub fn atomic_xor_rel<T>(dst: *mut T, src: T) -> T; + pub fn atomic_xor_acqrel<T>(dst: *mut T, src: T) -> T; + pub fn atomic_xor_relaxed<T>(dst: *mut T, src: T) -> T; + + pub fn atomic_max<T>(dst: *mut T, src: T) -> T; + pub fn atomic_max_acq<T>(dst: *mut T, src: T) -> T; + pub fn atomic_max_rel<T>(dst: *mut T, src: T) -> T; + pub fn atomic_max_acqrel<T>(dst: *mut T, src: T) -> T; + pub fn atomic_max_relaxed<T>(dst: *mut T, src: T) -> T; + + pub fn atomic_min<T>(dst: *mut T, src: T) -> T; + pub fn atomic_min_acq<T>(dst: *mut T, src: T) -> T; + pub fn atomic_min_rel<T>(dst: *mut T, src: T) -> T; + pub fn atomic_min_acqrel<T>(dst: *mut T, src: T) -> T; + pub fn atomic_min_relaxed<T>(dst: *mut T, src: T) -> T; + + pub fn atomic_umin<T>(dst: *mut T, src: T) -> T; + pub fn atomic_umin_acq<T>(dst: *mut T, src: T) -> T; + pub fn atomic_umin_rel<T>(dst: *mut T, src: T) -> T; + pub fn atomic_umin_acqrel<T>(dst: *mut T, src: T) -> T; + pub fn atomic_umin_relaxed<T>(dst: *mut T, src: T) -> T; + + pub fn atomic_umax<T>(dst: *mut T, src: T) -> T; + pub fn atomic_umax_acq<T>(dst: *mut T, src: T) -> T; + pub fn atomic_umax_rel<T>(dst: *mut T, src: T) -> T; + pub fn atomic_umax_acqrel<T>(dst: *mut T, src: T) -> T; + pub fn atomic_umax_relaxed<T>(dst: *mut T, src: T) -> T; +} + +extern "rust-intrinsic" { + + pub fn atomic_fence(); + pub fn atomic_fence_acq(); + pub fn atomic_fence_rel(); + pub fn atomic_fence_acqrel(); + + /// A compiler-only memory barrier. + /// + /// Memory accesses will never be reordered across this barrier by the + /// compiler, but no instructions will be emitted for it. This is + /// appropriate for operations on the same thread that may be preempted, + /// such as when interacting with signal handlers. + pub fn atomic_singlethreadfence(); + pub fn atomic_singlethreadfence_acq(); + pub fn atomic_singlethreadfence_rel(); + pub fn atomic_singlethreadfence_acqrel(); + + /// Aborts the execution of the process. + pub fn abort() -> !; + + /// Tells LLVM that this point in the code is not reachable, + /// enabling further optimizations. + /// + /// NB: This is very different from the `unreachable!()` macro! + pub fn unreachable() -> !; + + /// Informs the optimizer that a condition is always true. + /// If the condition is false, the behavior is undefined. + /// + /// No code is generated for this intrinsic, but the optimizer will try + /// to preserve it (and its condition) between passes, which may interfere + /// with optimization of surrounding code and reduce performance. It should + /// not be used if the invariant can be discovered by the optimizer on its + /// own, or if it does not enable any significant optimizations. + pub fn assume(b: bool); + + /// Executes a breakpoint trap, for inspection by a debugger. + pub fn breakpoint(); + + /// The size of a type in bytes. + /// + /// This is the exact number of bytes in memory taken up by a + /// value of the given type. In other words, a memset of this size + /// would *exactly* overwrite a value. When laid out in vectors + /// and structures there may be additional padding between + /// elements. + pub fn size_of<T>() -> usize; + + /// Moves a value to an uninitialized memory location. + /// + /// Drop glue is not run on the destination. + pub fn move_val_init<T>(dst: *mut T, src: T); + + pub fn min_align_of<T>() -> usize; + pub fn pref_align_of<T>() -> usize; + + pub fn size_of_val<T: ?Sized>(_: &T) -> usize; + pub fn min_align_of_val<T: ?Sized>(_: &T) -> usize; + + /// Executes the destructor (if any) of the pointed-to value. + /// + /// This has two use cases: + /// + /// * It is *required* to use `drop_in_place` to drop unsized types like + /// trait objects, because they can't be read out onto the stack and + /// dropped normally. + /// + /// * It is friendlier to the optimizer to do this over `ptr::read` when + /// dropping manually allocated memory (e.g. when writing Box/Rc/Vec), + /// as the compiler doesn't need to prove that it's sound to elide the + /// copy. + /// + /// # Undefined Behavior + /// + /// This has all the same safety problems as `ptr::read` with respect to + /// invalid pointers, types, and double drops. + #[stable(feature = "drop_in_place", since = "1.8.0")] + pub fn drop_in_place<T: ?Sized>(to_drop: *mut T); + + /// Gets a static string slice containing the name of a type. + pub fn type_name<T: ?Sized>() -> &'static str; + + /// Gets an identifier which is globally unique to the specified type. This + /// function will return the same value for a type regardless of whichever + /// crate it is invoked in. + pub fn type_id<T: ?Sized + 'static>() -> u64; + + /// Creates a value initialized to so that its drop flag, + /// if any, says that it has been dropped. + /// + /// `init_dropped` is unsafe because it returns a datum with all + /// of its bytes set to the drop flag, which generally does not + /// correspond to a valid value. + /// + /// This intrinsic is likely to be deprecated in the future when + /// Rust moves to non-zeroing dynamic drop (and thus removes the + /// embedded drop flags that are being established by this + /// intrinsic). + pub fn init_dropped<T>() -> T; + + /// Creates a value initialized to zero. + /// + /// `init` is unsafe because it returns a zeroed-out datum, + /// which is unsafe unless T is `Copy`. Also, even if T is + /// `Copy`, an all-zero value may not correspond to any legitimate + /// state for the type in question. + pub fn init<T>() -> T; + + /// Creates an uninitialized value. + /// + /// `uninit` is unsafe because there is no guarantee of what its + /// contents are. In particular its drop-flag may be set to any + /// state, which means it may claim either dropped or + /// undropped. In the general case one must use `ptr::write` to + /// initialize memory previous set to the result of `uninit`. + pub fn uninit<T>() -> T; + + /// Moves a value out of scope without running drop glue. + pub fn forget<T>(_: T) -> (); + + /// Unsafely transforms a value of one type into a value of another type. + /// + /// Both types must have the same size. + /// + /// # Examples + /// + /// ``` + /// use std::mem; + /// + /// let array: &[u8] = unsafe { mem::transmute("Rust") }; + /// assert_eq!(array, [82, 117, 115, 116]); + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + pub fn transmute<T, U>(e: T) -> U; + + /// Gives the address for the return value of the enclosing function. + /// + /// Using this intrinsic in a function that does not use an out pointer + /// will trigger a compiler error. + pub fn return_address() -> *const u8; + + /// Returns `true` if the actual type given as `T` requires drop + /// glue; returns `false` if the actual type provided for `T` + /// implements `Copy`. + /// + /// If the actual type neither requires drop glue nor implements + /// `Copy`, then may return `true` or `false`. + pub fn needs_drop<T>() -> bool; + + /// Calculates the offset from a pointer. + /// + /// This is implemented as an intrinsic to avoid converting to and from an + /// integer, since the conversion would throw away aliasing information. + /// + /// # Safety + /// + /// Both the starting and resulting pointer must be either in bounds or one + /// byte past the end of an allocated object. If either pointer is out of + /// bounds or arithmetic overflow occurs then any further use of the + /// returned value will result in undefined behavior. + pub fn offset<T>(dst: *const T, offset: isize) -> *const T; + + /// Calculates the offset from a pointer, potentially wrapping. + /// + /// This is implemented as an intrinsic to avoid converting to and from an + /// integer, since the conversion inhibits certain optimizations. + /// + /// # Safety + /// + /// Unlike the `offset` intrinsic, this intrinsic does not restrict the + /// resulting pointer to point into or one byte past the end of an allocated + /// object, and it wraps with two's complement arithmetic. The resulting + /// value is not necessarily valid to be used to actually access memory. + pub fn arith_offset<T>(dst: *const T, offset: isize) -> *const T; + + /// Copies `count * size_of<T>` bytes from `src` to `dst`. The source + /// and destination may *not* overlap. + /// + /// `copy_nonoverlapping` is semantically equivalent to C's `memcpy`. + /// + /// # Safety + /// + /// Beyond requiring that the program must be allowed to access both regions + /// of memory, it is Undefined Behavior for source and destination to + /// overlap. Care must also be taken with the ownership of `src` and + /// `dst`. This method semantically moves the values of `src` into `dst`. + /// However it does not drop the contents of `dst`, or prevent the contents + /// of `src` from being dropped or used. + /// + /// # Examples + /// + /// A safe swap function: + /// + /// ``` + /// use std::mem; + /// use std::ptr; + /// + /// # #[allow(dead_code)] + /// fn swap<T>(x: &mut T, y: &mut T) { + /// unsafe { + /// // Give ourselves some scratch space to work with + /// let mut t: T = mem::uninitialized(); + /// + /// // Perform the swap, `&mut` pointers never alias + /// ptr::copy_nonoverlapping(x, &mut t, 1); + /// ptr::copy_nonoverlapping(y, x, 1); + /// ptr::copy_nonoverlapping(&t, y, 1); + /// + /// // y and t now point to the same thing, but we need to completely forget `tmp` + /// // because it's no longer relevant. + /// mem::forget(t); + /// } + /// } + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + pub fn copy_nonoverlapping<T>(src: *const T, dst: *mut T, count: usize); + + /// Copies `count * size_of<T>` bytes from `src` to `dst`. The source + /// and destination may overlap. + /// + /// `copy` is semantically equivalent to C's `memmove`. + /// + /// # Safety + /// + /// Care must be taken with the ownership of `src` and `dst`. + /// This method semantically moves the values of `src` into `dst`. + /// However it does not drop the contents of `dst`, or prevent the contents of `src` + /// from being dropped or used. + /// + /// # Examples + /// + /// Efficiently create a Rust vector from an unsafe buffer: + /// + /// ``` + /// use std::ptr; + /// + /// # #[allow(dead_code)] + /// unsafe fn from_buf_raw<T>(ptr: *const T, elts: usize) -> Vec<T> { + /// let mut dst = Vec::with_capacity(elts); + /// dst.set_len(elts); + /// ptr::copy(ptr, dst.as_mut_ptr(), elts); + /// dst + /// } + /// ``` + /// + #[stable(feature = "rust1", since = "1.0.0")] + pub fn copy<T>(src: *const T, dst: *mut T, count: usize); + + /// Invokes memset on the specified pointer, setting `count * size_of::<T>()` + /// bytes of memory starting at `dst` to `val`. + #[stable(feature = "rust1", since = "1.0.0")] + pub fn write_bytes<T>(dst: *mut T, val: u8, count: usize); + + /// Equivalent to the appropriate `llvm.memcpy.p0i8.0i8.*` intrinsic, with + /// a size of `count` * `size_of::<T>()` and an alignment of + /// `min_align_of::<T>()` + /// + /// The volatile parameter is set to `true`, so it will not be optimized out. + pub fn volatile_copy_nonoverlapping_memory<T>(dst: *mut T, src: *const T, + count: usize); + /// Equivalent to the appropriate `llvm.memmove.p0i8.0i8.*` intrinsic, with + /// a size of `count` * `size_of::<T>()` and an alignment of + /// `min_align_of::<T>()` + /// + /// The volatile parameter is set to `true`, so it will not be optimized out. + pub fn volatile_copy_memory<T>(dst: *mut T, src: *const T, count: usize); + /// Equivalent to the appropriate `llvm.memset.p0i8.*` intrinsic, with a + /// size of `count` * `size_of::<T>()` and an alignment of + /// `min_align_of::<T>()`. + /// + /// The volatile parameter is set to `true`, so it will not be optimized out. + pub fn volatile_set_memory<T>(dst: *mut T, val: u8, count: usize); + + /// Perform a volatile load from the `src` pointer. + pub fn volatile_load<T>(src: *const T) -> T; + /// Perform a volatile store to the `dst` pointer. + pub fn volatile_store<T>(dst: *mut T, val: T); + + /// Returns the square root of an `f32` + pub fn sqrtf32(x: f32) -> f32; + /// Returns the square root of an `f64` + pub fn sqrtf64(x: f64) -> f64; + + /// Raises an `f32` to an integer power. + pub fn powif32(a: f32, x: i32) -> f32; + /// Raises an `f64` to an integer power. + pub fn powif64(a: f64, x: i32) -> f64; + + /// Returns the sine of an `f32`. + pub fn sinf32(x: f32) -> f32; + /// Returns the sine of an `f64`. + pub fn sinf64(x: f64) -> f64; + + /// Returns the cosine of an `f32`. + pub fn cosf32(x: f32) -> f32; + /// Returns the cosine of an `f64`. + pub fn cosf64(x: f64) -> f64; + + /// Raises an `f32` to an `f32` power. + pub fn powf32(a: f32, x: f32) -> f32; + /// Raises an `f64` to an `f64` power. + pub fn powf64(a: f64, x: f64) -> f64; + + /// Returns the exponential of an `f32`. + pub fn expf32(x: f32) -> f32; + /// Returns the exponential of an `f64`. + pub fn expf64(x: f64) -> f64; + + /// Returns 2 raised to the power of an `f32`. + pub fn exp2f32(x: f32) -> f32; + /// Returns 2 raised to the power of an `f64`. + pub fn exp2f64(x: f64) -> f64; + + /// Returns the natural logarithm of an `f32`. + pub fn logf32(x: f32) -> f32; + /// Returns the natural logarithm of an `f64`. + pub fn logf64(x: f64) -> f64; + + /// Returns the base 10 logarithm of an `f32`. + pub fn log10f32(x: f32) -> f32; + /// Returns the base 10 logarithm of an `f64`. + pub fn log10f64(x: f64) -> f64; + + /// Returns the base 2 logarithm of an `f32`. + pub fn log2f32(x: f32) -> f32; + /// Returns the base 2 logarithm of an `f64`. + pub fn log2f64(x: f64) -> f64; + + /// Returns `a * b + c` for `f32` values. + pub fn fmaf32(a: f32, b: f32, c: f32) -> f32; + /// Returns `a * b + c` for `f64` values. + pub fn fmaf64(a: f64, b: f64, c: f64) -> f64; + + /// Returns the absolute value of an `f32`. + pub fn fabsf32(x: f32) -> f32; + /// Returns the absolute value of an `f64`. + pub fn fabsf64(x: f64) -> f64; + + /// Copies the sign from `y` to `x` for `f32` values. + pub fn copysignf32(x: f32, y: f32) -> f32; + /// Copies the sign from `y` to `x` for `f64` values. + pub fn copysignf64(x: f64, y: f64) -> f64; + + /// Returns the largest integer less than or equal to an `f32`. + pub fn floorf32(x: f32) -> f32; + /// Returns the largest integer less than or equal to an `f64`. + pub fn floorf64(x: f64) -> f64; + + /// Returns the smallest integer greater than or equal to an `f32`. + pub fn ceilf32(x: f32) -> f32; + /// Returns the smallest integer greater than or equal to an `f64`. + pub fn ceilf64(x: f64) -> f64; + + /// Returns the integer part of an `f32`. + pub fn truncf32(x: f32) -> f32; + /// Returns the integer part of an `f64`. + pub fn truncf64(x: f64) -> f64; + + /// Returns the nearest integer to an `f32`. May raise an inexact floating-point exception + /// if the argument is not an integer. + pub fn rintf32(x: f32) -> f32; + /// Returns the nearest integer to an `f64`. May raise an inexact floating-point exception + /// if the argument is not an integer. + pub fn rintf64(x: f64) -> f64; + + /// Returns the nearest integer to an `f32`. + pub fn nearbyintf32(x: f32) -> f32; + /// Returns the nearest integer to an `f64`. + pub fn nearbyintf64(x: f64) -> f64; + + /// Returns the nearest integer to an `f32`. Rounds half-way cases away from zero. + pub fn roundf32(x: f32) -> f32; + /// Returns the nearest integer to an `f64`. Rounds half-way cases away from zero. + pub fn roundf64(x: f64) -> f64; + + /// Float addition that allows optimizations based on algebraic rules. + /// May assume inputs are finite. + #[cfg(not(stage0))] + pub fn fadd_fast<T>(a: T, b: T) -> T; + + /// Float subtraction that allows optimizations based on algebraic rules. + /// May assume inputs are finite. + #[cfg(not(stage0))] + pub fn fsub_fast<T>(a: T, b: T) -> T; + + /// Float multiplication that allows optimizations based on algebraic rules. + /// May assume inputs are finite. + #[cfg(not(stage0))] + pub fn fmul_fast<T>(a: T, b: T) -> T; + + /// Float division that allows optimizations based on algebraic rules. + /// May assume inputs are finite. + #[cfg(not(stage0))] + pub fn fdiv_fast<T>(a: T, b: T) -> T; + + /// Float remainder that allows optimizations based on algebraic rules. + /// May assume inputs are finite. + #[cfg(not(stage0))] + pub fn frem_fast<T>(a: T, b: T) -> T; + + + /// Returns the number of bits set in an integer type `T` + pub fn ctpop<T>(x: T) -> T; + + /// Returns the number of leading bits unset in an integer type `T` + pub fn ctlz<T>(x: T) -> T; + + /// Returns the number of trailing bits unset in an integer type `T` + pub fn cttz<T>(x: T) -> T; + + /// Reverses the bytes in an integer type `T`. + pub fn bswap<T>(x: T) -> T; + + /// Performs checked integer addition. + pub fn add_with_overflow<T>(x: T, y: T) -> (T, bool); + + /// Performs checked integer subtraction + pub fn sub_with_overflow<T>(x: T, y: T) -> (T, bool); + + /// Performs checked integer multiplication + pub fn mul_with_overflow<T>(x: T, y: T) -> (T, bool); + + /// Performs an unchecked division, resulting in undefined behavior + /// where y = 0 or x = `T::min_value()` and y = -1 + pub fn unchecked_div<T>(x: T, y: T) -> T; + /// Returns the remainder of an unchecked division, resulting in + /// undefined behavior where y = 0 or x = `T::min_value()` and y = -1 + pub fn unchecked_rem<T>(x: T, y: T) -> T; + + /// Returns (a + b) mod 2^N, where N is the width of T in bits. + pub fn overflowing_add<T>(a: T, b: T) -> T; + /// Returns (a - b) mod 2^N, where N is the width of T in bits. + pub fn overflowing_sub<T>(a: T, b: T) -> T; + /// Returns (a * b) mod 2^N, where N is the width of T in bits. + pub fn overflowing_mul<T>(a: T, b: T) -> T; + + /// Returns the value of the discriminant for the variant in 'v', + /// cast to a `u64`; if `T` has no discriminant, returns 0. + pub fn discriminant_value<T>(v: &T) -> u64; + + /// Rust's "try catch" construct which invokes the function pointer `f` with + /// the data pointer `data`. + /// + /// The third pointer is a target-specific data pointer which is filled in + /// with the specifics of the exception that occurred. For examples on Unix + /// platforms this is a `*mut *mut T` which is filled in by the compiler and + /// on MSVC it's `*mut [usize; 2]`. For more information see the compiler's + /// source as well as std's catch implementation. + pub fn try(f: fn(*mut u8), data: *mut u8, local_ptr: *mut u8) -> i32; +} |