1 // Copyright 2013 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! rustc compiler intrinsics.
13 //! The corresponding definitions are in librustc_trans/trans/intrinsic.rs.
17 //! The volatile intrinsics provide operations intended to act on I/O
18 //! memory, which are guaranteed to not be reordered by the compiler
19 //! across other volatile intrinsics. See the LLVM documentation on
22 //! [volatile]: http://llvm.org/docs/LangRef.html#volatile-memory-accesses
26 //! The atomic intrinsics provide common atomic operations on machine
27 //! words, with multiple possible memory orderings. They obey the same
28 //! semantics as C++11. See the LLVM documentation on [[atomics]].
30 //! [atomics]: http://llvm.org/docs/Atomics.html
32 //! A quick refresher on memory ordering:
34 //! * Acquire - a barrier for acquiring a lock. Subsequent reads and writes
35 //! take place after the barrier.
36 //! * Release - a barrier for releasing a lock. Preceding reads and writes
37 //! take place before the barrier.
38 //! * Sequentially consistent - sequentially consistent operations are
39 //! guaranteed to happen in order. This is the standard mode for working
40 //! with atomic types and is equivalent to Java's `volatile`.
42 #![unstable(feature = "core_intrinsics",
43 reason = "intrinsics are unlikely to ever be stabilized, instead \
44 they should be used through stabilized interfaces \
45 in the rest of the standard library",
47 #![allow(missing_docs)]
51 extern "rust-intrinsic" {
53 // NB: These intrinsics take raw pointers because they mutate aliased
54 // memory, which is not valid for either `&` or `&mut`.
56 pub fn atomic_cxchg<T>(dst: *mut T, old: T, src: T) -> T;
57 pub fn atomic_cxchg_acq<T>(dst: *mut T, old: T, src: T) -> T;
58 pub fn atomic_cxchg_rel<T>(dst: *mut T, old: T, src: T) -> T;
59 pub fn atomic_cxchg_acqrel<T>(dst: *mut T, old: T, src: T) -> T;
60 pub fn atomic_cxchg_relaxed<T>(dst: *mut T, old: T, src: T) -> T;
62 pub fn atomic_load<T>(src: *const T) -> T;
63 pub fn atomic_load_acq<T>(src: *const T) -> T;
64 pub fn atomic_load_relaxed<T>(src: *const T) -> T;
65 pub fn atomic_load_unordered<T>(src: *const T) -> T;
67 pub fn atomic_store<T>(dst: *mut T, val: T);
68 pub fn atomic_store_rel<T>(dst: *mut T, val: T);
69 pub fn atomic_store_relaxed<T>(dst: *mut T, val: T);
70 pub fn atomic_store_unordered<T>(dst: *mut T, val: T);
72 pub fn atomic_xchg<T>(dst: *mut T, src: T) -> T;
73 pub fn atomic_xchg_acq<T>(dst: *mut T, src: T) -> T;
74 pub fn atomic_xchg_rel<T>(dst: *mut T, src: T) -> T;
75 pub fn atomic_xchg_acqrel<T>(dst: *mut T, src: T) -> T;
76 pub fn atomic_xchg_relaxed<T>(dst: *mut T, src: T) -> T;
78 pub fn atomic_xadd<T>(dst: *mut T, src: T) -> T;
79 pub fn atomic_xadd_acq<T>(dst: *mut T, src: T) -> T;
80 pub fn atomic_xadd_rel<T>(dst: *mut T, src: T) -> T;
81 pub fn atomic_xadd_acqrel<T>(dst: *mut T, src: T) -> T;
82 pub fn atomic_xadd_relaxed<T>(dst: *mut T, src: T) -> T;
84 pub fn atomic_xsub<T>(dst: *mut T, src: T) -> T;
85 pub fn atomic_xsub_acq<T>(dst: *mut T, src: T) -> T;
86 pub fn atomic_xsub_rel<T>(dst: *mut T, src: T) -> T;
87 pub fn atomic_xsub_acqrel<T>(dst: *mut T, src: T) -> T;
88 pub fn atomic_xsub_relaxed<T>(dst: *mut T, src: T) -> T;
90 pub fn atomic_and<T>(dst: *mut T, src: T) -> T;
91 pub fn atomic_and_acq<T>(dst: *mut T, src: T) -> T;
92 pub fn atomic_and_rel<T>(dst: *mut T, src: T) -> T;
93 pub fn atomic_and_acqrel<T>(dst: *mut T, src: T) -> T;
94 pub fn atomic_and_relaxed<T>(dst: *mut T, src: T) -> T;
96 pub fn atomic_nand<T>(dst: *mut T, src: T) -> T;
97 pub fn atomic_nand_acq<T>(dst: *mut T, src: T) -> T;
98 pub fn atomic_nand_rel<T>(dst: *mut T, src: T) -> T;
99 pub fn atomic_nand_acqrel<T>(dst: *mut T, src: T) -> T;
100 pub fn atomic_nand_relaxed<T>(dst: *mut T, src: T) -> T;
102 pub fn atomic_or<T>(dst: *mut T, src: T) -> T;
103 pub fn atomic_or_acq<T>(dst: *mut T, src: T) -> T;
104 pub fn atomic_or_rel<T>(dst: *mut T, src: T) -> T;
105 pub fn atomic_or_acqrel<T>(dst: *mut T, src: T) -> T;
106 pub fn atomic_or_relaxed<T>(dst: *mut T, src: T) -> T;
108 pub fn atomic_xor<T>(dst: *mut T, src: T) -> T;
109 pub fn atomic_xor_acq<T>(dst: *mut T, src: T) -> T;
110 pub fn atomic_xor_rel<T>(dst: *mut T, src: T) -> T;
111 pub fn atomic_xor_acqrel<T>(dst: *mut T, src: T) -> T;
112 pub fn atomic_xor_relaxed<T>(dst: *mut T, src: T) -> T;
114 pub fn atomic_max<T>(dst: *mut T, src: T) -> T;
115 pub fn atomic_max_acq<T>(dst: *mut T, src: T) -> T;
116 pub fn atomic_max_rel<T>(dst: *mut T, src: T) -> T;
117 pub fn atomic_max_acqrel<T>(dst: *mut T, src: T) -> T;
118 pub fn atomic_max_relaxed<T>(dst: *mut T, src: T) -> T;
120 pub fn atomic_min<T>(dst: *mut T, src: T) -> T;
121 pub fn atomic_min_acq<T>(dst: *mut T, src: T) -> T;
122 pub fn atomic_min_rel<T>(dst: *mut T, src: T) -> T;
123 pub fn atomic_min_acqrel<T>(dst: *mut T, src: T) -> T;
124 pub fn atomic_min_relaxed<T>(dst: *mut T, src: T) -> T;
126 pub fn atomic_umin<T>(dst: *mut T, src: T) -> T;
127 pub fn atomic_umin_acq<T>(dst: *mut T, src: T) -> T;
128 pub fn atomic_umin_rel<T>(dst: *mut T, src: T) -> T;
129 pub fn atomic_umin_acqrel<T>(dst: *mut T, src: T) -> T;
130 pub fn atomic_umin_relaxed<T>(dst: *mut T, src: T) -> T;
132 pub fn atomic_umax<T>(dst: *mut T, src: T) -> T;
133 pub fn atomic_umax_acq<T>(dst: *mut T, src: T) -> T;
134 pub fn atomic_umax_rel<T>(dst: *mut T, src: T) -> T;
135 pub fn atomic_umax_acqrel<T>(dst: *mut T, src: T) -> T;
136 pub fn atomic_umax_relaxed<T>(dst: *mut T, src: T) -> T;
139 extern "rust-intrinsic" {
141 pub fn atomic_fence();
142 pub fn atomic_fence_acq();
143 pub fn atomic_fence_rel();
144 pub fn atomic_fence_acqrel();
146 /// A compiler-only memory barrier.
148 /// Memory accesses will never be reordered across this barrier by the
149 /// compiler, but no instructions will be emitted for it. This is
150 /// appropriate for operations on the same thread that may be preempted,
151 /// such as when interacting with signal handlers.
152 pub fn atomic_singlethreadfence();
153 pub fn atomic_singlethreadfence_acq();
154 pub fn atomic_singlethreadfence_rel();
155 pub fn atomic_singlethreadfence_acqrel();
157 /// Aborts the execution of the process.
160 /// Tells LLVM that this point in the code is not reachable,
161 /// enabling further optimizations.
163 /// NB: This is very different from the `unreachable!()` macro!
164 pub fn unreachable() -> !;
166 /// Informs the optimizer that a condition is always true.
167 /// If the condition is false, the behavior is undefined.
169 /// No code is generated for this intrinsic, but the optimizer will try
170 /// to preserve it (and its condition) between passes, which may interfere
171 /// with optimization of surrounding code and reduce performance. It should
172 /// not be used if the invariant can be discovered by the optimizer on its
173 /// own, or if it does not enable any significant optimizations.
174 pub fn assume(b: bool);
176 /// Executes a breakpoint trap, for inspection by a debugger.
179 /// The size of a type in bytes.
181 /// This is the exact number of bytes in memory taken up by a
182 /// value of the given type. In other words, a memset of this size
183 /// would *exactly* overwrite a value. When laid out in vectors
184 /// and structures there may be additional padding between
186 pub fn size_of<T>() -> usize;
188 /// Moves a value to an uninitialized memory location.
190 /// Drop glue is not run on the destination.
191 pub fn move_val_init<T>(dst: *mut T, src: T);
193 pub fn min_align_of<T>() -> usize;
194 pub fn pref_align_of<T>() -> usize;
196 pub fn size_of_val<T: ?Sized>(_: &T) -> usize;
197 pub fn min_align_of_val<T: ?Sized>(_: &T) -> usize;
199 /// Executes the destructor (if any) of the pointed-to value.
201 /// This has two use cases:
203 /// * It is *required* to use `drop_in_place` to drop unsized types like
204 /// trait objects, because they can't be read out onto the stack and
205 /// dropped normally.
207 /// * It is friendlier to the optimizer to do this over `ptr::read` when
208 /// dropping manually allocated memory (e.g. when writing Box/Rc/Vec),
209 /// as the compiler doesn't need to prove that it's sound to elide the
212 /// # Undefined Behavior
214 /// This has all the same safety problems as `ptr::read` with respect to
215 /// invalid pointers, types, and double drops.
216 #[unstable(feature = "drop_in_place", reason = "just exposed, needs FCP", issue = "27908")]
217 pub fn drop_in_place<T: ?Sized>(to_drop: *mut T);
219 /// Gets a static string slice containing the name of a type.
220 pub fn type_name<T: ?Sized>() -> &'static str;
222 /// Gets an identifier which is globally unique to the specified type. This
223 /// function will return the same value for a type regardless of whichever
224 /// crate it is invoked in.
225 pub fn type_id<T: ?Sized + 'static>() -> u64;
227 /// Creates a value initialized to so that its drop flag,
228 /// if any, says that it has been dropped.
230 /// `init_dropped` is unsafe because it returns a datum with all
231 /// of its bytes set to the drop flag, which generally does not
232 /// correspond to a valid value.
234 /// This intrinsic is likely to be deprecated in the future when
235 /// Rust moves to non-zeroing dynamic drop (and thus removes the
236 /// embedded drop flags that are being established by this
238 pub fn init_dropped<T>() -> T;
240 /// Creates a value initialized to zero.
242 /// `init` is unsafe because it returns a zeroed-out datum,
243 /// which is unsafe unless T is `Copy`. Also, even if T is
244 /// `Copy`, an all-zero value may not correspond to any legitimate
245 /// state for the type in question.
246 pub fn init<T>() -> T;
248 /// Creates an uninitialized value.
250 /// `uninit` is unsafe because there is no guarantee of what its
251 /// contents are. In particular its drop-flag may be set to any
252 /// state, which means it may claim either dropped or
253 /// undropped. In the general case one must use `ptr::write` to
254 /// initialize memory previous set to the result of `uninit`.
255 pub fn uninit<T>() -> T;
257 /// Moves a value out of scope without running drop glue.
258 pub fn forget<T>(_: T) -> ();
260 /// Unsafely transforms a value of one type into a value of another type.
262 /// Both types must have the same size.
269 /// let array: &[u8] = unsafe { mem::transmute("Rust") };
270 /// assert_eq!(array, [82, 117, 115, 116]);
272 #[stable(feature = "rust1", since = "1.0.0")]
273 pub fn transmute<T, U>(e: T) -> U;
275 /// Gives the address for the return value of the enclosing function.
277 /// Using this intrinsic in a function that does not use an out pointer
278 /// will trigger a compiler error.
279 pub fn return_address() -> *const u8;
281 /// Returns `true` if the actual type given as `T` requires drop
282 /// glue; returns `false` if the actual type provided for `T`
283 /// implements `Copy`.
285 /// If the actual type neither requires drop glue nor implements
286 /// `Copy`, then may return `true` or `false`.
287 pub fn needs_drop<T>() -> bool;
289 /// Calculates the offset from a pointer.
291 /// This is implemented as an intrinsic to avoid converting to and from an
292 /// integer, since the conversion would throw away aliasing information.
296 /// Both the starting and resulting pointer must be either in bounds or one
297 /// byte past the end of an allocated object. If either pointer is out of
298 /// bounds or arithmetic overflow occurs then any further use of the
299 /// returned value will result in undefined behavior.
300 pub fn offset<T>(dst: *const T, offset: isize) -> *const T;
302 /// Calculates the offset from a pointer, potentially wrapping.
304 /// This is implemented as an intrinsic to avoid converting to and from an
305 /// integer, since the conversion inhibits certain optimizations.
309 /// Unlike the `offset` intrinsic, this intrinsic does not restrict the
310 /// resulting pointer to point into or one byte past the end of an allocated
311 /// object, and it wraps with two's complement arithmetic. The resulting
312 /// value is not necessarily valid to be used to actually access memory.
313 pub fn arith_offset<T>(dst: *const T, offset: isize) -> *const T;
315 /// Copies `count * size_of<T>` bytes from `src` to `dst`. The source
316 /// and destination may *not* overlap.
318 /// `copy_nonoverlapping` is semantically equivalent to C's `memcpy`.
322 /// Beyond requiring that the program must be allowed to access both regions
323 /// of memory, it is Undefined Behavior for source and destination to
324 /// overlap. Care must also be taken with the ownership of `src` and
325 /// `dst`. This method semantically moves the values of `src` into `dst`.
326 /// However it does not drop the contents of `dst`, or prevent the contents
327 /// of `src` from being dropped or used.
331 /// A safe swap function:
337 /// fn swap<T>(x: &mut T, y: &mut T) {
339 /// // Give ourselves some scratch space to work with
340 /// let mut t: T = mem::uninitialized();
342 /// // Perform the swap, `&mut` pointers never alias
343 /// ptr::copy_nonoverlapping(x, &mut t, 1);
344 /// ptr::copy_nonoverlapping(y, x, 1);
345 /// ptr::copy_nonoverlapping(&t, y, 1);
347 /// // y and t now point to the same thing, but we need to completely forget `tmp`
348 /// // because it's no longer relevant.
353 #[stable(feature = "rust1", since = "1.0.0")]
354 pub fn copy_nonoverlapping<T>(src: *const T, dst: *mut T, count: usize);
356 /// Copies `count * size_of<T>` bytes from `src` to `dst`. The source
357 /// and destination may overlap.
359 /// `copy` is semantically equivalent to C's `memmove`.
363 /// Care must be taken with the ownership of `src` and `dst`.
364 /// This method semantically moves the values of `src` into `dst`.
365 /// However it does not drop the contents of `dst`, or prevent the contents of `src`
366 /// from being dropped or used.
370 /// Efficiently create a Rust vector from an unsafe buffer:
375 /// unsafe fn from_buf_raw<T>(ptr: *const T, elts: usize) -> Vec<T> {
376 /// let mut dst = Vec::with_capacity(elts);
377 /// dst.set_len(elts);
378 /// ptr::copy(ptr, dst.as_mut_ptr(), elts);
383 #[stable(feature = "rust1", since = "1.0.0")]
384 pub fn copy<T>(src: *const T, dst: *mut T, count: usize);
386 /// Invokes memset on the specified pointer, setting `count * size_of::<T>()`
387 /// bytes of memory starting at `dst` to `c`.
388 #[stable(feature = "rust1", since = "1.0.0")]
389 pub fn write_bytes<T>(dst: *mut T, val: u8, count: usize);
391 /// Equivalent to the appropriate `llvm.memcpy.p0i8.0i8.*` intrinsic, with
392 /// a size of `count` * `size_of::<T>()` and an alignment of
393 /// `min_align_of::<T>()`
395 /// The volatile parameter is set to `true`, so it will not be optimized out.
396 pub fn volatile_copy_nonoverlapping_memory<T>(dst: *mut T, src: *const T,
398 /// Equivalent to the appropriate `llvm.memmove.p0i8.0i8.*` intrinsic, with
399 /// a size of `count` * `size_of::<T>()` and an alignment of
400 /// `min_align_of::<T>()`
402 /// The volatile parameter is set to `true`, so it will not be optimized out.
403 pub fn volatile_copy_memory<T>(dst: *mut T, src: *const T, count: usize);
404 /// Equivalent to the appropriate `llvm.memset.p0i8.*` intrinsic, with a
405 /// size of `count` * `size_of::<T>()` and an alignment of
406 /// `min_align_of::<T>()`.
408 /// The volatile parameter is set to `true`, so it will not be optimized out.
409 pub fn volatile_set_memory<T>(dst: *mut T, val: u8, count: usize);
411 /// Perform a volatile load from the `src` pointer.
412 pub fn volatile_load<T>(src: *const T) -> T;
413 /// Perform a volatile store to the `dst` pointer.
414 pub fn volatile_store<T>(dst: *mut T, val: T);
416 /// Returns the square root of an `f32`
417 pub fn sqrtf32(x: f32) -> f32;
418 /// Returns the square root of an `f64`
419 pub fn sqrtf64(x: f64) -> f64;
421 /// Raises an `f32` to an integer power.
422 pub fn powif32(a: f32, x: i32) -> f32;
423 /// Raises an `f64` to an integer power.
424 pub fn powif64(a: f64, x: i32) -> f64;
426 /// Returns the sine of an `f32`.
427 pub fn sinf32(x: f32) -> f32;
428 /// Returns the sine of an `f64`.
429 pub fn sinf64(x: f64) -> f64;
431 /// Returns the cosine of an `f32`.
432 pub fn cosf32(x: f32) -> f32;
433 /// Returns the cosine of an `f64`.
434 pub fn cosf64(x: f64) -> f64;
436 /// Raises an `f32` to an `f32` power.
437 pub fn powf32(a: f32, x: f32) -> f32;
438 /// Raises an `f64` to an `f64` power.
439 pub fn powf64(a: f64, x: f64) -> f64;
441 /// Returns the exponential of an `f32`.
442 pub fn expf32(x: f32) -> f32;
443 /// Returns the exponential of an `f64`.
444 pub fn expf64(x: f64) -> f64;
446 /// Returns 2 raised to the power of an `f32`.
447 pub fn exp2f32(x: f32) -> f32;
448 /// Returns 2 raised to the power of an `f64`.
449 pub fn exp2f64(x: f64) -> f64;
451 /// Returns the natural logarithm of an `f32`.
452 pub fn logf32(x: f32) -> f32;
453 /// Returns the natural logarithm of an `f64`.
454 pub fn logf64(x: f64) -> f64;
456 /// Returns the base 10 logarithm of an `f32`.
457 pub fn log10f32(x: f32) -> f32;
458 /// Returns the base 10 logarithm of an `f64`.
459 pub fn log10f64(x: f64) -> f64;
461 /// Returns the base 2 logarithm of an `f32`.
462 pub fn log2f32(x: f32) -> f32;
463 /// Returns the base 2 logarithm of an `f64`.
464 pub fn log2f64(x: f64) -> f64;
466 /// Returns `a * b + c` for `f32` values.
467 pub fn fmaf32(a: f32, b: f32, c: f32) -> f32;
468 /// Returns `a * b + c` for `f64` values.
469 pub fn fmaf64(a: f64, b: f64, c: f64) -> f64;
471 /// Returns the absolute value of an `f32`.
472 pub fn fabsf32(x: f32) -> f32;
473 /// Returns the absolute value of an `f64`.
474 pub fn fabsf64(x: f64) -> f64;
476 /// Copies the sign from `y` to `x` for `f32` values.
477 pub fn copysignf32(x: f32, y: f32) -> f32;
478 /// Copies the sign from `y` to `x` for `f64` values.
479 pub fn copysignf64(x: f64, y: f64) -> f64;
481 /// Returns the largest integer less than or equal to an `f32`.
482 pub fn floorf32(x: f32) -> f32;
483 /// Returns the largest integer less than or equal to an `f64`.
484 pub fn floorf64(x: f64) -> f64;
486 /// Returns the smallest integer greater than or equal to an `f32`.
487 pub fn ceilf32(x: f32) -> f32;
488 /// Returns the smallest integer greater than or equal to an `f64`.
489 pub fn ceilf64(x: f64) -> f64;
491 /// Returns the integer part of an `f32`.
492 pub fn truncf32(x: f32) -> f32;
493 /// Returns the integer part of an `f64`.
494 pub fn truncf64(x: f64) -> f64;
496 /// Returns the nearest integer to an `f32`. May raise an inexact floating-point exception
497 /// if the argument is not an integer.
498 pub fn rintf32(x: f32) -> f32;
499 /// Returns the nearest integer to an `f64`. May raise an inexact floating-point exception
500 /// if the argument is not an integer.
501 pub fn rintf64(x: f64) -> f64;
503 /// Returns the nearest integer to an `f32`.
504 pub fn nearbyintf32(x: f32) -> f32;
505 /// Returns the nearest integer to an `f64`.
506 pub fn nearbyintf64(x: f64) -> f64;
508 /// Returns the nearest integer to an `f32`. Rounds half-way cases away from zero.
509 pub fn roundf32(x: f32) -> f32;
510 /// Returns the nearest integer to an `f64`. Rounds half-way cases away from zero.
511 pub fn roundf64(x: f64) -> f64;
513 /// Returns the number of bits set in a `u8`.
514 pub fn ctpop8(x: u8) -> u8;
515 /// Returns the number of bits set in a `u16`.
516 pub fn ctpop16(x: u16) -> u16;
517 /// Returns the number of bits set in a `u32`.
518 pub fn ctpop32(x: u32) -> u32;
519 /// Returns the number of bits set in a `u64`.
520 pub fn ctpop64(x: u64) -> u64;
522 /// Returns the number of leading bits unset in a `u8`.
523 pub fn ctlz8(x: u8) -> u8;
524 /// Returns the number of leading bits unset in a `u16`.
525 pub fn ctlz16(x: u16) -> u16;
526 /// Returns the number of leading bits unset in a `u32`.
527 pub fn ctlz32(x: u32) -> u32;
528 /// Returns the number of leading bits unset in a `u64`.
529 pub fn ctlz64(x: u64) -> u64;
531 /// Returns the number of trailing bits unset in a `u8`.
532 pub fn cttz8(x: u8) -> u8;
533 /// Returns the number of trailing bits unset in a `u16`.
534 pub fn cttz16(x: u16) -> u16;
535 /// Returns the number of trailing bits unset in a `u32`.
536 pub fn cttz32(x: u32) -> u32;
537 /// Returns the number of trailing bits unset in a `u64`.
538 pub fn cttz64(x: u64) -> u64;
540 /// Reverses the bytes in a `u16`.
541 pub fn bswap16(x: u16) -> u16;
542 /// Reverses the bytes in a `u32`.
543 pub fn bswap32(x: u32) -> u32;
544 /// Reverses the bytes in a `u64`.
545 pub fn bswap64(x: u64) -> u64;
547 /// Performs checked `i8` addition.
548 pub fn i8_add_with_overflow(x: i8, y: i8) -> (i8, bool);
549 /// Performs checked `i16` addition.
550 pub fn i16_add_with_overflow(x: i16, y: i16) -> (i16, bool);
551 /// Performs checked `i32` addition.
552 pub fn i32_add_with_overflow(x: i32, y: i32) -> (i32, bool);
553 /// Performs checked `i64` addition.
554 pub fn i64_add_with_overflow(x: i64, y: i64) -> (i64, bool);
556 /// Performs checked `u8` addition.
557 pub fn u8_add_with_overflow(x: u8, y: u8) -> (u8, bool);
558 /// Performs checked `u16` addition.
559 pub fn u16_add_with_overflow(x: u16, y: u16) -> (u16, bool);
560 /// Performs checked `u32` addition.
561 pub fn u32_add_with_overflow(x: u32, y: u32) -> (u32, bool);
562 /// Performs checked `u64` addition.
563 pub fn u64_add_with_overflow(x: u64, y: u64) -> (u64, bool);
565 /// Performs checked `i8` subtraction.
566 pub fn i8_sub_with_overflow(x: i8, y: i8) -> (i8, bool);
567 /// Performs checked `i16` subtraction.
568 pub fn i16_sub_with_overflow(x: i16, y: i16) -> (i16, bool);
569 /// Performs checked `i32` subtraction.
570 pub fn i32_sub_with_overflow(x: i32, y: i32) -> (i32, bool);
571 /// Performs checked `i64` subtraction.
572 pub fn i64_sub_with_overflow(x: i64, y: i64) -> (i64, bool);
574 /// Performs checked `u8` subtraction.
575 pub fn u8_sub_with_overflow(x: u8, y: u8) -> (u8, bool);
576 /// Performs checked `u16` subtraction.
577 pub fn u16_sub_with_overflow(x: u16, y: u16) -> (u16, bool);
578 /// Performs checked `u32` subtraction.
579 pub fn u32_sub_with_overflow(x: u32, y: u32) -> (u32, bool);
580 /// Performs checked `u64` subtraction.
581 pub fn u64_sub_with_overflow(x: u64, y: u64) -> (u64, bool);
583 /// Performs checked `i8` multiplication.
584 pub fn i8_mul_with_overflow(x: i8, y: i8) -> (i8, bool);
585 /// Performs checked `i16` multiplication.
586 pub fn i16_mul_with_overflow(x: i16, y: i16) -> (i16, bool);
587 /// Performs checked `i32` multiplication.
588 pub fn i32_mul_with_overflow(x: i32, y: i32) -> (i32, bool);
589 /// Performs checked `i64` multiplication.
590 pub fn i64_mul_with_overflow(x: i64, y: i64) -> (i64, bool);
592 /// Performs checked `u8` multiplication.
593 pub fn u8_mul_with_overflow(x: u8, y: u8) -> (u8, bool);
594 /// Performs checked `u16` multiplication.
595 pub fn u16_mul_with_overflow(x: u16, y: u16) -> (u16, bool);
596 /// Performs checked `u32` multiplication.
597 pub fn u32_mul_with_overflow(x: u32, y: u32) -> (u32, bool);
598 /// Performs checked `u64` multiplication.
599 pub fn u64_mul_with_overflow(x: u64, y: u64) -> (u64, bool);
601 /// Returns (a + b) mod 2^N, where N is the width of N in bits.
602 pub fn overflowing_add<T>(a: T, b: T) -> T;
603 /// Returns (a - b) mod 2^N, where N is the width of N in bits.
604 pub fn overflowing_sub<T>(a: T, b: T) -> T;
605 /// Returns (a * b) mod 2^N, where N is the width of N in bits.
606 pub fn overflowing_mul<T>(a: T, b: T) -> T;
608 /// Performs an unchecked signed division, which results in undefined behavior,
609 /// in cases where y == 0, or x == isize::MIN and y == -1
610 pub fn unchecked_sdiv<T>(x: T, y: T) -> T;
611 /// Performs an unchecked unsigned division, which results in undefined behavior,
612 /// in cases where y == 0
613 pub fn unchecked_udiv<T>(x: T, y: T) -> T;
615 /// Returns the remainder of an unchecked signed division, which results in
616 /// undefined behavior, in cases where y == 0, or x == isize::MIN and y == -1
617 pub fn unchecked_srem<T>(x: T, y: T) -> T;
618 /// Returns the remainder of an unchecked unsigned division, which results in
619 /// undefined behavior, in cases where y == 0
620 pub fn unchecked_urem<T>(x: T, y: T) -> T;
622 /// Returns the value of the discriminant for the variant in 'v',
623 /// cast to a `u64`; if `T` has no discriminant, returns 0.
624 pub fn discriminant_value<T>(v: &T) -> u64;
626 /// Rust's "try catch" construct which invokes the function pointer `f` with
627 /// the data pointer `data`, returning the exception payload if an exception
628 /// is thrown (aka the thread panics).
629 pub fn try(f: fn(*mut u8), data: *mut u8) -> *mut u8;