portable_simd
)Expand description
Portable SIMD module.
This module offers a portable abstraction for SIMD operations that is not bound to any particular hardware architecture.
§What is “portable”?
This module provides a SIMD implementation that is fast and predictable on any target.
§Portable SIMD works on every target
Unlike target-specific SIMD in std::arch
, portable SIMD compiles for every target.
In this regard, it is just like “regular” Rust.
§Portable SIMD is consistent between targets
A program using portable SIMD can expect identical behavior on any target.
In most regards, Simd<T, N>
can be thought of as a parallelized [T; N]
and operates like a sequence of T
.
This has one notable exception: a handful of older architectures (e.g. armv7
and powerpc
) flush subnormal f32
values to zero.
On these architectures, subnormal f32
input values are replaced with zeros, and any operation producing subnormal f32
values produces zeros instead.
This doesn’t affect most architectures or programs.
§Operations use the best instructions available
Operations provided by this module compile to the best available SIMD instructions.
Portable SIMD is not a low-level vendor library, and operations in portable SIMD do not necessarily map to a single instruction. Instead, they map to a reasonable implementation of the operation for the target.
Consistency between targets is not compromised to use faster or fewer instructions.
In some cases, std::arch
will provide a faster function that has slightly different behavior than the std::simd
equivalent.
For example, _mm_min_ps
1 can be slightly faster than SimdFloat::simd_min
, but does not conform to the IEEE standard also used by f32::min
.
When necessary, Simd<T, N>
can be converted to the types provided by std::arch
to make use of target-specific functions.
Many targets simply don’t have SIMD, or don’t support SIMD for a particular element type. In those cases, regular scalar operations are generated instead.
_mm_min_ps(x, y)
is equivalent tox.simd_lt(y).select(x, y)
↩
Modules§
- cmp
Experimental Traits for comparing and ordering vectors. - num
Experimental Traits for vectors with numeric elements. - prelude
Experimental The portable SIMD prelude. - ptr
Experimental Traits for vectors of pointers.
Macros§
- simd_
swizzle Experimental Constructs a new SIMD vector by copying elements from selected elements in other vectors.
Structs§
- Lane
Count Experimental Specifies the number of lanes in a SIMD vector as a type. - Mask
Experimental A SIMD vector mask forN
elements of width specified byElement
. - Simd
Experimental A SIMD vector with the shape of[T; N]
but the operations ofT
.
Traits§
- Mask
Element Experimental Marker trait for types that may be used as SIMD mask elements. - Simd
Cast Experimental Supporting trait forSimd::cast
. Typically doesn’t need to be used directly. - Simd
Element Experimental Marker trait for types that may be used as SIMD vector elements. - Supported
Lane Count Experimental Statically guarantees that a lane count is marked as supported. - Swizzle
Experimental Creates a vector from the elements of another vector. - ToBytes
Experimental Converts SIMD vectors to vectors of bytes
Type Aliases§
- f32x1
Experimental A SIMD vector with one element of typef32
. - f32x2
Experimental A SIMD vector with two elements of typef32
. - f32x4
Experimental A SIMD vector with four elements of typef32
. - f32x8
Experimental A SIMD vector with eight elements of typef32
. - f32x16
Experimental A SIMD vector with 16 elements of typef32
. - f32x32
Experimental A SIMD vector with 32 elements of typef32
. - f32x64
Experimental A SIMD vector with 64 elements of typef32
. - f64x1
Experimental A SIMD vector with one element of typef64
. - f64x2
Experimental A SIMD vector with two elements of typef64
. - f64x4
Experimental A SIMD vector with four elements of typef64
. - f64x8
Experimental A SIMD vector with eight elements of typef64
. - f64x16
Experimental A SIMD vector with 16 elements of typef64
. - f64x32
Experimental A SIMD vector with 32 elements of typef64
. - f64x64
Experimental A SIMD vector with 64 elements of typef64
. - i8x1
Experimental A SIMD vector with one element of typei8
. - i8x2
Experimental A SIMD vector with two elements of typei8
. - i8x4
Experimental A SIMD vector with four elements of typei8
. - i8x8
Experimental A SIMD vector with eight elements of typei8
. - i8x16
Experimental A SIMD vector with 16 elements of typei8
. - i8x32
Experimental A SIMD vector with 32 elements of typei8
. - i8x64
Experimental A SIMD vector with 64 elements of typei8
. - i16x1
Experimental A SIMD vector with one element of typei16
. - i16x2
Experimental A SIMD vector with two elements of typei16
. - i16x4
Experimental A SIMD vector with four elements of typei16
. - i16x8
Experimental A SIMD vector with eight elements of typei16
. - i16x16
Experimental A SIMD vector with 16 elements of typei16
. - i16x32
Experimental A SIMD vector with 32 elements of typei16
. - i16x64
Experimental A SIMD vector with 64 elements of typei16
. - i32x1
Experimental A SIMD vector with one element of typei32
. - i32x2
Experimental A SIMD vector with two elements of typei32
. - i32x4
Experimental A SIMD vector with four elements of typei32
. - i32x8
Experimental A SIMD vector with eight elements of typei32
. - i32x16
Experimental A SIMD vector with 16 elements of typei32
. - i32x32
Experimental A SIMD vector with 32 elements of typei32
. - i32x64
Experimental A SIMD vector with 64 elements of typei32
. - i64x1
Experimental A SIMD vector with one element of typei64
. - i64x2
Experimental A SIMD vector with two elements of typei64
. - i64x4
Experimental A SIMD vector with four elements of typei64
. - i64x8
Experimental A SIMD vector with eight elements of typei64
. - i64x16
Experimental A SIMD vector with 16 elements of typei64
. - i64x32
Experimental A SIMD vector with 32 elements of typei64
. - i64x64
Experimental A SIMD vector with 64 elements of typei64
. - isizex1
Experimental A SIMD vector with one element of typeisize
. - isizex2
Experimental A SIMD vector with two elements of typeisize
. - isizex4
Experimental A SIMD vector with four elements of typeisize
. - isizex8
Experimental A SIMD vector with eight elements of typeisize
. - isizex16
Experimental A SIMD vector with 16 elements of typeisize
. - isizex32
Experimental A SIMD vector with 32 elements of typeisize
. - isizex64
Experimental A SIMD vector with 64 elements of typeisize
. - mask8x1
Experimental A SIMD mask with one element for vectors with 8-bit element types. - mask8x2
Experimental A SIMD mask with two elements for vectors with 8-bit element types. - mask8x4
Experimental A SIMD mask with four elements for vectors with 8-bit element types. - mask8x8
Experimental A SIMD mask with eight elements for vectors with 8-bit element types. - mask8x16
Experimental A SIMD mask with 16 elements for vectors with 8-bit element types. - mask8x32
Experimental A SIMD mask with 32 elements for vectors with 8-bit element types. - mask8x64
Experimental A SIMD mask with 64 elements for vectors with 8-bit element types. - mask16x1
Experimental A SIMD mask with one element for vectors with 16-bit element types. - mask16x2
Experimental A SIMD mask with two elements for vectors with 16-bit element types. - mask16x4
Experimental A SIMD mask with four elements for vectors with 16-bit element types. - mask16x8
Experimental A SIMD mask with eight elements for vectors with 16-bit element types. - mask16x16
Experimental A SIMD mask with 16 elements for vectors with 16-bit element types. - mask16x32
Experimental A SIMD mask with 32 elements for vectors with 16-bit element types. - mask16x64
Experimental A SIMD mask with 64 elements for vectors with 16-bit element types. - mask32x1
Experimental A SIMD mask with one element for vectors with 32-bit element types. - mask32x2
Experimental A SIMD mask with two elements for vectors with 32-bit element types. - mask32x4
Experimental A SIMD mask with four elements for vectors with 32-bit element types. - mask32x8
Experimental A SIMD mask with eight elements for vectors with 32-bit element types. - mask32x16
Experimental A SIMD mask with 16 elements for vectors with 32-bit element types. - mask32x32
Experimental A SIMD mask with 32 elements for vectors with 32-bit element types. - mask32x64
Experimental A SIMD mask with 64 elements for vectors with 32-bit element types. - mask64x1
Experimental A SIMD mask with one element for vectors with 64-bit element types. - mask64x2
Experimental A SIMD mask with two elements for vectors with 64-bit element types. - mask64x4
Experimental A SIMD mask with four elements for vectors with 64-bit element types. - mask64x8
Experimental A SIMD mask with eight elements for vectors with 64-bit element types. - mask64x16
Experimental A SIMD mask with 16 elements for vectors with 64-bit element types. - mask64x32
Experimental A SIMD mask with 32 elements for vectors with 64-bit element types. - mask64x64
Experimental A SIMD mask with 64 elements for vectors with 64-bit element types. - masksizex1
Experimental A SIMD mask with one element for vectors with pointer-sized element types. - masksizex2
Experimental A SIMD mask with two elements for vectors with pointer-sized element types. - masksizex4
Experimental A SIMD mask with four elements for vectors with pointer-sized element types. - masksizex8
Experimental A SIMD mask with eight elements for vectors with pointer-sized element types. - masksizex16
Experimental A SIMD mask with 16 elements for vectors with pointer-sized element types. - masksizex32
Experimental A SIMD mask with 32 elements for vectors with pointer-sized element types. - masksizex64
Experimental A SIMD mask with 64 elements for vectors with pointer-sized element types. - u8x1
Experimental A SIMD vector with one element of typeu8
. - u8x2
Experimental A SIMD vector with two elements of typeu8
. - u8x4
Experimental A SIMD vector with four elements of typeu8
. - u8x8
Experimental A SIMD vector with eight elements of typeu8
. - u8x16
Experimental A SIMD vector with 16 elements of typeu8
. - u8x32
Experimental A SIMD vector with 32 elements of typeu8
. - u8x64
Experimental A SIMD vector with 64 elements of typeu8
. - u16x1
Experimental A SIMD vector with one element of typeu16
. - u16x2
Experimental A SIMD vector with two elements of typeu16
. - u16x4
Experimental A SIMD vector with four elements of typeu16
. - u16x8
Experimental A SIMD vector with eight elements of typeu16
. - u16x16
Experimental A SIMD vector with 16 elements of typeu16
. - u16x32
Experimental A SIMD vector with 32 elements of typeu16
. - u16x64
Experimental A SIMD vector with 64 elements of typeu16
. - u32x1
Experimental A SIMD vector with one element of typeu32
. - u32x2
Experimental A SIMD vector with two elements of typeu32
. - u32x4
Experimental A SIMD vector with four elements of typeu32
. - u32x8
Experimental A SIMD vector with eight elements of typeu32
. - u32x16
Experimental A SIMD vector with 16 elements of typeu32
. - u32x32
Experimental A SIMD vector with 32 elements of typeu32
. - u32x64
Experimental A SIMD vector with 64 elements of typeu32
. - u64x1
Experimental A SIMD vector with one element of typeu64
. - u64x2
Experimental A SIMD vector with two elements of typeu64
. - u64x4
Experimental A SIMD vector with four elements of typeu64
. - u64x8
Experimental A SIMD vector with eight elements of typeu64
. - u64x16
Experimental A SIMD vector with 16 elements of typeu64
. - u64x32
Experimental A SIMD vector with 32 elements of typeu64
. - u64x64
Experimental A SIMD vector with 64 elements of typeu64
. - usizex1
Experimental A SIMD vector with one element of typeusize
. - usizex2
Experimental A SIMD vector with two elements of typeusize
. - usizex4
Experimental A SIMD vector with four elements of typeusize
. - usizex8
Experimental A SIMD vector with eight elements of typeusize
. - usizex16
Experimental A SIMD vector with 16 elements of typeusize
. - usizex32
Experimental A SIMD vector with 32 elements of typeusize
. - usizex64
Experimental A SIMD vector with 64 elements of typeusize
.