Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Tidy up unordered elementwise atomic memory intrinsics #312

Merged
merged 1 commit into from
Aug 23, 2019
Merged

Tidy up unordered elementwise atomic memory intrinsics #312

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
16 changes: 12 additions & 4 deletions src/mem.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,7 @@ type c_int = i16;
#[cfg(not(target_pointer_width = "16"))]
type c_int = i32;

use core::intrinsics::{atomic_load_unordered, atomic_store_unordered, unchecked_div};
use core::intrinsics::{atomic_load_unordered, atomic_store_unordered, exact_div};
use core::mem;
use core::ops::{BitOr, Shl};

Expand Down Expand Up @@ -63,9 +63,10 @@ pub unsafe extern "C" fn memcmp(s1: *const u8, s2: *const u8, n: usize) -> i32 {
0
}

// `bytes` must be a multiple of `mem::size_of::<T>()`
fn memcpy_element_unordered_atomic<T: Copy>(dest: *mut T, src: *const T, bytes: usize) {
unsafe {
let n = unchecked_div(bytes, mem::size_of::<T>());
let n = exact_div(bytes, mem::size_of::<T>());
let mut i = 0;
while i < n {
atomic_store_unordered(dest.add(i), atomic_load_unordered(src.add(i)));
Expand All @@ -74,9 +75,10 @@ fn memcpy_element_unordered_atomic<T: Copy>(dest: *mut T, src: *const T, bytes:
}
}

// `bytes` must be a multiple of `mem::size_of::<T>()`
fn memmove_element_unordered_atomic<T: Copy>(dest: *mut T, src: *const T, bytes: usize) {
unsafe {
let n = unchecked_div(bytes, mem::size_of::<T>());
let n = exact_div(bytes, mem::size_of::<T>());
if src < dest as *const T {
// copy from end
let mut i = n;
Expand All @@ -95,18 +97,24 @@ fn memmove_element_unordered_atomic<T: Copy>(dest: *mut T, src: *const T, bytes:
}
}

// `T` must be a primitive integer type, and `bytes` must be a multiple of `mem::size_of::<T>()`
fn memset_element_unordered_atomic<T>(s: *mut T, c: u8, bytes: usize)
where
T: Copy + From<u8> + Shl<u32, Output = T> + BitOr<T, Output = T>,
{
unsafe {
let n = unchecked_div(bytes, mem::size_of::<T>());
let n = exact_div(bytes, mem::size_of::<T>());

// Construct a value of type `T` consisting of repeated `c`
// bytes, to let us ensure we write each `T` atomically.
let mut x = T::from(c);
let mut i = 1;
while i < mem::size_of::<T>() {
x = x << 8 | T::from(c);
i += 1;
}

// Write it to `s`
let mut i = 0;
while i < n {
atomic_store_unordered(s.add(i), x);
Expand Down