add weak `memcpy` et al symbols

closes #28
This commit is contained in:
Jorge Aparicio 2016-08-12 21:20:56 -05:00
parent adfb1ff851
commit 265939fc00
2 changed files with 63 additions and 0 deletions

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@ -1,10 +1,12 @@
#![allow(unused_features)]
#![feature(asm)]
#![feature(core_intrinsics)]
#![feature(linkage)]
#![feature(naked_functions)]
#![cfg_attr(not(test), no_std)]
// TODO(rust-lang/rust#35021) uncomment when that PR lands
// #![feature(rustc_builtins)]
#![no_builtins]
// We disable #[no_mangle] for tests so that we can verify the test results
// against the native compiler-rt implementations of the builtins.
@ -20,6 +22,7 @@ extern crate core;
pub mod arm;
pub mod udiv;
pub mod mem;
pub mod mul;
pub mod shift;

60
src/mem.rs Normal file
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@ -0,0 +1,60 @@
// NOTE Copied verbatim from the rlibc crate
// cf. https://crates.io/crates/rlibc
#[linkage = "weak"]
#[no_mangle]
pub unsafe extern "C" fn memcpy(dest: *mut u8, src: *const u8, n: usize) -> *mut u8 {
let mut i = 0;
while i < n {
*dest.offset(i as isize) = *src.offset(i as isize);
i += 1;
}
dest
}
#[linkage = "weak"]
#[no_mangle]
pub unsafe extern "C" fn memmove(dest: *mut u8, src: *const u8, n: usize) -> *mut u8 {
if src < dest as *const u8 {
// copy from end
let mut i = n;
while i != 0 {
i -= 1;
*dest.offset(i as isize) = *src.offset(i as isize);
}
} else {
// copy from beginning
let mut i = 0;
while i < n {
*dest.offset(i as isize) = *src.offset(i as isize);
i += 1;
}
}
dest
}
#[linkage = "weak"]
#[no_mangle]
pub unsafe extern "C" fn memset(s: *mut u8, c: i32, n: usize) -> *mut u8 {
let mut i = 0;
while i < n {
*s.offset(i as isize) = c as u8;
i += 1;
}
s
}
#[linkage = "weak"]
#[no_mangle]
pub unsafe extern "C" fn memcmp(s1: *const u8, s2: *const u8, n: usize) -> i32 {
let mut i = 0;
while i < n {
let a = *s1.offset(i as isize);
let b = *s2.offset(i as isize);
if a != b {
return a as i32 - b as i32;
}
i += 1;
}
0
}