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// Copyright 2016 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.
//! Defintion of functions like _start for the linker
use sys::syscall::exit;
#[unstable(feature = "sys_rt", issue = "0")]
#[no_mangle]
#[naked]
#[cfg(target_arch = "x86")]
pub unsafe fn _start() {
asm!("push esp
call _start_stack
pop esp"
:
:
: "memory"
: "intel", "volatile");
let _ = exit(0);
}
#[unstable(feature = "sys_rt", issue = "0")]
#[no_mangle]
#[naked]
#[cfg(target_arch = "x86_64")]
pub unsafe fn _start() {
asm!("mov rdi, rsp
and rsp, 0xFFFFFFFFFFFFFFF0
call _start_stack"
:
:
: "memory"
: "intel", "volatile");
let _ = exit(0);
}
#[unstable(feature = "sys_rt", issue = "0")]
#[no_mangle]
pub unsafe extern "C" fn _start_stack(stack: *const usize){
extern "C" {
fn main(argc: usize, argv: *const *const u8) -> usize;
}
let argc = *stack as usize;
let argv = stack.offset(1) as *const *const u8;
let _ = exit(main(argc, argv));
}
/// Memcpy
///
/// Copy N bytes of memory from one location to another.
#[unstable(feature = "sys_rt", issue = "0")]
#[no_mangle]
pub unsafe extern fn memcpy(dest: *mut u8, src: *const u8,
n: usize) -> *mut u8 {
let mut i = 0;
while i < n {
*((dest as usize + i) as *mut u8) = *((src as usize + i) as *const u8);
i += 1;
}
dest
}
/// Memmove
///
/// Copy N bytes of memory from src to dest. The memory areas may overlap.
#[unstable(feature = "sys_rt", issue = "0")]
#[no_mangle]
pub unsafe extern fn memmove(dest: *mut u8, src: *const u8,
n: usize) -> *mut u8 {
if src < dest as *const u8 {
let mut i = n;
while i != 0 {
i -= 1;
*((dest as usize + i) as *mut u8) = *((src as usize + i) as *const u8);
}
} else {
let mut i = 0;
while i < n {
*((dest as usize + i) as *mut u8) = *((src as usize + i) as *const u8);
i += 1;
}
}
dest
}
/// Memset
///
/// Fill a block of memory with a specified value.
#[unstable(feature = "sys_rt", issue = "0")]
#[no_mangle]
pub unsafe extern fn memset(dest: *mut u8, c: i32, n: usize) -> *mut u8 {
let mut i = 0;
while i < n {
*((dest as usize + i) as *mut u8) = c as u8;
i += 1;
}
dest
}
/// Memcmp
///
/// Compare two blocks of memory.
#[unstable(feature = "sys_rt", issue = "0")]
#[no_mangle]
pub unsafe extern fn memcmp(s1: *const u8, s2: *const u8, n: usize) -> i32 {
let mut i = 0;
while i < n {
let a = *((s1 as usize + i) as *const u8);
let b = *((s2 as usize + i) as *const u8);
if a != b {
return a as i32 - b as i32
}
i += 1;
}
0
}
|
