Function syscall

user/src/syscall.rs:33–45

(id: usize, args: [usize; 3])

const SYSCALL_KEY_PRESSED: usize = 3001;

fn syscall(id: usize, args: [usize; 3]) -> isize {
    let mut ret: isize;
    unsafe {
        core::arch::asm!(
            "ecall",
            inlateout("x10") args[0] => ret,
            in("x11") args[1],
            in("x12") args[2],
            in("x17") id
        );
    }
    ret
}

pub fn sys_dup(fd: usize) -> isize {
    syscall(SYSCALL_DUP, [fd, 0, 0])