Add signal support - exit on signal

libstd/libc/src/funcs.rs

@@ -0,0 +1,40 @@
+use super::{c_char, size_t};
+
+pub unsafe extern fn strlen(ptr: *const c_char) -> size_t {
+    let mut i: size_t = 0;
+    while *ptr.offset(i as isize) != 0 {
+        i += 1;
+    }
+    i
+}
+
+extern crate spin;
+use core::cell::Cell;
+use self::spin::Mutex;
+
+/// The randomness state.
+///
+/// This is updated when a new random integer is read.
+static STATE: Mutex<[u64; 2]> = Mutex::new([0xBADF00D1, 0xDEADBEEF]);
+
+/// Get a pseudorandom integer.
+///
+/// Note that this is full-cycle, so apply a modulo when true equidistribution is needed.
+pub unsafe extern fn random() -> u64 {
+    // Fetch the state.
+    let mut state = STATE.lock();
+
+    // Store the first and second part.
+    let mut x = state[0];
+    let y = state[1];
+
+    // Put the second part into the first slot.
+    state[0] = y;
+    // Twist the first slot.
+    x ^= x << 23;
+    // Update the second slot.
+    state[1] = x ^ y ^ (x >> 17) ^ (y >> 26);
+
+    // Generate the final integer.
+    state[1].wrapping_add(y)
+}