feature: add threads (WIP)

libsys/src/abi.rs

@@ -4,6 +4,8 @@ pub const SYS_EX_NANOSLEEP: usize = 129;
 pub const SYS_EX_SIGNAL: usize = 130;
 pub const SYS_EX_SIGRETURN: usize = 131;
 pub const SYS_EX_KILL: usize = 132;
+pub const SYS_EX_CLONE: usize = 133;
+pub const SYS_EX_YIELD: usize = 134;
 
 pub const SYS_EXIT: usize = 1;
 pub const SYS_READ: usize = 2;

libsys/src/calls.rs

@@ -271,6 +271,32 @@ pub fn sys_ex_kill(pid: SignalDestination, signum: Signal) -> Result<(), Errno>
     })
 }
 
+#[inline(always)]
+pub fn sys_ex_clone(entry: usize, stack: usize, arg: usize) -> Result<usize, Errno> {
+    Errno::from_syscall(unsafe {
+        syscall!(
+            abi::SYS_EX_CLONE,
+            argn!(entry),
+            argn!(stack),
+            argn!(arg)
+        )
+    })
+}
+
+#[inline(always)]
+pub fn sys_ex_yield() {
+    unsafe {
+        syscall!(abi::SYS_EX_YIELD);
+    }
+}
+
+#[inline(always)]
+pub fn sys_ex_undefined() {
+    unsafe {
+        syscall!(0);
+    }
+}
+
 #[inline(always)]
 pub fn sys_select(
     read_fds: Option<&mut FdSet>,

libsys/src/error.rs

@@ -47,6 +47,6 @@ impl Errno {
 
 impl From<usize> for Errno {
     fn from(u: usize) -> Errno {
-        todo!()
+        unsafe { core::mem::transmute(u as u32) }
     }
 }