Added more syscalls

examples/shell/shell.q

@@ -0,0 +1,31 @@
+import mem
+import sys
+
+main() {
+	length := 256
+	command := mem.alloc(length)
+	argv := mem.alloc(1)
+	envp := mem.alloc(1)
+	info := mem.alloc(24)
+
+	loop {
+		sys.write(1, "$ ", 2)
+		n := sys.read(0, command, length)
+
+		if n <= 0 {
+			return
+		}
+
+		// TODO: Indexing by register
+		command[7] = '\0'
+
+		pid := sys.fork()
+
+		if pid == 0 {
+			sys.execve(command, argv, envp)
+			return
+		}
+
+		sys.waitid(0, pid, info, 4)
+	}
+}