I added smes and rmes system calls to a7out and wrote some code

in src/other/fork_test.s to test it. It's not working quite right
yet, we keep getting wait() returning -1 in a7out even though there
is a child process.

src/other/fork_test.s

@@ -7,14 +7,33 @@ main:
 child:
    lac d1
    sys write; childmsg;  3
+   sys smes
    sys exit
 
 parent:
+   dac pid	" save the childs pid
    lac d1
    sys write; parentmsg; 4
+
+   sys rmes	" wait for the child to exit
+   sad pid	" did we get the same pid back?
+     jmp ok
+
+wrong:
+   lac d1
+   sys write; badpid;  4
+   sys exit
+
+ok:
+   lac d1
+   sys write; goodpid;  4
    sys exit
 
 d1: 1		" stdout fd
+pid: 0		" child's pid
 
 parentmsg: <pa>; <re>; <nt>; 012000
 childmsg:  <ch>; <il>; <d 012
+
+goodpid: <go>; <od>; <pi>; <d 012
+badpid: <ba>; <dp>; <id>; 012000