8 box "\s-4SPARC stack\s+4" ht .2
9 box "\s-4EM stack\s+4" ht .1
10 box "\s-4SPARC stack\s+4" ht .1
11 box "\s-4EM stack\s+4" ht .1
12 box "\s-4free\s+4" ht .2
13 box "\s-4SPARC stack\s+4" ht .1
21 box "\s-4SPARC stack\s+4" ht .2
22 box "\s-4EM stack\s+4" ht .1
23 box "\s-4SPARC stack\s+4" ht .1
24 box "\s-4EM stack\s+4" ht .1
25 box "\s-4free\s+4" ht .2
26 box "\s-4SPARC stack\s+4" ht .1
27 box "\s-4EM stack\s+4" ht .1
28 box "\s-4free\s+4" ht .2
29 box "\s-4SPARC stack\s+4" ht .1
38 box invis "before signal"
40 box invis "during (1st) signal"