sicp-ex-5.31

  
  
  
 (f 'x 'y)     => all the saves and restores are superfluous. because they doesn't change the registers. 
 ((f) 'x 'y)   => all the saves and restores are superfluous. 
 (f (g 'x) y) => register proc, argl will needed save and restore. 
 (f (g 'x) 'y) => same to the above one. 

  
  
  
 (f 'x 'y)  => all the saves are not necessary. 
 ((f) 'x 'y) => not necessary too, although (f) is a compound-procedure, it will change the env register to the status where f is defined, but it will not affect the quoted 'x and 'y. 
 (f (g 'x) y) => proc and argl are necessary, save env before eval (g 'x) is necessary too, it will change the env register and y will be affected. 
 (f (g 'x) 'y) => proc and argl is necessary, but no need to save env before eval (g 'x) cause 'y is quoted, it will not fetch any value in the env, and env register will be reset to the status where f is defined