else3.cod

为PL0编译器

=== COMPILE PL0 ===
  0 PROGRAM EX01; 
  0 VAR A,B,C; 
  1 BEGIN 
  2    READ(A); 
  4    READ(B); 
  6   IF A<=0 
  8   THEN  
  9    IF B>=0 
 12      THEN 
 13        C:=1 
 15    ELSE C:=0 
 18   ELSE 
 20    IF B>=0 
 22      THEN 
 23        C:=0 
 25    ELSE C:=1; 
 29   WRITE(A); 
 32   WRITE(B); 
 35   WRITE(C) 
 37 END. 
  0  JMP   0   1
  1  INI   0   6
  2  OPR   0  16
  3  STO   0   3
  4  OPR   0  16
  5  STO   0   4
  6  LOD   0   3
  7  LIT   0   0
  8  OPR   0  13
  9  JPC   0  20
 10  LOD   0   4
 11  LIT   0   0
 12  OPR   0  11
 13  JPC   0  17
 14  LIT   0   1
 15  STO   0   5
 16  JMP   0  19
 17  LIT   0   0
 18  STO   0   5
 19  JMP   0  29
 20  LOD   0   4
 21  LIT   0   0
 22  OPR   0  11
 23  JPC   0  27
 24  LIT   0   0
 25  STO   0   5
 26  JMP   0  29
 27  LIT   0   1
 28  STO   0   5
 29  LOD   0   3
 30  OPR   0  14
 31  OPR   0  15
 32  LOD   0   4
 33  OPR   0  14
 34  OPR   0  15
 35  LOD   0   5
 36  OPR   0  14
 37  OPR   0  15
 38  OPR   0   0
~~~ RUN PL0 ~~~
? -1
? -3
-1
-3
0
~~~ END PL0 ~~~