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/* IfMachine() --- This function implements the IFD & IFND conditional
                assembly machine.
                version 1.0 made for release TER_2.0 cross assembler 27 Jun 89
*/
 
#define FALSE_BLOCK     0       /* values for state variable */
#define TRUE_BLOCK      1
#define POP_TEST        2
#define ELSE_TEST       3
#define FALSE           0
#define TRUE            1
 
void IfMachine(Token)
int Token;      /* input token from calling machine */
                /* See file as.h for definition (globals) */
{
  static int State = TRUE_BLOCK, StackPt = 0, IfStack[MAXIFD];
                /* State variable, pointer to "IF stack pointer" and "Stack" */
  int Hiatus;   /* flag to break out of FSM & resume normal processing */
 
  Hiatus=FALSE; /* infinite loop to operate machine
                                 until time to break out */
  do    /* test at end */
   {
 
#ifdef DEBUG3
  printf("IfMachine state=%u , token=%u\n",State,Token);
#endif
 
   if (State == TRUE_BLOCK)     /* a block of statements processed normally */
     switch(Token) {
        case IF_TRUE:
                IfStack[StackPt]=TRUE;
                if (++StackPt > MAXIFD) {       /* check for over flow */
                        StackPt = MAXIFD;
                        error("Error:IFD/IFND nested too deep");
                        }
                /* print_line() will be done in normal processing */
                Hiatus = TRUE;  /* resume normal line processing */
                break;
        case IF_FALSE:
                IfStack[StackPt]=TRUE;
                if (++StackPt > MAXIFD) {       /* check for over flow */
                        StackPt = MAXIFD;
                        error("Error:IFD/IFND nested too deep");
                        }
                if (Pass == 2 && Lflag && !N_page)      /* need to print here */
                        print_line(); /* cuz will not return to normal */
                Token = GetToken(); /* get next line & examine for IF */
                State = FALSE_BLOCK; /* change state */
                break;
        case IF_ELSE:
                if (StackPt == 0) /* bad IF nesting */
                        error("Error: ELSE without IF");
                if (Pass == 2 && Lflag && !N_page)
                        print_line();
                Token = GetToken(); /* get next line & examine for IF */
                State = FALSE_BLOCK;
                break;
        case IF_ENDIF:
                if (StackPt == 0)       /* bad IF nesting */
                        error("Error: ENDIF without IF");
                else
                        StackPt--; /* popped state must be TRUE */
                 Hiatus = TRUE;
                 break;
        /* case NORMAL is not implemented as it represents normal line
                processing. */
        case IF_END:    /* file ended with improperly nested IFD */
                        /* this code can't actually be reached at present
                           in a TRUE_BLOCK */
                fatal("Error: file ended before IFD/IFND/ELSE/ENDIF");
                break;
        default:        /* This code can't be reached at the present.
                           Logically would happen if EOF but handled
                           else where */
                fatal("Can't get here from there.");
                break;
      }
   else if (State == FALSE_BLOCK)       /* statements not processed */
     switch(Token) {
        case IF_TRUE:   /* doesn't make any diff. Just nest IFs */
        case IF_FALSE:
                IfStack[StackPt]=FALSE;
                if (++StackPt > MAXIFD) {
                        StackPt = MAXIFD;
                        error("Error:IFD/IFND nested too deep");
                        }
                if (Pass == 2 && Lflag && !N_page)
                        print_line();
                Token = GetToken();
                break;
        case IF_ELSE:
             /* if (Pass == 2 && Lflag && !N_page) */
             /*         print_line();              */
                State = ELSE_TEST;
                break;
        case IF_ENDIF:
                State = POP_TEST;
                break;
        case IF_END:    /* file ended with improperly nested IFD */
                fatal("Fatal Error: file ended before last ENDIF");
                        /* Fatal will exit assembler.  Things are too
                           messed up.  Include file handling is else where
                           and don't want to duplicate here. */
                break;
        case IF_NORMAL: /* normal line in a FALSE BLOCK */
                if (Pass == 2 && Lflag && !N_page)
                        print_line();
                Token = GetToken();
                break;
        default:
                fatal("Fatal Error: file ended before last ENDIF");
                        /* must be EOF or something else terrible */
                break;
     }
   else if (State == POP_TEST) {        /* pop up outside nest state */
     if (StackPt == 0) {        /* bad IF nesting */
        error("Error: ENDIF without IF");
        if (Pass == 2 && Lflag && !N_page)
                        print_line();
        State = TRUE;
        }
     else {
        StackPt--;      /* pop stack */
        if (IfStack[StackPt] == TRUE) { /* back to normal */
                /* had to come from FALSE block cuz TRUE block cannot
                        be inside FALSE block */
                if (Pass == 2 && Lflag && !N_page)
                        print_line();
                State = TRUE;
                Hiatus = TRUE;  /* sleep for normal line processing */
                }
        else {  /* gotta be that stack == FALSE, still inside FALSE nest */
                if (Pass == 2 && Lflag && !N_page)
                        print_line();
                State = FALSE;
                Token = GetToken();
                }
          }
     }
   else if (State == ELSE_TEST) {       /* change state */
        if (IfStack[StackPt-1] == TRUE) {
                State = TRUE_BLOCK;
                Hiatus = TRUE;
                }
        else
                State = FALSE_BLOCK;
      }
   }
while (Hiatus == FALSE);        /* loop if not exit */
}
 
 
/* GetToken() --- get another line from within False Block and extract token
                as would be done in pseudo.c.  Returns token id:
                        IF_TRUE         IFD/IFND evaluated to TRUE
                        IF_FALSE        IFD/IFND evaluated to FALSE
                        IF_ELSE         ELSE pseudo op
                        IF_ENDIF        ENDIF pseudo op
                        IF_END          END pseudo op
                        IF_NORMAL       none of the above, perhaps assy code
                        IF_EOF          encountered end of file
                This function exists because conditional assembly was added
                as pseudo op rather than with key character ("%") and did
                not want to disturb original software topology */
 
int GetToken()  /* get another line and find token in it */
{               /* similar to make_pass() except one line at a time */
                /* most variables & constants are global */
 
struct nlist *lookup();
 
#ifndef IBM
  if (FGETS(Line,MAXBUF-1,Fd) == (char *)NULL)
#else
  if (fgets(Line,MAXBUF,Fd) == (char *)NULL)
#endif
        return(IF_EOF); /* banged into eof */
  Line_num++;
  P_force=0;
  N_page=0;
  if (!parse_line())
        return(IF_NORMAL);      /* comment line */
  if (*Op==EOS)                 /* skipping over label, probably. */
        return(IF_NORMAL);      /* strcmp() returns 0 if arg1 is NULL string */
 
  if (strcmp(Op,"ifd")==0)
        return(eval_ifd());
  else if (strcmp(Op,"ifnd")==0)
        return(eval_ifnd());
  else if (strcmp(Op,"else")==0)
        return(IF_ELSE);
  else if (strcmp(Op,"endif")==0)
        return(IF_ENDIF);
  else if (strcmp(Op,"end")==0)
        return(IF_END);
  else
        return(IF_NORMAL);      /* or might be garbage...but who cares?
                                   This is FALSE BLOCK */
}
 
 
/*
*  eval_ifd() --- evaluate an if define statement for TRUE or FALSE
*/
 
int
eval_ifd()
         {
  struct nlist *np;     /* symbol structure */
 
        if (*Operand==EOS) {
                warn("No symbol for IFD");
                return(IF_FALSE);       /* nothing to check */
                }
        if ((np=lookup(Operand)) == NULL)
                return(IF_FALSE);       /* not defined at all...yet */
        else
                if(np->def2 == Pass)
                        return(IF_TRUE); /* defined for this pass */
 
        return(IF_FALSE);       /* not defined this pass */
        }
 
/*
*  eval_ifnd() --- evaluate an if not define statement for TRUE or FALSE
*/
 
int
eval_ifnd()
 {
  struct nlist *np;     /* symbol structure */
 
        if (*Operand==EOS) {
                warn("No symbol for IFND");
                return(IF_TRUE);        /* nothing to check */
                }
        if ((np=lookup(Operand)) == NULL)
                return(IF_TRUE);        /* not defined at all...yet */
        else
                if(np->def2 == Pass)
                        return(IF_FALSE); /* defined for this pass */
 
        return(IF_TRUE);        /* not defined this pass */
 }

Line No.	Rev	Author	Line
1	74	davidgb	`/* IfMachine() --- This function implements the IFD & IFND conditional`
2			`assembly machine.`
3			`version 1.0 made for release TER_2.0 cross assembler 27 Jun 89`
4			`*/`
5
6			`#define FALSE_BLOCK 0 /* values for state variable */`
7			`#define TRUE_BLOCK 1`
8			`#define POP_TEST 2`
9			`#define ELSE_TEST 3`
10			`#define FALSE 0`
11			`#define TRUE 1`
12
13			`void IfMachine(Token)`
14			`int Token; /* input token from calling machine */`
15			`/* See file as.h for definition (globals) */`
16			`{`
17			`static int State = TRUE_BLOCK, StackPt = 0, IfStack[MAXIFD];`
18			`/* State variable, pointer to "IF stack pointer" and "Stack" */`
19			`int Hiatus; /* flag to break out of FSM & resume normal processing */`
20
21			`Hiatus=FALSE; /* infinite loop to operate machine`
22			`until time to break out */`
23			`do /* test at end */`
24			`{`
25
26			`#ifdef DEBUG3`
27			`printf("IfMachine state=%u , token=%u\n",State,Token);`
28			`#endif`
29
30			`if (State == TRUE_BLOCK) /* a block of statements processed normally */`
31			`switch(Token) {`
32			`case IF_TRUE:`
33			`IfStack[StackPt]=TRUE;`
34			`if (++StackPt > MAXIFD) { /* check for over flow */`
35			`StackPt = MAXIFD;`
36			`error("Error:IFD/IFND nested too deep");`
37			`}`
38			`/* print_line() will be done in normal processing */`
39			`Hiatus = TRUE; /* resume normal line processing */`
40			`break;`
41			`case IF_FALSE:`
42			`IfStack[StackPt]=TRUE;`
43			`if (++StackPt > MAXIFD) { /* check for over flow */`
44			`StackPt = MAXIFD;`
45			`error("Error:IFD/IFND nested too deep");`
46			`}`
47			`if (Pass == 2 && Lflag && !N_page) /* need to print here */`
48			`print_line(); /* cuz will not return to normal */`
49			`Token = GetToken(); /* get next line & examine for IF */`
50			`State = FALSE_BLOCK; /* change state */`
51			`break;`
52			`case IF_ELSE:`
53			`if (StackPt == 0) /* bad IF nesting */`
54			`error("Error: ELSE without IF");`
55			`if (Pass == 2 && Lflag && !N_page)`
56			`print_line();`
57			`Token = GetToken(); /* get next line & examine for IF */`
58			`State = FALSE_BLOCK;`
59			`break;`
60			`case IF_ENDIF:`
61			`if (StackPt == 0) /* bad IF nesting */`
62			`error("Error: ENDIF without IF");`
63			`else`
64			`StackPt--; /* popped state must be TRUE */`
65			`Hiatus = TRUE;`
66			`break;`
67			`/* case NORMAL is not implemented as it represents normal line`
68			`processing. */`
69			`case IF_END: /* file ended with improperly nested IFD */`
70			`/* this code can't actually be reached at present`
71			`in a TRUE_BLOCK */`
72			`fatal("Error: file ended before IFD/IFND/ELSE/ENDIF");`
73			`break;`
74			`default: /* This code can't be reached at the present.`
75			`Logically would happen if EOF but handled`
76			`else where */`
77			`fatal("Can't get here from there.");`
78			`break;`
79			`}`
80			`else if (State == FALSE_BLOCK) /* statements not processed */`
81			`switch(Token) {`
82			`case IF_TRUE: /* doesn't make any diff. Just nest IFs */`
83			`case IF_FALSE:`
84			`IfStack[StackPt]=FALSE;`
85			`if (++StackPt > MAXIFD) {`
86			`StackPt = MAXIFD;`
87			`error("Error:IFD/IFND nested too deep");`
88			`}`
89			`if (Pass == 2 && Lflag && !N_page)`
90			`print_line();`
91			`Token = GetToken();`
92			`break;`
93			`case IF_ELSE:`
94			`/* if (Pass == 2 && Lflag && !N_page) */`
95			`/* print_line(); */`
96			`State = ELSE_TEST;`
97			`break;`
98			`case IF_ENDIF:`
99			`State = POP_TEST;`
100			`break;`
101			`case IF_END: /* file ended with improperly nested IFD */`
102			`fatal("Fatal Error: file ended before last ENDIF");`
103			`/* Fatal will exit assembler. Things are too`
104			`messed up. Include file handling is else where`
105			`and don't want to duplicate here. */`
106			`break;`
107			`case IF_NORMAL: /* normal line in a FALSE BLOCK */`
108			`if (Pass == 2 && Lflag && !N_page)`
109			`print_line();`
110			`Token = GetToken();`
111			`break;`
112			`default:`
113			`fatal("Fatal Error: file ended before last ENDIF");`
114			`/* must be EOF or something else terrible */`
115			`break;`
116			`}`
117			`else if (State == POP_TEST) { /* pop up outside nest state */`
118			`if (StackPt == 0) { /* bad IF nesting */`
119			`error("Error: ENDIF without IF");`
120			`if (Pass == 2 && Lflag && !N_page)`
121			`print_line();`
122			`State = TRUE;`
123			`}`
124			`else {`
125			`StackPt--; /* pop stack */`
126			`if (IfStack[StackPt] == TRUE) { /* back to normal */`
127			`/* had to come from FALSE block cuz TRUE block cannot`
128			`be inside FALSE block */`
129			`if (Pass == 2 && Lflag && !N_page)`
130			`print_line();`
131			`State = TRUE;`
132			`Hiatus = TRUE; /* sleep for normal line processing */`
133			`}`
134			`else { /* gotta be that stack == FALSE, still inside FALSE nest */`
135			`if (Pass == 2 && Lflag && !N_page)`
136			`print_line();`
137			`State = FALSE;`
138			`Token = GetToken();`
139			`}`
140			`}`
141			`}`
142			`else if (State == ELSE_TEST) { /* change state */`
143			`if (IfStack[StackPt-1] == TRUE) {`
144			`State = TRUE_BLOCK;`
145			`Hiatus = TRUE;`
146			`}`
147			`else`
148			`State = FALSE_BLOCK;`
149			`}`
150			`}`
151			`while (Hiatus == FALSE); /* loop if not exit */`
152			`}`
153
154
155			`/* GetToken() --- get another line from within False Block and extract token`
156			`as would be done in pseudo.c. Returns token id:`
157			`IF_TRUE IFD/IFND evaluated to TRUE`
158			`IF_FALSE IFD/IFND evaluated to FALSE`
159			`IF_ELSE ELSE pseudo op`
160			`IF_ENDIF ENDIF pseudo op`
161			`IF_END END pseudo op`
162			`IF_NORMAL none of the above, perhaps assy code`
163			`IF_EOF encountered end of file`
164			`This function exists because conditional assembly was added`
165			`as pseudo op rather than with key character ("%") and did`
166			`not want to disturb original software topology */`
167
168			`int GetToken() /* get another line and find token in it */`
169			`{ /* similar to make_pass() except one line at a time */`
170			`/* most variables & constants are global */`
171
172			`struct nlist *lookup();`
173
174			`#ifndef IBM`
175			`if (FGETS(Line,MAXBUF-1,Fd) == (char *)NULL)`
176			`#else`
177			`if (fgets(Line,MAXBUF,Fd) == (char *)NULL)`
178			`#endif`
179			`return(IF_EOF); /* banged into eof */`
180			`Line_num++;`
181			`P_force=0;`
182			`N_page=0;`
183			`if (!parse_line())`
184			`return(IF_NORMAL); /* comment line */`
185			`if (Op==EOS) / skipping over label, probably. */`
186			`return(IF_NORMAL); /* strcmp() returns 0 if arg1 is NULL string */`
187
188			`if (strcmp(Op,"ifd")==0)`
189			`return(eval_ifd());`
190			`else if (strcmp(Op,"ifnd")==0)`
191			`return(eval_ifnd());`
192			`else if (strcmp(Op,"else")==0)`
193			`return(IF_ELSE);`
194			`else if (strcmp(Op,"endif")==0)`
195			`return(IF_ENDIF);`
196			`else if (strcmp(Op,"end")==0)`
197			`return(IF_END);`
198			`else`
199			`return(IF_NORMAL); /* or might be garbage...but who cares?`
200			`This is FALSE BLOCK */`
201			`}`
202
203
204			`/*`
205			`* eval_ifd() --- evaluate an if define statement for TRUE or FALSE`
206			`*/`
207
208			`int`
209			`eval_ifd()`
210			`{`
211			`struct nlist np; / symbol structure */`
212
213			`if (*Operand==EOS) {`
214			`warn("No symbol for IFD");`
215			`return(IF_FALSE); /* nothing to check */`
216			`}`
217			`if ((np=lookup(Operand)) == NULL)`
218			`return(IF_FALSE); /* not defined at all...yet */`
219			`else`
220			`if(np->def2 == Pass)`
221			`return(IF_TRUE); /* defined for this pass */`
222
223			`return(IF_FALSE); /* not defined this pass */`
224			`}`
225
226			`/*`
227			`* eval_ifnd() --- evaluate an if not define statement for TRUE or FALSE`
228			`*/`
229
230			`int`
231			`eval_ifnd()`
232			`{`
233			`struct nlist np; / symbol structure */`
234
235			`if (*Operand==EOS) {`
236			`warn("No symbol for IFND");`
237			`return(IF_TRUE); /* nothing to check */`
238			`}`
239			`if ((np=lookup(Operand)) == NULL)`
240			`return(IF_TRUE); /* not defined at all...yet */`
241			`else`
242			`if(np->def2 == Pass)`
243			`return(IF_FALSE); /* defined for this pass */`
244
245			`return(IF_TRUE); /* not defined this pass */`
246			`}`

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[/] [System09/] [trunk/] [Tools/] [as09/] [ifd.c] - Blame information for rev 74