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1.1 root 1: /* Copyright (c) 1979 Regents of the University of California */
2: #
3: /*
4: * pi - Pascal interpreter code translator
5: *
6: * Charles Haley, Bill Joy UCB
7: * Version 1.2 January 1979
8: *
9: *
10: * pxp - Pascal execution profiler
11: *
12: * Bill Joy UCB
13: * Version 1.2 January 1979
14: */
15:
16: #include "0.h"
17: #include "yy.h"
18:
19: /*
20: * Parser for 'yacc' output.
21: * Specifially Modified for Berkeley Pascal
22: */
23:
24: int yystate; /* Current parser state */
25: int *yypv;
26: unsigned yytshifts 1; /* Number of "true" shifts */
27:
28: /*
29: * Parse Tables
30: */
31: int yygo[];
32: int yypgo[];
33: int yyr1[];
34: int yyr2[];
35: int yyact[];
36: int yypact[];
37:
38: /*
39: * Parse and parallel semantic stack
40: */
41: int yyv[MAXDEPTH];
42: int yys[MAXDEPTH];
43:
44: /*
45: * This routine parses the input stream, and
46: * returns if it accepts, or if an unrecoverable syntax
47: * error is encountered.
48: */
49: yyparse()
50: {
51: register int *ps, n, *p;
52: int paniced, *panicps, idfail;
53:
54: yystate = 0;
55: yychar = yylex();
56: OY.Yychar = -1;
57: yyshifts = 3;
58: paniced = 0;
59: ps = &yys[0]-1;
60: yypv = &yyv[0]-1;
61: #ifdef PXP
62: yypw = &yyw[0]-1;
63: #endif
64:
65: stack:
66: /*
67: * Push new state and value.
68: */
69: if (yypv >= &yyv[MAXDEPTH-1]) {
70: yerror("Parse stack overflow");
71: pexit(DIED);
72: }
73: *++ps = yystate;
74: *++yypv = yyval;
75: #ifdef PXP
76: yypw++;
77: #endif
78: newstate:
79: /*
80: * Locate parsing actions for the
81: * new parser state.
82: */
83: p = &yyact[ yypact[yystate+1] ];
84: actn:
85: /*
86: * Search the parse actions table
87: * for something useful to do.
88: * While n is non-positive, it is the negation
89: * of the token we are testing for.
90: */
91: #ifdef PI
92: if ((n = *p++) <= 0) {
93: if (yychar < 0)
94: yychar = yylex();
95: do
96: if ((n =+ yychar) != 0)
97: p++;
98: while ((n = *p++) <= 0);
99: }
100: #else
101: while ((n = *p++) <= 0)
102: if ((n =+ yychar) != 0)
103: p++;
104: #endif
105: switch (n >> 12) {
106:
107: /*
108: * Shift.
109: */
110: case 2:
111: #ifdef PXP
112: yypw[1].Wseqid = yyseqid;
113: yypw[1].Wcol = yycol;
114: #endif
115: OYcopy();
116: yystate = n & 07777;
117: yyval = yylval;
118: #ifdef PI
119: yychar = -1;
120: #else
121: yychar = yylex();
122: #endif
123: yyshifts++;
124: yytshifts++;
125: goto stack;
126:
127: /*
128: * Reduce.
129: */
130: case 3:
131: n =& 07777;
132: N = yyr2[n];
133: if (N == 1 && OY.Yychar == YID && !yyEactr(n, yypv[0])) {
134: idfail = 1;
135: goto errin;
136: }
137: OY.Yychar = -1;
138: ps =- N;
139: yypv =- N;
140: #ifdef PXP
141: yypw =- N;
142: #endif
143: yyval = yypv[1];
144: yyactr(n);
145: /*
146: * Use goto table to find next state.
147: */
148: p = &yygo[yypgo[yyr1[n]]];
149: while (*p != *ps && *p >= 0)
150: p =+ 2;
151: yystate = p[1];
152: goto stack;
153:
154: /*
155: * Accept.
156: */
157: case 4:
158: return;
159:
160: /*
161: * Error.
162: */
163: case 1:
164: idfail = 0;
165: errin:
166: if ((paniced || yyshifts != 0) && yyrecover(ps, idfail)) {
167: paniced = 0;
168: ps = Ps;
169: yystate = *ps;
170: goto newstate;
171: }
172: /*
173: * Find a state where 'error' is a
174: * legal shift action.
175: */
176: if (paniced && yyshifts <= 0 && ps >= panicps) {
177: yypv =- (ps - panicps) + 1;
178: #ifdef PXP
179: yypw =- (ps - panicps) + 1;
180: #endif
181: ps = panicps - 1;
182: }
183: while (ps >= yys) {
184: for (p = &yyact[ yypact[*ps+1] ] ; *p <= 0; p=+ 2)
185: if (*p == -256) {
186: panicps = ps;
187: yystate= p[1] & 07777;
188: yyOshifts = yyshifts;
189: yyshifts = 0;
190: paniced = 1;
191: goto stack;
192: }
193: --ps;
194: --yypv;
195: #ifdef PXP
196: --yypw;
197: #endif
198: #ifdef PI
199: if (OY.Yychar != YID)
200: syneflg++;
201: #endif
202: OY.Yychar = -1;
203: }
204: if (yychar == YEOF)
205: yyunexeof();
206: if (yystate == 1)
207: yyexeof();
208: yerror("Unrecoverable syntax error - QUIT");
209: return;
210: }
211: panic("yyparse");
212: }
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