| 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 November 1978 |
| 8 | */ |
| 9 | |
| 10 | #include "whoami" |
| 11 | #include "0.h" |
| 12 | #include "tree.h" |
| 13 | #include "opcode.h" |
| 14 | |
| 15 | /* |
| 16 | * The structure used to |
| 17 | * hold information about |
| 18 | * each case label. |
| 19 | */ |
| 20 | struct ct { |
| 21 | long clong; |
| 22 | int cline; |
| 23 | }; |
| 24 | |
| 25 | /* |
| 26 | * Caseop generates the |
| 27 | * pascal case statement code |
| 28 | */ |
| 29 | caseop(r) |
| 30 | int *r; |
| 31 | { |
| 32 | register struct nl *p; |
| 33 | register struct ct *ctab; |
| 34 | register *cs; |
| 35 | int *cl; |
| 36 | double low, high; |
| 37 | short *brtab; |
| 38 | char *brtab0; |
| 39 | char *csend; |
| 40 | int w, i, j, m, n; |
| 41 | int nr, goc; |
| 42 | |
| 43 | goc = gocnt; |
| 44 | /* |
| 45 | * Obtain selector attributes: |
| 46 | * p type |
| 47 | * w width |
| 48 | * low lwb(p) |
| 49 | * high upb(p) |
| 50 | */ |
| 51 | p = rvalue((int *) r[2], NLNIL); |
| 52 | if (p != NIL) { |
| 53 | if (isnta(p, "bcsi")) { |
| 54 | error("Case selectors cannot be %ss", nameof(p)); |
| 55 | p = NIL; |
| 56 | } else { |
| 57 | cl = p; |
| 58 | if (p->class != RANGE) |
| 59 | cl = p->type; |
| 60 | if (cl == NIL) |
| 61 | p = NIL; |
| 62 | else { |
| 63 | w = width(p); |
| 64 | #ifdef DEBUG |
| 65 | if (hp21mx) |
| 66 | w = 2; |
| 67 | #endif |
| 68 | low = cl->range[0]; |
| 69 | high = cl->range[1]; |
| 70 | } |
| 71 | } |
| 72 | } |
| 73 | /* |
| 74 | * Count # of cases |
| 75 | */ |
| 76 | n = 0; |
| 77 | for (cl = r[3]; cl != NIL; cl = cl[2]) { |
| 78 | cs = cl[1]; |
| 79 | if (cs == NIL) |
| 80 | continue; |
| 81 | for (cs = cs[2]; cs != NIL; cs = cs[2]) |
| 82 | n++; |
| 83 | } |
| 84 | /* |
| 85 | * Allocate case table space |
| 86 | */ |
| 87 | ctab = i = malloc(n * sizeof *ctab); |
| 88 | if (i == -1) { |
| 89 | error("Ran out of memory (case)"); |
| 90 | pexit(DIED); |
| 91 | } |
| 92 | /* |
| 93 | * Check the legality of the |
| 94 | * labels and count the number |
| 95 | * of good labels |
| 96 | */ |
| 97 | m = 0; |
| 98 | for (cl = r[3]; cl != NIL; cl = cl[2]) { |
| 99 | cs = cl[1]; |
| 100 | if (cs == NIL) |
| 101 | continue; |
| 102 | line = cs[1]; |
| 103 | for (cs = cs[2]; cs != NIL; cs = cs[2]) { |
| 104 | gconst(cs[1]); |
| 105 | if (p == NIL || con.ctype == NIL) |
| 106 | continue; |
| 107 | if (incompat(con.ctype, p, NIL)) { |
| 108 | cerror("Case label type clashed with case selector expression type"); |
| 109 | continue; |
| 110 | } |
| 111 | if (con.crval < low || con.crval > high) { |
| 112 | error("Case label out of range"); |
| 113 | continue; |
| 114 | } |
| 115 | ctab[m].clong = con.crval; |
| 116 | ctab[m].cline = line; |
| 117 | m++; |
| 118 | } |
| 119 | } |
| 120 | |
| 121 | /* |
| 122 | * Check for duplicate labels |
| 123 | */ |
| 124 | for (i = 0; i < m; i++) |
| 125 | for (j = 0; j < m; j++) |
| 126 | if (ctab[i].clong == ctab[j].clong) { |
| 127 | if (i == j) |
| 128 | continue; |
| 129 | if (j < i) |
| 130 | break; |
| 131 | error("Multiply defined label in case, lines %d and %d", ctab[i].cline, ctab[j].cline); |
| 132 | } |
| 133 | /* |
| 134 | * Put out case operator and |
| 135 | * leave space for the |
| 136 | * branch table |
| 137 | */ |
| 138 | if (p != NIL) { |
| 139 | put2(O_CASE1OP + (w >> 1), n); |
| 140 | brtab = brtab0 = lc; |
| 141 | putspace(n * 2); |
| 142 | put1(O_CASEBEG); |
| 143 | for (i=0; i<m; i++) |
| 144 | put( 3 , O_CASE1 + (w >> 1), ctab[i].clong); |
| 145 | put1(O_CASEEND); |
| 146 | } |
| 147 | csend = getlab(); |
| 148 | put2(O_TRA, csend); |
| 149 | /* |
| 150 | * Free the case |
| 151 | * table space. |
| 152 | */ |
| 153 | free(ctab); |
| 154 | /* |
| 155 | * Generate code for each |
| 156 | * statement. Patch branch |
| 157 | * table to beginning of each |
| 158 | * statement and follow each |
| 159 | * statement with a branch back |
| 160 | * to the TRA above. |
| 161 | */ |
| 162 | nr = 1; |
| 163 | for (cl = r[3]; cl != NIL; cl = cl[2]) { |
| 164 | cs = cl[1]; |
| 165 | if (cs == NIL) |
| 166 | continue; |
| 167 | if (p != NIL) |
| 168 | for (cs = cs[2]; cs != NIL; cs = cs[2]) { |
| 169 | patchfil(brtab - 1, lc - brtab0, 1); |
| 170 | brtab++; |
| 171 | } |
| 172 | cs = cl[1]; |
| 173 | putcnt(); |
| 174 | level++; |
| 175 | statement(cs[3]); |
| 176 | nr &= noreach; |
| 177 | noreach = 0; |
| 178 | put2(O_TRA, csend); |
| 179 | level--; |
| 180 | if (gotos[cbn]) |
| 181 | ungoto(); |
| 182 | } |
| 183 | /* |
| 184 | * Patch the termination branch |
| 185 | */ |
| 186 | patch(csend); |
| 187 | noreach = nr; |
| 188 | if (goc != gocnt) |
| 189 | putcnt(); |
| 190 | } |