date and time created 80/08/27 19:54:42 by peter

SCCS-vsn: usr.bin/pascal/src/case.c 1.1

diff --git a/usr/src/usr.bin/pascal/src/case.c b/usr/src/usr.bin/pascal/src/case.c
new file mode 100644 (file)
index 0000000..8f6100f
--- /dev/null
+++ b/usr/src/usr.bin/pascal/src/case.c
@@ -0,0 +1,187 @@
+/* Copyright (c) 1979 Regents of the University of California */
+
+static char sccsid[] = "@(#)case.c 1.1 %G%";
+
+#include "whoami.h"
+#include "0.h"
+#include "tree.h"
+#include "opcode.h"
+
+/*
+ * The structure used to
+ * hold information about
+ * each case label.
+ */
+struct ct {
+       long    clong;
+       int     cline;
+};
+
+#ifdef OBJ
+/*
+ * Caseop generates the
+ * pascal case statement code
+ */
+caseop(r)
+       int *r;
+{
+       register struct nl *p;
+       register struct ct *ctab;
+       register *cs;
+       int *cl;
+       double low, high;
+       short *brtab;
+       char *brtab0;
+       char *csend;
+       int w, i, j, m, n;
+       int nr, goc;
+
+       goc = gocnt;
+       /*
+        * Obtain selector attributes:
+        *      p       type
+        *      w       width
+        *      low     lwb(p)
+        *      high    upb(p)
+        */
+       p = rvalue((int *) r[2], NLNIL , RREQ );
+       if (p != NIL) {
+               if (isnta(p, "bcsi")) {
+                       error("Case selectors cannot be %ss", nameof(p));
+                       p = NIL;
+               } else {
+                       cl = p;
+                       if (p->class != RANGE)
+                               cl = p->type;
+                       if (cl == NIL)
+                               p = NIL;
+                       else {
+                               w = width(p);
+#ifdef DEBUG
+                               if (hp21mx)
+                                       w = 2;
+#endif
+                               low = cl->range[0];
+                               high = cl->range[1];
+                       }
+               }
+       }
+       /*
+        * Count # of cases
+        */
+       n = 0;
+       for (cl = r[3]; cl != NIL; cl = cl[2]) {
+               cs = cl[1];
+               if (cs == NIL)
+                       continue;
+               for (cs = cs[2]; cs != NIL; cs = cs[2])
+                       n++;
+       }
+       /*
+        * Allocate case table space
+        */
+       ctab = i = malloc(n * sizeof *ctab);
+       if (i == -1) {
+               error("Ran out of memory (case)");
+               pexit(DIED);
+       }
+       /*
+        * Check the legality of the
+        * labels and count the number
+        * of good labels
+        */
+       m = 0;
+       for (cl = r[3]; cl != NIL; cl = cl[2]) {
+               cs = cl[1];
+               if (cs == NIL)
+                       continue;
+               line = cs[1];
+               for (cs = cs[2]; cs != NIL; cs = cs[2]) {
+                       gconst(cs[1]);
+                       if (p == NIL || con.ctype == NIL)
+                               continue;
+                       if (incompat(con.ctype, p, NIL )) {
+                               cerror("Case label type clashed with case selector expression type");
+                               continue;
+                       }
+                       if (con.crval < low || con.crval > high) {
+                               error("Case label out of range");
+                               continue;
+                       }
+                       ctab[m].clong = con.crval;
+                       ctab[m].cline = line;
+                       m++;
+               }
+       }
+
+       /*
+        * Check for duplicate labels
+        */
+       for (i = 0; i < m; i++)
+               for (j = 0; j < m; j++)
+                       if (ctab[i].clong == ctab[j].clong) {
+                               if (i == j)
+                                       continue;
+                               if (j < i)
+                                       break;
+                               error("Multiply defined label in case, lines %d and %d", ctab[i].cline, ctab[j].cline);
+                       }
+       /*
+        * Put out case operator and
+        * leave space for the
+        * branch table
+        */
+       if (p != NIL) {
+               put(2, O_CASE1OP + (w >> 1), n);
+               brtab = brtab0 = lc;
+               putspace(n * 2);
+               put(1, O_CASEBEG);
+               for (i=0; i<m; i++)
+                       put( 2 , O_CASE1 + (w >> 1), ctab[i].clong);
+               put(1, O_CASEEND);
+       }
+       csend = getlab();
+       put(2, O_TRA, csend);
+       /*
+        * Free the case
+        * table space.
+        */
+       free(ctab);
+       /*
+        * Generate code for each
+        * statement. Patch branch
+        * table to beginning of each
+        * statement and follow each
+        * statement with a branch back
+        * to the TRA above.
+        */
+       nr = 1;
+       for (cl = r[3]; cl != NIL; cl = cl[2]) {
+               cs = cl[1];
+               if (cs == NIL)
+                       continue;
+               if (p != NIL)
+                       for (cs = cs[2]; cs != NIL; cs = cs[2]) {
+                               patchfil(brtab - 1, lc - brtab0, 1);
+                               brtab++;
+                       }
+               cs = cl[1];
+               putcnt();
+               level++;
+               statement(cs[3]);
+               nr &= noreach;
+               noreach = 0;
+               put(2, O_TRA, csend);
+               level--;
+               if (gotos[cbn])
+                       ungoto();
+       }
+       /*
+        * Patch the termination branch
+        */
+       patch(csend);
+       noreach = nr;
+       if (goc != gocnt)
+               putcnt();
+}
+#endif OBJ