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- /* $Header$ */
- /* S W I T C H - S T A T E M E N T A D M I N I S T R A T I O N */
- #include <em.h>
- #include "debug.h"
- #include "botch_free.h"
- #include "density.h"
- #include "Lpars.h"
- #include "idf.h"
- #include "label.h"
- #include "arith.h"
- #include "switch.h"
- #include "code.h"
- #include "storage.h"
- #include "assert.h"
- #include "expr.h"
- #include "type.h"
- extern char options[];
- #define compact(nr, low, up) (nr != 0 && (up - low) / nr <= (DENSITY - 1))
- static struct switch_hdr *switch_stack = 0;
- code_startswitch(expr)
- struct expr *expr;
- {
- /* Check the expression, stack a new case header and
- fill in the necessary fields.
- */
- register label l_table = text_label();
- register label l_break = text_label();
- register struct switch_hdr *sh = new_switch_hdr();
- int fund = any2arith(&expr, SWITCH); /* INT, LONG or DOUBLE */
-
- switch (fund) {
- case LONG:
- if (options['R'])
- warning("long in switch");
- break;
- case DOUBLE:
- error("float/double in switch");
- erroneous2int(&expr);
- break;
- }
-
- stat_stack(l_break, NO_LABEL);
- sh->sh_break = l_break;
- sh->sh_default = 0;
- sh->sh_table = l_table;
- sh->sh_nrofentries = 0;
- sh->sh_type = expr->ex_type; /* the expression switched */
- sh->sh_lowerbd = sh->sh_upperbd = (arith)0; /* immaterial ??? */
- sh->sh_entries = (struct case_entry *) 0; /* case-entry list */
- sh->next = switch_stack; /* push onto switch-stack */
- switch_stack = sh;
- code_expr(expr, RVAL, TRUE, NO_LABEL, NO_LABEL);
- /* evaluate the switch expr. */
- C_bra(l_table); /* goto start of switch_table */
- }
- code_endswitch()
- {
- register struct switch_hdr *sh = switch_stack;
- register label tablabel;
- register struct case_entry *ce;
- if (sh->sh_default == 0) /* no default occurred yet */
- sh->sh_default = sh->sh_break;
- C_bra(sh->sh_break); /* skip the switch table now */
- C_df_ilb(sh->sh_table); /* switch table entry */
- tablabel = data_label(); /* the rom must have a label */
- C_df_dlb(tablabel);
- C_rom_ilb(sh->sh_default);
- if (compact(sh->sh_nrofentries, sh->sh_lowerbd, sh->sh_upperbd)) {
- /* CSA */
- register arith val;
- C_rom_cst(sh->sh_lowerbd);
- C_rom_cst(sh->sh_upperbd - sh->sh_lowerbd);
- ce = sh->sh_entries;
- for (val = sh->sh_lowerbd; val <= sh->sh_upperbd; val++) {
- ASSERT(ce);
- if (val == ce->ce_value) {
- C_rom_ilb(ce->ce_label);
- ce = ce->next;
- }
- else
- C_rom_ilb(sh->sh_default);
- }
- C_lae_dlb(tablabel, (arith)0); /* perform the switch */
- C_csa(sh->sh_type->tp_size);
- }
- else { /* CSB */
- C_rom_cst((arith)sh->sh_nrofentries);
- for (ce = sh->sh_entries; ce; ce = ce->next) {
- /* generate the entries: value + prog.label */
- C_rom_cst(ce->ce_value);
- C_rom_ilb(ce->ce_label);
- }
- C_lae_dlb(tablabel, (arith)0); /* perform the switch */
- C_csb(sh->sh_type->tp_size);
- }
- C_df_ilb(sh->sh_break);
- switch_stack = sh->next; /* unstack the switch descriptor */
-
- /* free the allocated switch structure */
- ce = sh->sh_entries;
- while (ce) {
- register struct case_entry *tmp = ce->next;
- free_case_entry(ce);
- ce = tmp;
- }
- free_switch_hdr(sh);
- stat_unstack();
- }
- code_case(expr)
- struct expr *expr;
- {
- register arith val;
- register struct case_entry *ce;
- register struct switch_hdr *sh = switch_stack;
-
- if (sh == 0) {
- error("case statement not in switch");
- return;
- }
-
- if (expr->ex_flags & EX_ERROR) {
- /* is probably 0 anyway */
- return;
- }
-
- expr->ex_type = sh->sh_type;
- cut_size(expr);
-
- ce = new_case_entry();
- C_df_ilb(ce->ce_label = text_label());
- ce->ce_value = val = expr->VL_VALUE;
-
- if (sh->sh_entries == 0) {
- /* first case entry */
- ce->next = (struct case_entry *) 0;
- sh->sh_entries = ce;
- sh->sh_lowerbd = sh->sh_upperbd = val;
- sh->sh_nrofentries = 1;
- }
- else {
- /* second etc. case entry */
- /* find the proper place to put ce into the list */
- register struct case_entry *c1 = sh->sh_entries, *c2 = 0;
-
- if (val < sh->sh_lowerbd)
- sh->sh_lowerbd = val;
- else
- if (val > sh->sh_upperbd)
- sh->sh_upperbd = val;
- while (c1 && c1->ce_value < ce->ce_value) {
- c2 = c1;
- c1 = c1->next;
- }
- /* At this point three cases are possible:
- 1: c1 != 0 && c2 != 0:
- insert ce somewhere in the middle
- 2: c1 != 0 && c2 == 0:
- insert ce right after the head
- 3: c1 == 0 && c2 != 0:
- append ce to last element
- The case c1 == 0 && c2 == 0 cannot occur, since
- the list is guaranteed not to be empty.
- */
- if (c1) {
- if (c1->ce_value == ce->ce_value) {
- error("multiple case entry for value %ld",
- ce->ce_value);
- free_case_entry(ce);
- return;
- }
- if (c2) {
- ce->next = c2->next;
- c2->next = ce;
- }
- else {
- ce->next = sh->sh_entries;
- sh->sh_entries = ce;
- }
- }
- else {
- ASSERT(c2);
- ce->next = (struct case_entry *) 0;
- c2->next = ce;
- }
- (sh->sh_nrofentries)++;
- }
- }
- code_default()
- {
- register struct switch_hdr *sh = switch_stack;
- if (sh == 0) {
- error("default not in switch");
- return;
- }
- if (sh->sh_default != 0) {
- error("multiple entry for default in switch");
- return;
- }
- C_df_ilb(sh->sh_default = text_label());
- }
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