247 lines
6.1 KiB
C
247 lines
6.1 KiB
C
/*
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* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
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* See the copyright notice in the ACK home directory, in the file "Copyright".
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*/
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/* $Header$ */
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/* 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 */
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#include "lint.h"
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#ifndef LINT
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#include <em.h>
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#else
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#include "l_em.h"
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#endif LINT
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#include "debug.h"
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#include "botch_free.h"
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#include <alloc.h>
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#include "density.h"
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#include "Lpars.h"
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#include "idf.h"
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#include "label.h"
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#include <flt_arith.h>
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#include "arith.h"
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#include "switch.h"
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#include "code.h"
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#include "assert.h"
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#include "expr.h"
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#include "type.h"
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#include "sizes.h"
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extern char options[];
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int density = DENSITY;
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compact(nr, low, up)
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arith low, up;
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{
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/* Careful! up - low might not fit in an arith. And then,
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the test "up-low < 0" might also not work to detect this
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situation! Or is this just a bug in the M68020/M68000?
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*/
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arith diff = up - low;
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return (nr == 0 || (diff >= 0 && diff / nr <= (density - 1)));
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}
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static struct switch_hdr *switch_stack = 0;
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/* (EB 86.05.20) The following rules hold for switch statements:
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- the expression E in "switch(E)" shall have integral type (3.6.4.2)
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- the expression E in "case E:" is converted to the promoted type
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of the controlling expression
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For simplicity, we suppose int_size == word_size.
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*/
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code_startswitch(expp)
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struct expr **expp;
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{
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/* Check the expression, stack a new case header and
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fill in the necessary fields.
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*/
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register label l_table = text_label();
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register label l_break = text_label();
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register struct switch_hdr *sh = new_switch_hdr();
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int fund = any2arith(expp, SWITCH);
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/* INT, LONG, FLOAT, DOUBLE or LNGDBL */
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switch (fund) {
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case FLOAT:
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case DOUBLE:
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case LNGDBL:
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error("floating point type in switch");
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erroneous2int(expp);
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break;
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}
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stack_stmt(l_break, NO_LABEL);
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sh->sh_break = l_break;
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/* sh->sh_default = 0; */
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sh->sh_table = l_table;
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/* sh->sh_nrofentries = 0; */
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sh->sh_type = (*expp)->ex_type; /* the expression switched */
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/* sh->sh_entries = (struct case_entry *) 0; /* case-entry list */
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sh->sh_expr = *expp;
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#ifdef LINT
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code_expr(sh->sh_expr, RVAL, TRUE, NO_LABEL, NO_LABEL);
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#endif
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sh->next = switch_stack; /* push onto switch-stack */
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switch_stack = sh;
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C_bra(l_table); /* goto start of switch_table */
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}
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extern char *long2str();
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code_endswitch()
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{
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register struct switch_hdr *sh = switch_stack;
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register label tablabel;
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register struct case_entry *ce;
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arith size = sh->sh_type->tp_size;
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if (sh->sh_default == 0) /* no default occurred yet */
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sh->sh_default = sh->sh_break;
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C_bra(sh->sh_break); /* skip the switch table now */
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C_df_ilb(sh->sh_table); /* switch table entry */
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/* evaluate the switch expr. */
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#ifndef LINT
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code_expr(sh->sh_expr, RVAL, TRUE, NO_LABEL, NO_LABEL);
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#endif
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if (sh->sh_nrofentries <= 1) {
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if (sh->sh_nrofentries) {
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load_cst(sh->sh_lowerbd, size);
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C_cms(size);
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C_zeq(sh->sh_entries->ce_label);
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}
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else C_asp(size);
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C_bra(sh->sh_default);
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}
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else {
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tablabel = data_label(); /* the rom must have a label */
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C_df_dlb(tablabel);
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C_rom_ilb(sh->sh_default);
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if (compact(sh->sh_nrofentries, sh->sh_lowerbd, sh->sh_upperbd)) {
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/* CSA */
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register arith val;
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C_rom_icon(long2str((long)sh->sh_lowerbd,10), size);
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C_rom_icon(long2str((long)(sh->sh_upperbd - sh->sh_lowerbd),10),
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size);
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ce = sh->sh_entries;
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for (val = sh->sh_lowerbd; val <= sh->sh_upperbd; val++) {
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ASSERT(ce);
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if (val == ce->ce_value) {
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C_rom_ilb(ce->ce_label);
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ce = ce->next;
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}
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else
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C_rom_ilb(sh->sh_default);
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}
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C_lae_dlb(tablabel, (arith)0); /* perform the switch */
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C_csa(size);
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}
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else { /* CSB */
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C_rom_icon(long2str((long)sh->sh_nrofentries,10),size);
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for (ce = sh->sh_entries; ce; ce = ce->next) {
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/* generate the entries: value + prog.label */
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C_rom_icon(long2str((long)ce->ce_value,10),size);
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C_rom_ilb(ce->ce_label);
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}
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C_lae_dlb(tablabel, (arith)0); /* perform the switch */
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C_csb(size);
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}
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}
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C_df_ilb(sh->sh_break);
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switch_stack = sh->next; /* unstack the switch descriptor */
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for (ce = sh->sh_entries; ce;) { /* free allocated switch structure */
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register struct case_entry *tmp = ce->next;
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free_case_entry(ce);
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ce = tmp;
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}
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free_switch_hdr(sh);
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unstack_stmt();
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}
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code_case(expr)
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struct expr *expr;
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{
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register arith val;
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register struct case_entry *ce;
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register struct switch_hdr *sh = switch_stack;
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ASSERT(is_cp_cst(expr));
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if (sh == 0) {
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error("case statement not in switch");
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return;
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}
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if (expr->ex_flags & EX_ERROR) /* is probably 0 anyway */
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return;
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ch3cast(&expr, CASE, sh->sh_type);
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ce = new_case_entry();
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C_df_ilb(ce->ce_label = text_label());
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ce->ce_value = val = expr->VL_VALUE;
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if (sh->sh_entries == 0) { /* first case entry */
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/* ce->next = (struct case_entry *) 0; */
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sh->sh_entries = ce;
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sh->sh_lowerbd = sh->sh_upperbd = val;
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sh->sh_nrofentries = 1;
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}
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else { /* second etc. case entry; put ce into proper place */
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register struct case_entry *c1 = sh->sh_entries, *c2 = 0;
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if (val < sh->sh_lowerbd)
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sh->sh_lowerbd = val;
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else
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if (val > sh->sh_upperbd)
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sh->sh_upperbd = val;
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while (c1 && c1->ce_value < ce->ce_value) {
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c2 = c1;
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c1 = c1->next;
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}
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/* At this point three cases are possible:
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1: c1 != 0 && c2 != 0: insert ce somewhere in the middle
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2: c1 != 0 && c2 == 0: insert ce right after the head
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3: c1 == 0 && c2 != 0: append ce to last element
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The case c1 == 0 && c2 == 0 cannot occur, since
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the list is guaranteed to be non-empty.
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*/
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if (c1) {
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if (c1->ce_value == ce->ce_value) {
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error("multiple case entry for value %ld",
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ce->ce_value);
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free_case_entry(ce);
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return;
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}
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if (c2) {
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ce->next = c2->next;
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c2->next = ce;
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}
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else {
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ce->next = sh->sh_entries;
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sh->sh_entries = ce;
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}
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}
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else {
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ASSERT(c2);
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ce->next = (struct case_entry *) 0;
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c2->next = ce;
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}
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(sh->sh_nrofentries)++;
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}
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}
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code_default()
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{
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register struct switch_hdr *sh = switch_stack;
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if (sh == 0) {
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error("default statement not in switch");
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return;
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}
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if (sh->sh_default != 0) {
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error("multiple entry for default in switch");
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return;
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}
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C_df_ilb(sh->sh_default = text_label());
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}
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