129 lines
3.4 KiB
C
129 lines
3.4 KiB
C
/* cond.c - conditional assembly pseudo-ops, and .include
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Copyright (C) 1990, 1991 Free Software Foundation, Inc.
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This file is part of GAS, the GNU Assembler.
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GAS is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 1, or (at your option)
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any later version.
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GAS is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GAS; see the file COPYING. If not, write to
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the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
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/* static const char rcsid[] = "$Id$"; */
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#include "as.h"
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#include "obstack.h"
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void s_ifdef(arg)
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int arg;
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{
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/* register char c; */
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register char *name; /* points to name of symbol */
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register struct symbol * symbolP; /* Points to symbol */
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SKIP_WHITESPACE(); /* Leading whitespace is part of operand. */
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name = input_line_pointer;
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if (!is_name_beginner(*name)) {
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as_bad("invalid identifier for .ifdef");
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obstack_1grow (&cond_obstack, 0);
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} else {
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get_symbol_end();
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++input_line_pointer;
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symbolP = symbol_find(name);
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/* ??? Should we try to optimize such that if we hit a .endif
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before a .else, we don't need to push state? */
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obstack_1grow(&cond_obstack, (symbolP != 0) ^ arg);
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}
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} /* s_ifdef() */
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/* This is allocated to grow and shrink as .ifdef/.endif pairs
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are scanned. When the top element is nonzero, it means
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we should accept input. Otherwise, we should ignore input. */
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struct obstack cond_obstack;
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void s_if(arg)
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int arg;
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{
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expressionS operand;
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SKIP_WHITESPACE(); /* Leading whitespace is part of operand. */
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expr(0, &operand);
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if (operand.X_add_symbol != NULL
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|| operand.X_subtract_symbol != NULL)
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as_bad("non-constant expression in .if statement");
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/* If the above error is signaled, this will dispatch
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using an undefined result. No big deal. */
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obstack_1grow(&cond_obstack, (operand.X_add_number != 0) ^ arg);
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} /* s_if() */
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void s_endif(arg)
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int arg;
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{
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char *base = obstack_base(&cond_obstack);
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char *ptr = obstack_next_free(&cond_obstack);
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if (ptr-1 == base) {
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as_bad("unbalanced .endif");
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} else {
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obstack_free(&cond_obstack, ptr-1);
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cond_obstack.object_base = base;
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}
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} /* s_endif() */
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void s_else(arg)
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int arg;
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{
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char *ptr = obstack_next_free(&cond_obstack);
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if (ptr-1 == obstack_base(&cond_obstack)) {
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as_bad(".else without matching .if");
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} else {
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ptr[-1] = !ptr[-1];
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}
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} /* s_else() */
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void s_ifeqs(arg)
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int arg;
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{
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as_bad("ifeqs not implemented.");
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} /* s_ifeqs() */
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void s_end(arg)
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int arg;
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{
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;
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} /* s_end() */
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int ignore_input() {
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char *ptr = obstack_next_free (&cond_obstack);
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/* We cannot ignore certain pseudo ops. */
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if (input_line_pointer[-1] == '.')
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{
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if (input_line_pointer[0] == 'i'
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&& (!strncmp (input_line_pointer, "if", 2)
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|| !strncmp (input_line_pointer, "ifdef", 5)
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|| !strncmp (input_line_pointer, "ifndef", 6)))
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return 0;
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if (input_line_pointer[0] == 'e'
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&& (!strncmp (input_line_pointer, "else", 4)
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|| !strncmp (input_line_pointer, "endif", 5)))
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return 0;
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}
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return (ptr[-1] == 0);
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} /* ignore_input() */
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/* end of cond.c */
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