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220 lines
5.7 KiB
C
220 lines
5.7 KiB
C
/* cond.c - conditional assembly pseudo-ops, and .include
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Copyright (C) 1990, 1991, 1992, 1993 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 2, 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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#ifndef lint
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static char rcsid[] = "$Id: cond.c,v 1.2 1994/12/23 22:36:03 nate Exp $";
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#endif
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#include "as.h"
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#include "obstack.h"
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/* This is allocated to grow and shrink as .ifdef/.endif pairs are scanned. */
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struct obstack cond_obstack;
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struct file_line
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{
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char *file;
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unsigned int line;
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}; /* file_line */
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/* This is what we push and pop. */
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struct conditional_frame
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{
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struct file_line if_file_line; /* the source file & line number of the "if" */
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struct file_line else_file_line; /* the source file & line of the "else" */
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struct conditional_frame *previous_cframe;
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int else_seen; /* have we seen an else yet? */
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int ignoring; /* if we are currently ignoring input. */
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int dead_tree; /* if a conditional at a higher level is ignoring input. */
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}; /* conditional_frame */
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static void initialize_cframe PARAMS ((struct conditional_frame *cframe));
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static struct conditional_frame *current_cframe = NULL;
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void
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s_ifdef (arg)
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int arg;
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{
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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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struct conditional_frame cframe;
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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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{
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as_bad ("invalid identifier for \".ifdef\"");
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obstack_1grow (&cond_obstack, 0);
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}
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else
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{
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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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initialize_cframe (&cframe);
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cframe.ignoring = cframe.dead_tree || !((symbolP != 0) ^ arg);
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current_cframe = (struct conditional_frame *) obstack_copy (&cond_obstack, &cframe, sizeof (cframe));
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} /* if a valid identifyer name */
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return;
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} /* s_ifdef() */
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void
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s_if (arg)
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int arg;
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{
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expressionS operand;
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struct conditional_frame cframe;
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SKIP_WHITESPACE (); /* Leading whitespace is part of operand. */
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expression (&operand);
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#ifdef notyet
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if (operand.X_op != O_constant)
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as_bad ("non-constant expression in \".if\" statement");
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#else
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if (operand.X_add_symbol != NULL || operand.X_subtract_symbol != NULL) {
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as_bad("non-constant expression in \".if\" statement");
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} /* bad condition */
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#endif
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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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initialize_cframe (&cframe);
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cframe.ignoring = cframe.dead_tree || !((operand.X_add_number != 0) ^ arg);
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current_cframe = (struct conditional_frame *) obstack_copy (&cond_obstack, &cframe, sizeof (cframe));
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return;
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} /* s_if() */
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void
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s_endif (arg)
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int arg;
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{
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struct conditional_frame *hold;
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if (current_cframe == NULL)
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{
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as_bad ("\".endif\" without \".if\"");
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}
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else
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{
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hold = current_cframe;
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current_cframe = current_cframe->previous_cframe;
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obstack_free (&cond_obstack, hold);
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} /* if one pop too many */
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return;
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} /* s_endif() */
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void
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s_else (arg)
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int arg;
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{
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if (current_cframe == NULL)
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{
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as_bad (".else without matching .if - ignored");
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}
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else if (current_cframe->else_seen)
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{
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as_bad ("duplicate \"else\" - ignored");
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as_bad_where (current_cframe->else_file_line.file,
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current_cframe->else_file_line.line,
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"here is the previous \"else\"");
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as_bad_where (current_cframe->if_file_line.file,
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current_cframe->if_file_line.line,
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"here is the previous \"if\"");
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}
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else
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{
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as_where (¤t_cframe->else_file_line.file,
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¤t_cframe->else_file_line.line);
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if (!current_cframe->dead_tree)
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{
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current_cframe->ignoring = !current_cframe->ignoring;
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} /* if not a dead tree */
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current_cframe->else_seen = 1;
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} /* if error else do it */
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return;
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} /* s_else() */
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void
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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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return;
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} /* s_ifeqs() */
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void
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s_end (arg)
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int arg;
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{
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return;
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} /* s_end() */
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int
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ignore_input ()
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{
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/* We cannot ignore certain pseudo ops. */
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if (input_line_pointer[-1] == '.'
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&& ((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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|| (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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{
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return 0;
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}
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return ((current_cframe != NULL) && (current_cframe->ignoring));
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} /* ignore_input() */
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static void
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initialize_cframe (cframe)
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struct conditional_frame *cframe;
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{
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memset (cframe, 0, sizeof (*cframe));
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as_where (&cframe->if_file_line.file,
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&cframe->if_file_line.line);
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cframe->previous_cframe = current_cframe;
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cframe->dead_tree = current_cframe != NULL && current_cframe->ignoring;
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return;
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} /* initialize_cframe() */
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/*
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* Local Variables:
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* fill-column: 131
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* comment-column: 0
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* End:
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*/
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/* end of cond.c */
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