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/* cond.c - conditional assembly pseudo-ops, and .include
Copyright (C) 1990, 1991 Free Software Foundation, Inc.
This file is part of GAS, the GNU Assembler.
GAS is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
GAS is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GAS; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
#include "as.h"
#include "obstack.h"
/* This is allocated to grow and shrink as .ifdef/.endif pairs are scanned. */
struct obstack cond_obstack;
struct file_line {
char *logical_file;
int logical_line;
char *physical_file;
int physical_line;
}; /* file_line */
/* This is what we push and pop. */
struct conditional_frame {
struct file_line if_file_line; /* the source file & line number of the "if" */
struct file_line else_file_line; /* the source file & line of the "else" */
struct conditional_frame *previous_cframe;
int else_seen; /* have we seen an else yet? */
int ignoring; /* if we are currently ignoring input. */
int dead_tree; /* if a conditional at a higher level is ignoring input. */
}; /* conditional_frame */
#ifdef __STDC__
static void get_file_line(struct file_line *into);
static void initialize_cframe(struct conditional_frame *cframe);
static void set_file_line(struct file_line *from);
#else
static void get_file_line();
static void initialize_cframe();
static void set_file_line();
#endif
static struct conditional_frame *current_cframe = NULL;
void s_ifdef(arg)
int arg;
{
register char *name; /* points to name of symbol */
register struct symbol *symbolP; /* Points to symbol */
struct conditional_frame cframe;
SKIP_WHITESPACE(); /* Leading whitespace is part of operand. */
name = input_line_pointer;
if (!is_name_beginner(*name)) {
as_bad("invalid identifier for \".ifdef\"");
obstack_1grow(&cond_obstack, 0);
} else {
get_symbol_end();
++input_line_pointer;
symbolP = symbol_find(name);
initialize_cframe(&cframe);
cframe.ignoring = cframe.dead_tree && !((symbolP != 0) ^ arg);
current_cframe = (struct conditional_frame *) obstack_copy(&cond_obstack, &cframe, sizeof(cframe));
} /* if a valid identifyer name */
return;
} /* s_ifdef() */
void s_if(arg)
int arg;
{
expressionS operand;
struct conditional_frame cframe;
SKIP_WHITESPACE(); /* Leading whitespace is part of operand. */
expr(0, &operand);
if (operand.X_add_symbol != NULL
|| operand.X_subtract_symbol != NULL) {
as_bad("non-constant expression in \".if\" statement");
} /* bad condition */
/* If the above error is signaled, this will dispatch
using an undefined result. No big deal. */
initialize_cframe(&cframe);
cframe.ignoring = cframe.dead_tree || !((operand.X_add_number != 0) ^ arg);
current_cframe = (struct conditional_frame *) obstack_copy(&cond_obstack, &cframe, sizeof(cframe));
return;
} /* s_if() */
void s_endif(arg)
int arg;
{
struct conditional_frame *hold;
if (current_cframe == NULL) {
as_bad("\".endif\" without \".if\"");
} else {
hold = current_cframe;
current_cframe = current_cframe->previous_cframe;
obstack_free(&cond_obstack, hold);
} /* if one pop too many */
return;
} /* s_endif() */
void s_else(arg)
int arg;
{
if (current_cframe == NULL) {
as_bad(".else without matching .if - ignored");
} else if (current_cframe->else_seen) {
struct file_line hold;
as_bad("duplicate \"else\" - ignored");
get_file_line(&hold);
set_file_line(¤t_cframe->else_file_line);
as_bad("here is the previous \"else\".");
set_file_line(¤t_cframe->if_file_line);
as_bad("here is the matching \".if\".");
set_file_line(&hold);
} else {
get_file_line(¤t_cframe->else_file_line);
if (!current_cframe->dead_tree) {
current_cframe->ignoring = !current_cframe->ignoring;
} /* if not a dead tree */
current_cframe->else_seen = 1;
} /* if error else do it */
return;
} /* s_else() */
void s_ifeqs(arg)
int arg;
{
as_bad("ifeqs not implemented.");
return;
} /* s_ifeqs() */
void s_end(arg)
int arg;
{
return;
} /* s_end() */
int ignore_input() {
char *ptr = obstack_next_free (&cond_obstack);
/* We cannot ignore certain pseudo ops. */
if (input_line_pointer[-1] == '.'
&& ((input_line_pointer[0] == 'i'
&& (!strncmp (input_line_pointer, "if", 2)
|| !strncmp (input_line_pointer, "ifdef", 5)
|| !strncmp (input_line_pointer, "ifndef", 6)))
|| (input_line_pointer[0] == 'e'
&& (!strncmp (input_line_pointer, "else", 4)
|| !strncmp (input_line_pointer, "endif", 5))))) {
return 0;
}
return((current_cframe != NULL) && (current_cframe->ignoring));
} /* ignore_input() */
static void initialize_cframe(cframe)
struct conditional_frame *cframe;
{
memset(cframe, 0, sizeof(*cframe));
get_file_line(&(cframe->if_file_line));
cframe->previous_cframe = current_cframe;
cframe->dead_tree = current_cframe != NULL && current_cframe->ignoring;
return;
} /* initialize_cframe() */
static void get_file_line(into)
struct file_line *into;
{
extern char *logical_input_file;
extern char *physical_input_file;
extern int logical_input_line;
extern int physical_input_line;
into->logical_file = logical_input_file;
into->logical_line = logical_input_line;
into->physical_file = physical_input_file;
into->physical_line = physical_input_line;
return;
} /* get_file_line() */
static void set_file_line(from)
struct file_line *from;
{
extern char *logical_input_file;
extern char *physical_input_file;
extern int logical_input_line;
extern int physical_input_line;
logical_input_file = from->logical_file;
logical_input_line = from->logical_line;
physical_input_file = from->physical_file;
physical_input_line = from->physical_line;
return;
} /* set_file_line() */
/*
* Local Variables:
* fill-column: 131
* comment-column: 0
* End:
*/
/* end of cond.c */
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