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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 1, 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. */
/* static const char rcsid[] = "$Id$"; */
#include "as.h"
#include "obstack.h"
void s_ifdef(arg)
int arg;
{
/* register char c; */
register char *name; /* points to name of symbol */
register struct symbol * symbolP; /* Points to symbol */
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);
/* ??? Should we try to optimize such that if we hit a .endif
before a .else, we don't need to push state? */
obstack_1grow(&cond_obstack, (symbolP != 0) ^ arg);
}
} /* s_ifdef() */
/* This is allocated to grow and shrink as .ifdef/.endif pairs
are scanned. When the top element is nonzero, it means
we should accept input. Otherwise, we should ignore input. */
struct obstack cond_obstack;
void s_if(arg)
int arg;
{
expressionS operand;
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");
/* If the above error is signaled, this will dispatch
using an undefined result. No big deal. */
obstack_1grow(&cond_obstack, (operand.X_add_number != 0) ^ arg);
} /* s_if() */
void s_endif(arg)
int arg;
{
char *base = obstack_base(&cond_obstack);
char *ptr = obstack_next_free(&cond_obstack);
if (ptr-1 == base) {
as_bad("unbalanced .endif");
} else {
obstack_free(&cond_obstack, ptr-1);
cond_obstack.object_base = base;
}
} /* s_endif() */
void s_else(arg)
int arg;
{
char *ptr = obstack_next_free(&cond_obstack);
if (ptr-1 == obstack_base(&cond_obstack)) {
as_bad(".else without matching .if");
} else {
ptr[-1] = !ptr[-1];
}
} /* s_else() */
void s_ifeqs(arg)
int arg;
{
as_bad("ifeqs not implemented.");
} /* s_ifeqs() */
void s_end(arg)
int arg;
{
;
} /* s_end() */
int ignore_input() {
char *ptr = obstack_next_free (&cond_obstack);
/* We cannot ignore certain pseudo ops. */
if (input_line_pointer[-1] == '.')
{
if (input_line_pointer[0] == 'i'
&& (!strncmp (input_line_pointer, "if", 2)
|| !strncmp (input_line_pointer, "ifdef", 5)
|| !strncmp (input_line_pointer, "ifndef", 6)))
return 0;
if (input_line_pointer[0] == 'e'
&& (!strncmp (input_line_pointer, "else", 4)
|| !strncmp (input_line_pointer, "endif", 5)))
return 0;
}
return (ptr[-1] == 0);
} /* ignore_input() */
/* end of cond.c */
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