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Fix crash on listing when nested noexpand macros are used Macros flagged noexpand were causing a segfault during listing. The problem was incorrect accounting for nesting levels for noexpand macros causing the listing handler to fall off the end of the program in certain circumstances and in other circumstances it would fail to suppress expansion. Both the segfault in the case of misbehaviour and the misbhaviour itself are corrected with this update. If you do not use nested noexpand macros, this bug has no effect.
author William Astle <lost@l-w.ca>
date Sat, 25 May 2013 13:35:46 -0600
parents bc25269d96bc
children d399df78e1ab
line wrap: on
line source

/*
lwasm.c

Copyright © 2010 William Astle

This file is part of LWTOOLS.

LWTOOLS 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 3 of the License, or (at your option) any later
version.

This program 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
this program. If not, see <http://www.gnu.org/licenses/>.
*/

#define ___lwasm_c_seen___

#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <ctype.h>

#include <lw_expr.h>
#include <lw_alloc.h>
#include <lw_string.h>

#include "lwasm.h"

void lwasm_register_error(asmstate_t *as, line_t *l, const char *msg, ...);

int lwasm_expr_exportable(asmstate_t *as, lw_expr_t expr)
{
	return 0;
}

int lwasm_expr_exportval(asmstate_t *as, lw_expr_t expr)
{
	return 0;
}

void lwasm_dividezero(void *priv)
{
	asmstate_t *as = (asmstate_t *)priv;
	lwasm_register_error(as, as -> cl, "Division by zero");
}

lw_expr_t lwasm_evaluate_var(char *var, void *priv)
{
	asmstate_t *as = (asmstate_t *)priv;
	lw_expr_t e;
	importlist_t *im;
	struct symtabe *s;
	
	s = lookup_symbol(as, as -> cl, var);
	if (s)
	{
		e = lw_expr_build(lw_expr_type_special, lwasm_expr_syment, s);
		return e;
	}
	
	if (as -> undefzero)
	{
		e = lw_expr_build(lw_expr_type_int, 0);
		return e;
	}
	
	// undefined here is undefied unless output is object
	if (as -> output_format != OUTPUT_OBJ)
		goto nomatch;
	
	// check for import
	for (im = as -> importlist; im; im = im -> next)
	{
		if (!strcmp(im -> symbol, var))
			break;
	}
	
	// check for "undefined" to import automatically
	if ((as -> passno != 0) && !im && CURPRAGMA(as -> cl, PRAGMA_UNDEFEXTERN))
	{
		im = lw_alloc(sizeof(importlist_t));
		im -> symbol = lw_strdup(var);
		im -> next = as -> importlist;
		as -> importlist = im;
	}
	
	if (!im)
		goto nomatch;

	e = lw_expr_build(lw_expr_type_special, lwasm_expr_import, im);
	return e;

nomatch:
	if (as -> badsymerr)
	{
		lwasm_register_error(as, as -> cl, "Undefined symbol %s", var);
	}
	return NULL;
}

lw_expr_t lwasm_evaluate_special(int t, void *ptr, void *priv)
{
	switch (t)
	{
	case lwasm_expr_secbase:
		{
//			sectiontab_t *s = priv;
			asmstate_t *as = priv;
			if (as -> exportcheck && ptr == as -> csect)
				return lw_expr_build(lw_expr_type_int, 0);
			if (((sectiontab_t *)ptr) -> flags & section_flag_constant)
				return lw_expr_build(lw_expr_type_int, 0);
			return NULL;
		}

	case lwasm_expr_linedlen:
		{
			line_t *cl = ptr;
			if (cl -> dlen == -1)
				return NULL;
			return lw_expr_build(lw_expr_type_int, cl -> dlen);
		}
		break;
					
	case lwasm_expr_linelen:
		{
			line_t *cl = ptr;
			if (cl -> len != -1)
				return lw_expr_build(lw_expr_type_int, cl -> len);
				
			if (cl -> as -> pretendmax)
			{
				if (cl -> maxlen != 0)
				{
					//fprintf(stderr, "Pretending max, len = %d\n", cl -> maxlen);
					return lw_expr_build(lw_expr_type_int, cl -> maxlen);
				}
			}
			return NULL;
		}
		break;
		
	case lwasm_expr_linedaddr:
		{
			line_t *cl = ptr;
			return lw_expr_copy(cl -> daddr);
		}
	
	case lwasm_expr_lineaddr:
		{
			line_t *cl = ptr;
			if (cl -> addr)
				return lw_expr_copy(cl -> addr);
			else
				return NULL;
		}
	
	case lwasm_expr_syment:
		{
			struct symtabe *sym = ptr;
			return lw_expr_copy(sym -> value);
		}
	
	case lwasm_expr_import:
		{
			return NULL;
		}
	
	case lwasm_expr_nextbp:
		{
			line_t *cl = ptr;
			for (cl = cl -> next; cl; cl = cl -> next)
			{
				if (cl -> isbrpt)
					break;
			}
			if (cl)
			{
				return lw_expr_copy(cl -> addr);
			}
			return NULL;
		}
	
	case lwasm_expr_prevbp:
		{
			line_t *cl = ptr;
			for (cl = cl -> prev; cl; cl = cl -> prev)
			{
				if (cl -> isbrpt)
					break;
			}
			if (cl)
			{
				return lw_expr_copy(cl -> addr);
			}
			return NULL;
		}
	}
	return NULL;
}

void lwasm_register_error_real(asmstate_t *as, line_t *l, char *iptr, const char *msg, va_list args)
{
	lwasm_error_t *e;
	char errbuff[1024];

	if (!l)
		return;

	e = lw_alloc(sizeof(lwasm_error_t));
	
	e -> next = l -> err;
	l -> err = e;
	e -> charpos = -1;
	
	if (iptr)
		e -> charpos = iptr - l -> ltext + 1;
	
	as -> errorcount++;
	
	(void)vsnprintf(errbuff, 1024, msg, args);
	e -> mess = lw_strdup(errbuff);
}

void lwasm_register_error(asmstate_t *as, line_t *l, const char *msg, ...)
{
	va_list args;
	
	va_start(args, msg);
	
	lwasm_register_error_real(as, l, NULL, msg, args);
	
	va_end(args);
}

void lwasm_register_error_n(asmstate_t *as, line_t *l, char *iptr, const char *msg, ...)
{
	va_list args;
	
	va_start(args, msg);
	
	lwasm_register_error_real(as, l, iptr, msg, args);
	
	va_end(args);
}

void lwasm_register_warning_real(asmstate_t *as, line_t *l, char *iptr, const char *msg, va_list args)
{
	lwasm_error_t *e;
	char errbuff[1024];
	
	if (!l)
		return;

	e = lw_alloc(sizeof(lwasm_error_t));
	
	e -> next = l -> warn;
	l -> warn = e;
	
	e -> charpos = -1;
	if (iptr)
		e -> charpos = iptr - l -> ltext + 1;
	
	as -> warningcount++;
	
	(void)vsnprintf(errbuff, 1024, msg, args);
	e -> mess = lw_strdup(errbuff);
}

void lwasm_register_warning(asmstate_t *as, line_t *l, const char *msg, ...)
{
	va_list args;
	
	va_start(args, msg);
	
	lwasm_register_warning_real(as, l, NULL, msg, args);
	
	va_end(args);
}

void lwasm_register_warning_n(asmstate_t *as, line_t *l, char *iptr, const char *msg, ...)
{
	va_list args;
	
	va_start(args, msg);
	
	lwasm_register_warning_real(as, l, iptr, msg, args);
	
	va_end(args);
}

int lwasm_next_context(asmstate_t *as)
{
	int r;
	r = as -> nextcontext;
	as -> nextcontext++;
	return r;
}

void lwasm_emit(line_t *cl, int byte)
{
	if (cl -> as -> output_format == OUTPUT_OBJ && cl -> csect == NULL)
	{
		lwasm_register_error(cl -> as, cl, "Instruction generating output outside of a section");
		return;
	}
	if (cl -> outputl < 0)
		cl -> outputl = 0;

	if (cl -> outputl == cl -> outputbl)
	{
		cl -> output = lw_realloc(cl -> output, cl -> outputbl + 8);
		cl -> outputbl += 8;
	}
	cl -> output[cl -> outputl++] = byte & 0xff;
	
	if (cl -> inmod)
	{
		asmstate_t *as = cl -> as;
		// update module CRC
		// this is a direct transliteration from the nitros9 asm source
		// to C; it can, no doubt, be optimized for 32 bit processing  
		byte &= 0xff;

		byte ^= (as -> crc)[0];
		(as -> crc)[0] = (as -> crc)[1];
		(as -> crc)[1] = (as -> crc)[2];
		(as -> crc)[1] ^= (byte >> 7);
		(as -> crc)[2] = (byte << 1); 
		(as -> crc)[1] ^= (byte >> 2);
		(as -> crc)[2] ^= (byte << 6);
		byte ^= (byte << 1);
		byte ^= (byte << 2);
		byte ^= (byte << 4);
		if (byte & 0x80) 
		{
			(as -> crc)[0] ^= 0x80;
		    (as -> crc)[2] ^= 0x21;
		}
	}
}

void lwasm_emitop(line_t *cl, int opc)
{
	if (opc > 0x100)
		lwasm_emit(cl, opc >> 8);
	lwasm_emit(cl, opc);
}

lw_expr_t lwasm_parse_term(char **p, void *priv)
{
	asmstate_t *as = priv;
	int neg = 1;
	int val;
	
	if (!**p)
		return NULL;
	
	if (**p == '.'
			&& !((*p)[1] >= 'A' && (*p)[1] <= 'Z')
			&& !((*p)[1] >= 'a' && (*p)[1] <= 'z')
			&& !((*p)[1] >= '0' && (*p)[1] <= '9')
		)
	{
		(*p)++;
		return lw_expr_build(lw_expr_type_special, lwasm_expr_linedaddr, as -> cl);
	}
	
	if (**p == '*')
	{
		// special "symbol" for current line addr (*)
		(*p)++;
		return lw_expr_build(lw_expr_type_special, lwasm_expr_lineaddr, as -> cl);
	}
	
	// branch points
	if (**p == '<')
	{
		(*p)++;
		return lw_expr_build(lw_expr_type_special, lwasm_expr_prevbp, as -> cl);
	}
	if (**p == '>')
	{
		(*p)++;
		return lw_expr_build(lw_expr_type_special, lwasm_expr_nextbp, as -> cl);
	}
	
	// double ascii constant
	if (**p == '"')
	{
		int v;
		(*p)++;
		if (!**p)
			return NULL;
		if (!*((*p)+1))
			return NULL;
		v = (unsigned char)**p << 8 | (unsigned char)*((*p)+1);
		(*p) += 2;
		return lw_expr_build(lw_expr_type_int, v);
	}
	
	if (**p == '\'')
	{
		int v;
		
		(*p)++;
		if (!**p)
			return NULL;
		
		v = (unsigned char)**p;
		(*p)++;
		return lw_expr_build(lw_expr_type_int, v);
	}
	
	if (**p == '&')
	{
		val = 0;
		// decimal constant
		(*p)++;
		
		if (**p == '-')
		{
			(*p)++;
			neg = -1;
		}

		if (!strchr("0123456789", **p))
			return NULL;

		while (**p && strchr("0123456789", **p))
		{
			val = val * 10 + (**p - '0');
			(*p)++;
		}
		return lw_expr_build(lw_expr_type_int, val * neg);
	}

	if (**p == '%')
	{
		val = 0;
		// binary constant
		(*p)++;

		if (**p == '-')
		{
			(*p)++;
			neg = -1;
		}

		if (**p != '0' && **p != '1')
			return NULL;

		while (**p && (**p == '0' || **p == '1'))
		{
			val = val * 2 + (**p - '0');
			(*p)++;
		}
		return lw_expr_build(lw_expr_type_int, val * neg);
	}
	
	if (**p == '$')
	{
		// hexadecimal constant
		int v = 0, v2;
		(*p)++;
		if (**p == '-')
		{
			(*p)++;
			neg = -1;
		}

		if (!strchr("0123456789abcdefABCDEF", **p))
			return NULL;

		while (**p && strchr("0123456789abcdefABCDEF", **p))
		{
			v2 = toupper(**p) - '0';
			if (v2 > 9)
				v2 -= 7;
			v = v * 16 + v2;
			(*p)++;
		}
		return lw_expr_build(lw_expr_type_int, v * neg);
	}
	
	if (**p == '0' && (*((*p)+1) == 'x' || *((*p)+1) == 'X'))
	{
		// hexadecimal constant, C style
		int v = 0, v2;
		(*p)+=2;

		if (!strchr("0123456789abcdefABCDEF", **p))
			return NULL;

		while (**p && strchr("0123456789abcdefABCDEF", **p))
		{
			v2 = toupper(**p) - '0';
			if (v2 > 9)
				v2 -= 7;
			v = v * 16 + v2;
			(*p)++;
		}
		return lw_expr_build(lw_expr_type_int, v);
	}
	
	if (**p == '@' && (*((*p)+1) >= '0' && *((*p)+1) <= '7'))
	{
		// octal constant
		int v = 0;
		(*p)++;
		if (**p == '-')
		{
			(*p)++;
			neg = -1;
		}


		if (!strchr("01234567", **p))
			return NULL;

		while (**p && strchr("01234567", **p))
		{
			v = v * 8 + (**p - '0');
			(*p)++;
		}
		return lw_expr_build(lw_expr_type_int, v * neg);
	}
	

	// symbol or bare decimal or suffix constant here
	do
	{
		int havedol = 0;
		int l = 0;
		
		while ((*p)[l] && strchr(SYMCHARS, (*p)[l]))
		{
			if ((*p)[l] == '$')
				havedol = 1;
			l++;
		}
		if (l == 0)
			return NULL;

		if ((*p)[l] == '{')
		{
			while ((*p)[l] && (*p)[l] != '}')
				l++;
			l++;
		}
		
		if (havedol || **p < '0' || **p > '9')
		{
			// have a symbol here
			char *sym;
			lw_expr_t term;
			
			sym = lw_strndup(*p, l);
			(*p) += l;
			term = lw_expr_build(lw_expr_type_var, sym);
			lw_free(sym);
			return term;
		}
	} while (0);
	
	if (!**p)
		return NULL;
	
	// we have a numeric constant here, either decimal or postfix base notation
	{
		int decval = 0, binval = 0, hexval = 0, octval = 0;
		int valtype = 15; // 1 = bin, 2 = oct, 4 = dec, 8 = hex
		int bindone = 0;
		int val;
		int dval;
		
		while (1)
		{
			if (!**p || !strchr("0123456789ABCDEFabcdefqhoQHO", **p))
			{
				// we can legally be bin or decimal here
				if (bindone)
				{
					// just finished a binary value
					val = binval;
					break;
				}
				else if (valtype & 4)
				{
					val = decval;
					break;
				}
				else
				{
					// bad value
					return NULL;
				}
			}
			
			dval = toupper(**p);
			(*p)++;
			
			if (bindone)
			{
				// any characters past "B" means it is not binary
				bindone = 0;
				valtype &= 14;
			}
			
			switch (dval)
			{
			case 'Q':
			case 'O':
				if (valtype & 2)
				{
					val = octval;
					valtype = -1;
					break;
				}
				else
				{
					return NULL;
				}
				/* can't get here */
			
			case 'H':
				if (valtype & 8)
				{
					val = hexval;
					valtype = -1;
					break;
				}
				else
				{
					return NULL;
				}
				/* can't get here */
			
			case 'B':
				// this is a bit of a sticky one since B may be a
				// hex number instead of the end of a binary number
				// so it falls through to the digit case
				if (valtype & 1)
				{
					// could still be binary of hex
					bindone = 1;
					valtype = 9;
				}
				/* fall through intented */
			
			default:
				// digit
				dval -= '0';
				if (dval > 9)
					dval -= 7;
				if (valtype & 8)
					hexval = hexval * 16 + dval;
				if (valtype & 4)
				{
					if (dval > 9)
						valtype &= 11;
					else
						decval = decval * 10 + dval;
				}
				if (valtype & 2)
				{
					if (dval > 7)
						valtype &= 13;
					else
						octval = octval * 8 + dval;
				}
				if (valtype & 1)
				{
					if (dval > 1)
						valtype &= 14;
					else
						binval = binval * 2 + dval;
				}
			}
			if (valtype == -1)
				break;
			
			// return if no more valid types
			if (valtype == 0)
				return NULL;
			
			val = decval; // in case we fall through	
		} 
		
		// get here if we have a value
		return lw_expr_build(lw_expr_type_int, val);
	}
	// can't get here
}

lw_expr_t lwasm_parse_expr(asmstate_t *as, char **p)
{
	lw_expr_t e;
	
	e = lw_expr_parse(p, as);
	
	return e;
}

int lwasm_reduce_expr(asmstate_t *as, lw_expr_t expr)
{
	if (expr)
		lw_expr_simplify(expr, as);
	return 0;
}

void lwasm_save_expr(line_t *cl, int id, lw_expr_t expr)
{
	struct line_expr_s *e;
	
	for (e = cl -> exprs; e; e = e -> next)
	{
		if (e -> id == id)
		{
			lw_expr_destroy(e -> expr);
			e -> expr = expr;
			return;
		}
	}
	
	e = lw_alloc(sizeof(struct line_expr_s));
	e -> expr = expr;
	e -> id = id;
	e -> next = cl -> exprs;
	cl -> exprs = e;
}

lw_expr_t lwasm_fetch_expr(line_t *cl, int id)
{
	struct line_expr_s *e;
	
	for (e = cl -> exprs; e; e = e -> next)
	{
		if (e -> id == id)
		{
			return e -> expr;
		}
	}
	return NULL;
}

void skip_operand(char **p)
{
	for (; **p && !isspace(**p); (*p)++)
		/* do nothing */ ;
}

int lwasm_emitexpr(line_t *l, lw_expr_t expr, int size)
{
	int v = 0;
	int ol;
	
	ol = l -> outputl;
	if (ol == -1)
		ol = 0;
		
	if (lw_expr_istype(expr, lw_expr_type_int))
	{
		v = lw_expr_intval(expr);
	}
	// handle external/cross-section/incomplete references here
	else
	{
		if (l -> as -> output_format == OUTPUT_OBJ)
		{
			reloctab_t *re;
			lw_expr_t te;

			if (l -> csect == NULL)
			{
				lwasm_register_error(l -> as, l, "Instruction generating output outside of a section");
				return -1;
			}
			
			if (size == 4)
			{
				// create a two part reference because lwlink doesn't
				// support 32 bit references
				lw_expr_t te2;
				te = lw_expr_build(lw_expr_type_int, 0x10000);
				te2 = lw_expr_build(lw_expr_type_oper, lw_expr_oper_divide, expr, te);
				lw_expr_destroy(te);
				
				re = lw_alloc(sizeof(reloctab_t));
				re -> next = l -> csect -> reloctab;
				l -> csect -> reloctab = re;
				te = lw_expr_build(lw_expr_type_int, ol);
				re -> offset = lw_expr_build(lw_expr_type_oper, lw_expr_oper_plus, l -> addr, te);
				lw_expr_destroy(te);
				lwasm_reduce_expr(l -> as, re -> offset);
				re -> expr = te2;
				re -> size = 2;

				te = lw_expr_build(lw_expr_type_int, 0xFFFF);
				te2 = lw_expr_build(lw_expr_type_oper, lw_expr_oper_bwand, expr, te);
				lw_expr_destroy(te);
				
				re = lw_alloc(sizeof(reloctab_t));
				re -> next = l -> csect -> reloctab;
				l -> csect -> reloctab = re;
				te = lw_expr_build(lw_expr_type_int, ol + 2);
				re -> offset = lw_expr_build(lw_expr_type_oper, lw_expr_oper_plus, l -> addr, te);
				lw_expr_destroy(te);
				lwasm_reduce_expr(l -> as, re -> offset);
				re -> expr = te2;
				re -> size = 2;
			}
			else
			{
				// add "expression" record to section table
				re = lw_alloc(sizeof(reloctab_t));
				re -> next = l -> csect -> reloctab;
				l -> csect -> reloctab = re;
				te = lw_expr_build(lw_expr_type_int, ol);
				re -> offset = lw_expr_build(lw_expr_type_oper, lw_expr_oper_plus, l -> addr, te);
				lw_expr_destroy(te);
				lwasm_reduce_expr(l -> as, re -> offset);
				re -> size = size;
				re -> expr = lw_expr_copy(expr);
			}
			for (v = 0; v < size; v++)
				lwasm_emit(l, 0);
			return 0;
		}
		lwasm_register_error(l -> as, l, "Expression not fully resolved");
		return -1;
	}
	
	switch (size)
	{
	case 4:
		lwasm_emit(l, v >> 24);
		lwasm_emit(l, v >> 16);
		/* fallthrough intended */
			
	case 2:
		lwasm_emit(l, v >> 8);
		/* fallthrough intended */
		
	case 1:
		lwasm_emit(l, v);
	}
	
	return 0;
}

int lwasm_lookupreg2(const char *regs, char **p)
{
	int rval = 0;
	
	while (*regs)
	{
		if (toupper(**p) == *regs)
		{
			if (regs[1] == ' ' && !isalpha(*(*p + 1)))
				break;
			if (toupper(*(*p + 1)) == regs[1])
				break;
		}
		regs += 2;
		rval++;
	}
	if (!*regs)
		return -1;
	if (regs[1] == ' ')
		(*p)++;
	else
		(*p) += 2;
	return rval;
}

int lwasm_lookupreg3(const char *regs, char **p)
{
	int rval = 0;
	
	while (*regs)
	{
		if (toupper(**p) == *regs)
		{
			if (regs[1] == ' ' && !isalpha(*(*p + 1)))
				break;
			if (toupper(*(*p + 1)) == regs[1])
			{
				if (regs[2] == ' ' && !isalpha(*(*p + 2)))
					break;
				if (toupper(*(*p + 2)) == regs[2])
					break;
			}
		}
		regs += 3;
		rval++;
	}
	if (!*regs)
		return -1;
	if (regs[1] == ' ')
		(*p)++;
	else if (regs[2] == ' ')
		(*p) += 2;
	else
		(*p) += 3;
	return rval;
}

void lwasm_show_errors(asmstate_t *as)
{
	line_t *cl;
	lwasm_error_t *e;
	
	for (cl = as -> line_head; cl; cl = cl -> next)
	{
		if (!(cl -> err) && !(cl -> warn))
			continue;
		for (e = cl -> err; e; e = e -> next)
		{
			fprintf(stderr, "ERROR: %s\n", e -> mess);
		}
		for (e = cl -> warn; e; e = e -> next)
		{
			fprintf(stderr, "WARNING: %s\n", e -> mess);
		}
		fprintf(stderr, "%s:%05d %s\n\n", cl -> linespec, cl -> lineno, cl -> ltext);
	}
}

/*
this does any passes and other gymnastics that might be useful
to see if an expression reduces early
*/
extern void do_pass3(asmstate_t *as);
extern void do_pass4_aux(asmstate_t *as, int force);

void lwasm_interim_reduce(asmstate_t *as)
{
	do_pass3(as);
//	do_pass4_aux(as, 0);
}

lw_expr_t lwasm_parse_cond(asmstate_t *as, char **p)
{
	lw_expr_t e;

	debug_message(as, 250, "Parsing condition");
	e = lwasm_parse_expr(as, p);
	debug_message(as, 250, "COND EXPR: %s", lw_expr_print(e));
	
	if (!e)
	{
		lwasm_register_error(as, as -> cl, "Bad expression");
		return NULL;
	}

	/* handle condundefzero */
	if (CURPRAGMA(as -> cl, PRAGMA_CONDUNDEFZERO))
	{
		as -> undefzero = 1;
		lwasm_reduce_expr(as, e);
		as -> undefzero = 0;
	}

	/* we need to simplify the expression here */
	debug_message(as, 250, "Doing interim reductions");
	lwasm_interim_reduce(as);
	debug_message(as, 250, "COND EXPR: %s", lw_expr_print(e));
	debug_message(as, 250, "Reducing expression");
	lwasm_reduce_expr(as, e);
	debug_message(as, 250, "COND EXPR: %s", lw_expr_print(e));
/*	lwasm_reduce_expr(as, e);
	debug_message(as, 250, "COND EXPR: %s", lw_expr_print(e));
	lwasm_reduce_expr(as, e);
	debug_message(as, 250, "COND EXPR: %s", lw_expr_print(e));
	lwasm_reduce_expr(as, e);
	debug_message(as, 250, "COND EXPR: %s", lw_expr_print(e));
*/

	lwasm_save_expr(as -> cl, 4242, e);

	if (!lw_expr_istype(e, lw_expr_type_int))
	{
		debug_message(as, 250, "Non-constant expression");
		lwasm_register_error(as, as -> cl, "Conditions must be constant on pass 1");
		return NULL;
	}
	debug_message(as, 250, "Returning expression");
	return e;
}

struct range_data
{
	int min;
	int max;
	asmstate_t *as;
};
int lwasm_calculate_range(asmstate_t *as, lw_expr_t expr, int *min, int *max);
int lwasm_calculate_range_tf(lw_expr_t e, void *info)
{
	struct range_data *rd = info;
	int i;
	
	if (lw_expr_istype(e, lw_expr_type_int))
	{
		i = lw_expr_intval(e);
		rd -> min += i;
		rd -> max += i;
		return 0;
	}
	
	if (lw_expr_istype(e, lw_expr_type_special))
	{
		line_t *l;
		if (lw_expr_specint(e) != lwasm_expr_linelen)
		{
			rd -> min = -1;
			return -1;
		}
		l = (line_t *)lw_expr_specptr(e);
		if (l -> len == -1)
		{
			rd -> min += l -> minlen;
			rd -> max += l -> maxlen;
		}
		else
		{
			rd -> min += l -> len;
		}
		return 0;
	}
	
	if (lw_expr_istype(e, lw_expr_type_var))
	{
		lw_expr_t te;
		te = lw_expr_copy(e);
		lwasm_reduce_expr(rd -> as, te);
		if (lw_expr_istype(te, lw_expr_type_int))
		{
			i = lw_expr_intval(te);
			rd -> min += i;
			rd -> max += i;
		}
		else
		{
			rd -> min = -1;
		}
		lw_expr_destroy(te);
		if (rd -> min == -1)
			return -1;
		return 0;
	}
	
	if (lw_expr_istype(e, lw_expr_type_oper))
	{
		if (lw_expr_whichop(e) == lw_expr_oper_plus)
			return 0;
		rd -> min = -1;
		return -1;
	}
	
	rd -> min = -1;
	return -1;
}

int lwasm_calculate_range(asmstate_t *as, lw_expr_t expr, int *min, int *max)
{
	struct range_data rd;
	
	rd.min = 0;
	rd.max = 0;
	rd.as = as;
	
	if (!expr)
		return -1;
	
	lw_expr_testterms(expr, lwasm_calculate_range_tf, (void *)&rd);
	*min = rd.min;
	*max = rd.max;
	if (rd.min == -1)
		return -1;
	return 0;
}