view lwasm/lwasm.c @ 374:8e25147c2aa8

Clean up various "externs" Apparently some compilers seriously choke on the "extern" keyword in some circumstances where GCC does not. Remove most instances of "extern" to guard against that. Thanks to Erik G <erik@6809.org> for the patch.
author William Astle <lost@l-w.ca>
date Mon, 13 Jul 2015 20:31:56 -0600
parents 8764142b3192
children 71f507f404f1
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/>.
*/

#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"
#include "instab.h"

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, E_DIV0);
}

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_error2(as, as -> cl, E_SYMBOL_UNDEFINED, "%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;
}

const char* lwasm_lookup_error(lwasm_errorcode_t error_code)
{
	switch (error_code)
	{
		case E_6309_INVALID:			return "Illegal use of 6309 instruction in 6809 mode";
		case E_6809_INVALID:			return "Illegal use of 6809 instruction in 6309 mode";
		case E_ALIGNMENT_INVALID:		return "Invalid alignment";
		case E_BITNUMBER_INVALID:		return "Invalid bit number";
		case E_BITNUMBER_UNRESOLVED:	return "Bit number must be fully resolved";
		case E_BYTE_OVERFLOW:			return "Byte overflow";
		case E_CONDITION_P1:			return "Conditions must be constant on pass 1";
		case E_DIRECTIVE_OS9_ONLY:		return "Directive only valid for OS9 target";
		case E_DIV0:					return "Division by zero";
		case E_EXEC_ADDRESS:			return "Exec address not constant!";
		case E_EXPRESSION_BAD:			return "Bad expression";
		case E_EXPRESSION_NOT_CONST:	return "Expression must be constant";
		case E_EXPRESSION_NOT_RESOLVED: return "Expression not fully resolved";
		case E_FILE_OPEN:				return "Cannot open file";
		case E_FILENAME_MISSING:		return "Missing filename";
		case E_FILL_INVALID:			return "Invalid fill length";
		case E_IMMEDIATE_INVALID:		return "Immediate mode not allowed";
		case E_IMMEDIATE_UNRESOLVED:	return "Immediate byte must be fully resolved";
		case E_INSTRUCTION_FAILED:		return "Instruction failed to resolve.";
		case E_INSTRUCTION_SECTION:		return "Instruction generating output outside of a section";
		case E_LINE_ADDRESS:			return "Cannot resolve line address";
		case E_LINED_ADDRESS:			return "Cannot resolve line data address";
		case E_OBJTARGET_ONLY:			return "Only supported for object target";
		case E_OPCODE_BAD:				return "Bad opcode";
		case E_OPERAND_BAD:				return "Bad operand";
		case E_PADDING_BAD:				return "Bad padding";
		case E_PRAGMA_UNRECOGNIZED:		return "Unrecognized pragma string";
		case E_REGISTER_BAD:			return "Bad register";
		case E_SETDP_INVALID:			return "SETDP not permitted for object target";
		case E_SETDP_NOT_CONST:			return "SETDP must be constant on pass 1";
		case E_STRING_BAD:				return "Bad string condition";
		case E_SYMBOL_BAD:				return "Bad symbol";
		case E_SYMBOL_MISSING:			return "Missing symbol";
		case E_SYMBOL_UNDEFINED_EXPORT: return "Undefined exported symbol";
		case E_MACRO_DUPE:				return "Duplicate macro definition";
		case E_MACRO_ENDM:				return "ENDM without MACRO";
		case E_MACRO_NONAME:			return "Missing macro name";
		case E_MACRO_RECURSE:			return "Attempt to define a macro inside a macro";
		case E_MODULE_IN:				return "Already in a module!";
		case E_MODULE_NOTIN:			return "Not in a module!";
		case E_NEGATIVE_BLOCKSIZE:		return "Negative block sizes make no sense!";
		case E_NEGATIVE_RESERVATION:	return "Negative reservation sizes make no sense!";
		case E_NW_8:					return "n,W cannot be 8 bit";
		case E_SECTION_END:				return "ENDSECTION without SECTION";
		case E_SECTION_EXTDEP:			return "EXTDEP must be within a section";
		case E_SECTION_FLAG:			return "Unrecognized section flag";
		case E_SECTION_NAME:			return "Need section name";
		case E_SECTION_TARGET:			return "Cannot use sections unless using the object target";
		case E_STRUCT_DUPE:				return "Duplicate structure definition";
		case E_STRUCT_NONAME:			return "Cannot declare a structure without a symbol name.";
		case E_STRUCT_NOSYMBOL:			return "Structure definition with no effect - no symbol";
		case E_STRUCT_RECURSE:			return "Attempt to define a structure inside a structure";
		case E_SYMBOL_DUPE:				return "Multiply defined symbol";
		case E_UNKNOWN_OPERATION:		return "Unknown operation";

		case W_ENDSTRUCT_WITHOUT:		return "ENDSTRUCT without STRUCT";
		case W_DUPLICATE_SECTION:		return "Section flags can only be specified the first time; ignoring duplicate definition";
		case W_NOT_SUPPORTED:			return "Not supported";

		default:						return "Error";
	}
}

void lwasm_register_error_real(asmstate_t *as, line_t *l, lwasm_errorcode_t err, const char *msg)
{
	lwasm_error_t *e;

	if (!l)
		return;

	e = lw_alloc(sizeof(lwasm_error_t));

	if (err >= 1000)
	{
		e->next = l->warn;
		l->warn = e;
		as->warningcount++;
	}
	else
	{
		e->next = l->err;
		l->err = e;
		as->errorcount++;
	}
	
	e -> charpos = -1;

	e -> mess = lw_strdup(msg);
}

void lwasm_register_error(asmstate_t *as, line_t *l, lwasm_errorcode_t err)
{
	lwasm_register_error_real(as, l, err, lwasm_lookup_error(err));
}

void lwasm_register_error2(asmstate_t *as, line_t *l, lwasm_errorcode_t err, const char* fmt, ...)
{
	char errbuff[1024];
	char f[128];

	sprintf(f, "%s %s", lwasm_lookup_error(err), fmt);

	va_list args;

	va_start(args, fmt);

	(void) vsnprintf(errbuff, 1024, f, args);

	lwasm_register_error_real(as, l, err, errbuff);

	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, E_INSTRUCTION_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;
		
		if (**p == '"')
			(*p)++;
		
		return lw_expr_build(lw_expr_type_int, v);
	}
	
	if (**p == '\'')
	{
		int v;
		
		(*p)++;
		if (!**p)
			return NULL;
		
		v = (unsigned char)**p;
		(*p)++;
		
		if (**p == '\'')
			(*p)++;
		
		return lw_expr_build(lw_expr_type_int, v);
	}
	
	if (**p == '&')
	{
		val = 0;
		// decimal constant
		(*p)++;
		
		if (**p == '-')
		{
			(*p)++;
			neg = -1;
		}

		if (!**p || !strchr("0123456789", **p))
		{
			(*p)--;
			if (neg < 0)
				(*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')
		{
			(*p)--;
			if (neg < 0)
				(*p)--;
			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 (!**p || !strchr("0123456789abcdefABCDEF", **p))
		{
			(*p)--;
			if (neg < 0)
				(*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 (!**p || !strchr("0123456789abcdefABCDEF", **p))
		{
			(*p) -= 2;
			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 (!**p || !strchr("01234567", **p))
		{
			(*p)--;
			if (neg < 0)
				(*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;

	if (as->exprwidth != 16)	
	{
		lw_expr_setwidth(as->exprwidth);
		e = lw_expr_parse(p, as);
		lw_expr_setwidth(0);
	}
	else
	{
		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, E_INSTRUCTION_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, E_EXPRESSION_NOT_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
*/
void do_pass3(asmstate_t *as);
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, E_EXPRESSION_BAD);
		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, E_CONDITION_P1);
		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;
}

void lwasm_reduce_line_exprs(line_t *cl)
{
	asmstate_t *as;
	struct line_expr_s *le;
	int i;
			
	as = cl -> as;
	as -> cl = cl;
			
	// simplify address
	lwasm_reduce_expr(as, cl -> addr);
		
	// simplify data address
	lwasm_reduce_expr(as, cl -> daddr);

	// simplify each expression
	for (i = 0, le = cl -> exprs; le; le = le -> next, i++)
	{
		lwasm_reduce_expr(as, le -> expr);
		debug_message(as, 100, "Reduce expressions: exp[%d] = %s", i, lw_expr_print(le -> expr));
	}
			
	if (cl -> len == -1 || cl -> dlen == -1)
	{
		// try resolving the instruction length
		// but don't force resolution
		if (cl -> insn >= 0 && instab[cl -> insn].resolve)
		{
			(instab[cl -> insn].resolve)(as, cl, 0);
			if ((cl -> inmod == 0) && cl -> len >= 0 && cl -> dlen >= 0)
			{
				if (cl -> len == 0)
					cl -> len = cl -> dlen;
				else
					cl -> dlen = cl -> len;
			}
		}
	}
	debug_message(as, 100, "Reduce expressions: len = %d", cl -> len);
	debug_message(as, 100, "Reduce expressions: dlen = %d", cl -> dlen);
	debug_message(as, 100, "Reduce expressions: addr = %s", lw_expr_print(cl -> addr));
	debug_message(as, 100, "Reduce expressions: daddr = %s", lw_expr_print(cl -> daddr));
}