--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lwasm/lwasm.c	Fri Jan 30 04:01:55 2009 +0000
@@ -0,0 +1,428 @@
+/*
+lwasm.c
+Copyright © 2009 William Astle
+
+This file is part of LWASM.
+
+LWASM 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/>.
+
+
+Contains random functions used by the assembler
+*/
+
+#define __lwasm_c_seen__
+
+#include <stdarg.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "lwasm.h"
+#include "util.h"
+#include "expr.h"
+
+int debug_level = 0;
+
+int register_error(asmstate_t *as, lwasm_line_t *l, int pass, const char *fmt, ...)
+{
+	lwasm_error_t *e;
+	va_list args;
+	char errbuff[1024];
+	int r;
+	
+	if (!l)
+		return;
+
+	if (as -> passnum != pass)
+		return;
+	
+	va_start(args, fmt);
+	
+	e = lwasm_alloc(sizeof(lwasm_error_t));
+	
+	e -> next = l -> err;
+	l -> err = e;
+	
+	as -> errorcount++;
+	
+	r = vsnprintf(errbuff, 1024, fmt, args);
+	e -> mess = lwasm_strdup(errbuff);
+	
+	va_end(args);
+	
+	return r;
+}
+
+void lwasm_emit(asmstate_t *as, lwasm_line_t *l, int b)
+{
+	as -> addr += 1;
+	as -> addr &= 0xffff;
+	
+	if (as -> outformat == OUTPUT_OBJ && !(as -> csect))
+	{
+		register_error(as, l, 1, "Output not allowed outside sections with obj target");
+		return;
+	}
+	if (as -> outformat == OUTPUT_OBJ && as -> csect -> flags & SECTION_BSS)
+	{
+		register_error(as, l, 1, "Output not allowed inside BSS sections");
+		return;
+	}
+	if (as -> passnum == 1)
+		return;
+
+
+	if (l -> codelen >= l -> codesize)
+	{
+		l -> bytes = realloc(l -> bytes, l -> codesize + 16);
+		l -> codesize += 16;
+	}
+	l -> bytes[l -> codelen] = b & 0xff;
+	l -> codelen += 1;
+}
+
+void lwasm_emitop(asmstate_t *as, lwasm_line_t *l, int o)
+{
+	if (o >= 0x100)
+		lwasm_emit(as, l, o >> 8);
+	lwasm_emit(as, l, o & 0xff);
+}
+
+int lwasm_lookupreg2(const char *reglist, char **str)
+{
+	int rval = 0;
+
+	while (*reglist)
+	{
+		if (toupper(**str) == *reglist)
+		{
+			// first char matches
+			if (reglist[1] == ' ' && !isalpha(*(*str + 1)))
+				break;
+			if (toupper(*(*str + 1)) == reglist[1])
+				break;
+		}
+		reglist += 2;
+		rval++;
+	}
+	if (!*reglist)
+		return -1;
+	if (reglist[1] == ' ')
+		(*str)++;
+	else
+		(*str) += 2;
+	return rval;
+}
+
+int lwasm_lookupreg3(const char *rlist, const char **str)
+{
+	int rval = 0;
+	int f = 0;
+	const char *reglist = rlist;
+		
+	while (*reglist)
+	{
+		if (toupper(**str) == *reglist)
+		{
+			// first char matches
+			if (reglist[1] == ' ')
+			{
+				f = 1;
+				break;
+			}
+			if (toupper(*(*str + 1)) == reglist[1])
+			{
+				// second char matches
+				if (reglist[2] == ' ')
+				{
+					f = 1;
+					break;
+				}
+				if (toupper(*(*str + 2)) == reglist[2])
+				{
+					f = 1;
+					break;
+				}
+			}
+		}
+		reglist += 3;
+		rval++;
+	}
+	if (f == 0)
+		return -1;
+	
+	
+	reglist = rval * 3 + rlist;
+	if (reglist[1] == ' ')
+		(*str) += 1;
+	else if (reglist[2] == ' ')
+		(*str) += 2;
+	else
+		(*str)+=3;
+	return rval;
+}
+
+struct symstateinfo
+{
+	asmstate_t *as;
+	lwasm_line_t *l;
+	int flags;
+};	
+
+lwasm_expr_stack_t *lwasm_expr_lookup_symbol(char *sym, void *state)
+{
+	lwasm_symbol_ent_t *se;
+	struct symstateinfo *st;
+	lwasm_expr_stack_t *rs;
+	lwasm_expr_term_t *t;
+	lwasm_expr_stack_node_t *n;
+	
+	int val;
+	
+	st = state;
+	debug_message(3, "lwasm_expr_lookup_symbol(): find '%s' (context=%d)", sym, st -> as -> context);	
+
+	// check for special symbols first...
+	if (sym[1] == '\0')
+	{
+		switch (sym[0])
+		{
+		// current line address
+		case '*':
+		case '.':
+			val = st -> l -> codeaddr;
+			goto retconst;
+		
+		case '<':
+			// previous branch point
+			// not implemented
+			break;
+		case '>':
+			// next branch point
+			// not implemented
+			break;
+		}
+	}
+
+	// look for local symbol first then global symbol
+	se = lwasm_find_symbol(st -> as, sym, st -> as -> context);
+	if (!se)
+		se = lwasm_find_symbol(st -> as, sym, -1);
+	debug_message(3, "lwasm_expr_lookup_symbol(): got '%p'", se);
+	if (!se)
+	{
+		register_error(st -> as, st -> l, 2, "Undefined symbol '%s'", sym);
+		return NULL;
+	}
+	// external reference - can not resolve it
+	if (se -> flags & SYMBOL_EXTERN)
+	{
+		return NULL;
+	}
+	if (st -> flags & EXPR_SECTCONST)
+	{
+		if (se -> sect == st -> l -> sect)
+		{
+			if (se -> expr)
+				goto retsym;
+			val = se -> value;
+			goto retconst;
+		}
+	}
+	if (st -> as -> outformat == OUTPUT_OBJ && se -> sect != NULL)
+	{
+		return NULL;
+	}
+	if (st -> as -> outformat != OUTPUT_OBJ || se -> sect == NULL)
+	{
+		// global symbol, intrasegment reference, or not an object target
+		val = se -> value;
+		goto retconst;
+	}
+	
+	// an intersegment reference will return as NULL (to be resolved at output/link time)
+	// if se -> expr is NULL, it has to be an intersegment reference here
+	if (se -> expr == NULL)
+	{
+		return NULL;
+	}
+	
+retsym:
+	// duplicate the expression for return
+	rs = lwasm_expr_stack_create();
+	for (n = se -> expr -> head; n; n = n -> next)
+	{
+		lwasm_expr_stack_push(rs, n -> term);
+	}
+	return rs;
+
+retconst:
+	rs = lwasm_expr_stack_create();
+	t = lwasm_expr_term_create_int(val);
+	lwasm_expr_stack_push(rs, t);
+	lwasm_expr_term_free(t);
+	return rs;
+}
+
+lwasm_expr_stack_t *lwasm_evaluate_expr(asmstate_t *as, lwasm_line_t *l, const char *inp, const char **outp, int flags)
+{
+	struct symstateinfo st;
+	
+	st.as = as;
+	st.l = l;
+	st.flags = flags;
+	
+	debug_message(2, "Evaluate expression: %s", inp);
+	
+	return(lwasm_expr_eval(inp, outp, lwasm_expr_lookup_symbol, &st));
+}
+
+
+int lwasm_reevaluate_expr(asmstate_t *as, lwasm_line_t *l, lwasm_expr_stack_t *s, int flags)
+{
+	struct symstateinfo st;
+	
+	st.as = as;
+	st.l = l;
+	st.flags = flags;
+	return(lwasm_expr_reval(s, lwasm_expr_lookup_symbol, &st));
+}
+
+// return 1 if no undefined symbols (externals and incompletes are okay)
+// return 0 if there are undefined symbols
+int lwasm_expr_result_ckconst(asmstate_t *as, lwasm_expr_stack_t *s)
+{
+	lwasm_expr_stack_node_t *n;
+	lwasm_symbol_ent_t *se;
+	
+	if (as -> outformat != OUTPUT_OBJ)
+	{
+		if (lwasm_expr_is_constant(s))
+			return 1;
+		else
+			return 0;
+	}
+	
+	for (n = s -> head; n; n = n -> next)
+	{
+		if (n -> term -> term_type == LWASM_TERM_SYM)
+		{
+			se = lwasm_find_symbol(as, n -> term -> symbol, as -> context);
+			if (!se)
+				se = lwasm_find_symbol(as, n -> term -> symbol, -1);
+			if (!se)
+				return 0;
+		}
+	}
+	return 1;
+}
+
+/*
+Evaluate an expression according to the flag value. Return 0 if a constant result was
+obtained, 1 if an incomplete result was obtained, and -1 if an error was flagged.
+
+*/
+int lwasm_expr_result2(asmstate_t *as, lwasm_line_t *l, char **inp, int flag, int *val, int slot)
+{
+	lwasm_expr_stack_t *s = NULL;
+	const char *ep;
+	int rval;
+
+	if ((as -> passnum == 1 && !(flag & EXPR_REEVAL)) || slot < 0)
+	{		
+		s = lwasm_evaluate_expr(as, l, *inp, &ep, flag);
+		if (slot >= 0)
+			l -> exprs[slot] = s;
+		if (!s)
+		{
+			register_error(as, l, 1, "Bad expression");
+			*val = 0;
+			return -1;
+		}
+		*inp = (char *)ep;
+		if (slot >= 0)
+		{
+			l -> exprends[slot] = (char *)ep;
+			l -> exprvals[slot] = lwasm_expr_get_value(s);
+		}
+	}
+	else if (l -> exprs[slot])
+	{
+		s = l -> exprs[slot];
+		lwasm_reevaluate_expr(as, l, s, flag);
+		l -> exprvals[slot] = lwasm_expr_get_value(s);
+	}
+	if (as -> passnum == 2 && slot >= 0)
+		*inp = l -> exprends[slot];
+
+	if (s && lwasm_expr_is_constant(s))
+	{
+		*val = lwasm_expr_get_value(s);
+		lwasm_expr_stack_free(s);
+		l -> exprs[slot] = NULL;
+		s = NULL;
+		return 0;
+	}
+
+	if (!s && slot >= 0)
+	{
+		*val = l -> exprvals[slot];
+		return 0;
+	}
+	else if (!s)
+	{
+		*val = 0;
+		return 0;
+	}
+
+	// was a constant result on pass 1 requested?
+	// that means we must have a constant on either pass
+	if (flag & EXPR_PASS1CONST)
+	{
+		*val = 0;
+		if (slot >= 0)
+			l -> exprvals[slot] = 0;
+		register_error(as, l, 1, "Illegal forward, external, or inter-section reference");
+		lwasm_expr_stack_free(s);
+		if (slot >= 0)
+			l -> exprs[slot] = NULL;
+		return -1;
+	}
+	
+	return 1;
+}
+
+void debug_message(int level, const char *fmt, ...)
+{
+	va_list args;
+	
+	va_start(args, fmt);
+	if (debug_level >= level)
+	{
+		if (level > 0)
+			fprintf(stderr, "DEBUG %d: ", level);
+		vfprintf(stderr, fmt, args);
+		fputc('\n', stderr);
+	}
+	va_end(args);
+}
+
+int lwasm_next_context(asmstate_t *as)
+{
+	int r;
+	r = as -> nextcontext;
+	as -> nextcontext += 1;
+	debug_message(3, "lwasm_next_context(): %d (%d) pass %d", r, as -> nextcontext, as -> passnum);
+	return r;
+}
+