/*
pseudo.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/>.


This file implements the various pseudo operations.
*/

#include <stdlib.h>
#include <string.h>
#include "lwasm.h"
#include "instab.h"
#include "expr.h"
#include "util.h"

extern int lwasm_read_file(asmstate_t *as, const char *filename);

OPFUNC(pseudo_org)
{
	int v, r;

	if (as -> csect)
	{
		register_error(as, l, 1, "ORG not allowed within sections");
		return;
	}

	if (as -> passnum != 1)
	{
		// org is not needed to be processed on pass 2
		// this will prevent phasing errors for forward references that
		// resolve on the second pass
		// we saved the org address in l -> codeaddr on pass 1
		as -> addr = l -> codeaddr;
		return;
	}
	
	if (l -> sym)
	{
		register_error(as, l, 1, "No symbol allowed with ORG");
	}
	
	r = lwasm_expr_result2(as, l, p, EXPR_PASS1CONST, &v, 0);
	if (r != 0)
		return;
	l -> codeaddr = v;
	l -> addrset = 1;
	as -> addr = v;
}

/*
The operand for include is a string optionally enclosed in "
*/
OPFUNC(pseudo_include)
{
	int v1;
	char *fn;
	
	// only include files on pass 1
	// but make sure local include context is right
	// for the next line...
	if (as -> passnum != 1)
	{
		as -> context = lwasm_next_context(as);
		return;
	}

	while (**p && isspace(**p))
		(*p)++;

	if (!**p)
	{
		register_error(as, l, 1, "Bad file name");
		return;
	}

	if (**p == '"')
	{
		// search for ending "
		(*p)++;
		for (v1 = 0; *((*p)+v1) && *((*p)+v1) != '"'; v1++)
			/* do nothing */ ;
		if (*((*p)+v1) != '"')
		{
			register_error(as, l, 1, "Bad file name");
			return;
		}
	}
	else
	{
		// search for a space type character
		for (v1 = 0; *((*p)+v1) && !isspace(*((*p)+v1)); v1++)
			;
	}

	fn = lwasm_alloc(v1 + 1);
	memcpy(fn, *p, v1);
	fn[v1] = '\0';

	// end local label context on include	
	as -> context = lwasm_next_context(as);
	if (lwasm_read_file(as, fn) < 0)
	{
		register_error(as, l, 1, "File include error (%s)", fn);
	}
	lwasm_free(fn);
}

OPFUNC(pseudo_rmb)
{
	int r, v;
	
	if (as -> passnum == 1)
	{
		as -> addr += l -> nocodelen;
		return;
	}
	
	r = lwasm_expr_result2(as, l, p, EXPR_PASS1CONST, &v, 0);
	if (r != 0)
		return;
	l -> nocodelen = v;
	as -> addr += v;
}

OPFUNC(pseudo_rmd)
{
	int r, v;
	
	if (as -> passnum == 1)
	{
		as -> addr += l -> nocodelen;
		return;
	}
	r = lwasm_expr_result2(as, l, p, EXPR_PASS1CONST, &v, 0);
	if (r != 0)
		return;
	v *= 2;
	l -> nocodelen = v;
	as -> addr += v;
}

OPFUNC(pseudo_rmq)
{
	int r, v;
	
	if (as -> passnum == 1)
	{
		as -> addr += l -> nocodelen;
		return;
	}
	r = lwasm_expr_result2(as, l, p, EXPR_PASS1CONST, &v, 0);
	if (r != 0)
		return;
	v *= 4;
	l -> nocodelen = v;
	as -> addr += v;
}

OPFUNC(pseudo_zmb)
{
	int r, v;
	
	r = lwasm_expr_result2(as, l, p, EXPR_PASS1CONST, &v, 0);
	if (r != 0)
		return;
	while (v--)
		lwasm_emit(as, l, 0);
}

OPFUNC(pseudo_zmd)
{
	int r, v;
	
	r = lwasm_expr_result2(as, l, p, EXPR_PASS1CONST, &v, 0);
	if (r != 0)
		return;
	v *= 2;
	while (v--)
		lwasm_emit(as, l, 0);
}

OPFUNC(pseudo_zmq)
{
	int r, v;
	
	r = lwasm_expr_result2(as, l, p, EXPR_PASS1CONST, &v, 0);
	if (r != 0)
		return;
	v *= 4;
	while (v--)
		lwasm_emit(as, l, 0);
}

OPFUNC(pseudo_end)
{
	int r, v;
	lwasm_expr_stack_t *s;
	

	as -> endseen = 1;
	
	// address only matters for DECB output
	if (as -> outformat != OUTPUT_DECB)
		return;
	
	r = lwasm_expr_result2(as, l, p, 0, &v, 0);
	if (r != 0)
	{
		register_error(as, l, 2, "Bad operand");
	}

	v = v & 0xffff;
	if (as -> passnum == 2)
	{
		as -> execaddr = v;
		l -> symaddr = v;
		l -> addrset = 2;
	}
}


OPFUNC(pseudo_align)
{
	int cn;
	int r, v;
	
	if (as -> passnum == 2)
	{
		while (as -> addr < l -> symaddr)
			lwasm_emit(as, l, 0);
		return;
	}
	
	r = lwasm_expr_result2(as, l, p, EXPR_PASS1CONST, &v, 0);
	if (r != 0)
	{
		l -> symaddr = as -> addr;
		return;
	}

	if (v < 1)
	{
		register_error(as, l, 1, "Illegal alignment %d", v);
		return;
	}
	
	cn = l -> codeaddr % v;
	if (cn)
		cn = v - cn; 

	while (cn--)
	{
		lwasm_emit(as, l, 0);
	}
	l -> symaddr = as -> addr;
}

OPFUNC(pseudo_equ)
{
	int r, v;

	if (l -> sym == NULL)
	{
		register_error(as, l, 1, "No symbol specified");
		return;
	}

	r = lwasm_expr_result2(as, l, p, EXPR_PASS1CONST, &v, 0);
	if (r < 0)
		v = 0;

	l -> symaddr = v & 0xFFFF;
	l -> addrset = 2;
	
	// note: we need to do this because the symbol might have resolved
	// to a constant!
	lwasm_register_symbol(as, l, l -> sym, v, (r > 0 ? SYMBOL_COMPLEX: SYMBOL_NORM) | SYMBOL_FORCE);
}

OPFUNC(pseudo_set)
{
	int r, v;

	// set MUST run on both passes as the symbol value changes!

	if (l -> sym == NULL)
	{
		register_error(as, l, 1, "No symbol specified");
		return;
	}

	r = lwasm_expr_result2(as, l, p, EXPR_PASS1CONST, &v, 0);
	if (r < 0)
		v = 0;

	l -> symaddr = v & 0xFFFF;
	l -> addrset = 2;
	
	lwasm_register_symbol(as, l, l -> sym, v, (r > 0 ? SYMBOL_COMPLEX: SYMBOL_NORM) | SYMBOL_SET);
}

OPFUNC(pseudo_setdp)
{
	int r, v;

	if (as -> outformat == OUTPUT_OBJ)
	{
		register_error(as, l, 1, "SETDP not permitted with OBJ target");
		return;
	}
	
	// setdp is needed on both passes; must resolve to a constant on pass 1
	r = lwasm_expr_result2(as, l, p, EXPR_PASS1CONST, &v, 0);
	if (r != 0)
		return;

	if (v < -127 || v > 255)
	{
		register_error(as, l, 1, "Byte overflow");
		return;
	}
	
	l -> symaddr = v & 0xFF;
	l -> addrset = 2;
	
	as -> dpval = v & 0xFF;
}

OPFUNC(pseudo_fcc)
{
	int delim = 0;
				
	delim = **p;
	if (!delim)
	{
		register_error(as, l, 1, "Bad operand");
		return;
	}
	*p += 1;
	while (**p && **p != delim)
	{
		lwasm_emit(as, l, **p);
		(*p)++;
	}
	if (**p)
		(*p)++;
}
		

OPFUNC(pseudo_fcs)
{
	int delim = 0;

	delim = **p;
	if (!delim)
	{
		register_error(as, l, 1, "Bad operand");
		return;
	}
	*p += 1;
	while (**p && **p != delim)
	{
		if (!*((*p) + 1) || *((*p) + 1) == delim)
			lwasm_emit(as, l, **p | 0x80);
		else
			lwasm_emit(as, l, **p);
		(*p)++;
	}
	if (**p)
		(*p)++;
}

OPFUNC(pseudo_fcn)
{		
	int delim = 0;
				
	delim = **p;
	if (!delim)
	{
		register_error(as, l, 1, "Bad operand");
		return;
	}
	*p += 1;
	while (**p && **p != delim)
	{
		lwasm_emit(as, l, **p);
		(*p)++;
	}
	if (**p)
		(*p)++;
	lwasm_emit(as, l, 0);
}

// FIXME: handle external, etc., references in a useful manner
OPFUNC(pseudo_fcb)
{
	int r, v;
	
fcb_again:
	r = lwasm_expr_result2(as, l, p, 0, &v, -1);
	if (r < 0)
		return;

	if (r > 0)
	{
		register_error(as, l, 2, "Illegal external or inter-segment reference");
		v = 0;
	}

	if (v < -127 || v > 255)
	{
		register_error(as, l, 1, "Byte overflow");
	}
	
	lwasm_emit(as, l, v);
	if (**p == ',')
	{
		(*p)++;
		goto fcb_again;
	}
}

// FIXME: handle external references in an intelligent way
OPFUNC(pseudo_fdb)
{			
	int r, v;
	
fdb_again:
	r = lwasm_expr_result2(as, l, p, 0, &v, -1);
	if (r < 0)
		return;

	if (r > 0)
	{
		register_error(as, l, 2, "Illegal external or inter-segment reference");
		v = 0;
	}

	lwasm_emit(as, l, v >> 8);
	lwasm_emit(as, l, v & 0xff);
	if (**p == ',')
	{
		(*p)++;
		goto fdb_again;
	}
}

// FIXME: handle external references in a sensible way
OPFUNC(pseudo_fqb)
{	
	int r, v;
	
fqb_again:
	r = lwasm_expr_result2(as, l, p, 0, &v, -1);
	if (r < 0)
		return;

	if (r > 0)
	{
		register_error(as, l, 2, "Illegal external or inter-segment reference");
		v = 0;
	}

	lwasm_emit(as, l, v >> 24);
	lwasm_emit(as, l, v >> 16);
	lwasm_emit(as, l, v >> 8);
	lwasm_emit(as, l, v & 0xff);
	if (**p == ',')
	{
		(*p)++;
		goto fqb_again;
	}
}

// don't need to do anything if we are executing one of these
OPFUNC(pseudo_endc)
{
	if (as -> skipcond && !(as -> skipmacro))
	{
		as -> skipcount -= 1;
		if (as -> skipcount <= 0)
		{
			as -> skipcond = 0;
		}
	}
	return;
}

// if "else" executes, we must be going into an "ignore" state
OPFUNC(pseudo_else)
{
	if (as -> skipmacro)
		return;
	
	if (as -> skipcond)
	{
		if (as -> skipcount == 1)
		{
			as -> skipcount = 0;
			as -> skipcond = 0;
		}
		return;
	}
	
	as -> skipcond = 1;
	as -> skipcount = 1;
}

OPFUNC(pseudo_ifne)
{
	int v1;
	int rval;

	if (as -> skipcond && !(as -> skipmacro))
	{
		as -> skipcount++;
		return;
	}

	rval = lwasm_expr_result2(as, l, p, EXPR_PASS1CONST, &v1, 0);
	if (rval != 0)
		return;
	if (!v1)
	{
		as -> skipcond = 1;
		as -> skipcount = 1;
	}
}

OPFUNC(pseudo_ifeq)
{
	int v1;
	int rval;

	if (as -> skipcond && !(as -> skipmacro))
	{
		as -> skipcount++;
		return;
	}

	rval = lwasm_expr_result2(as, l, p, EXPR_PASS1CONST, &v1, 0);
	if (rval != 0)
		return;
	if (v1)
	{
		as -> skipcond = 1;
		as -> skipcount = 1;
	}
}

OPFUNC(pseudo_iflt)
{
	int v1;
	int rval;

	if (as -> skipcond && !(as -> skipmacro))
	{
		as -> skipcount++;
		return;
	}

	rval = lwasm_expr_result2(as, l, p, EXPR_PASS1CONST, &v1, 0);
	if (rval != 0)
		return;
	if (v1 >= 0)
	{
		as -> skipcond = 1;
		as -> skipcount = 1;
	}
}

OPFUNC(pseudo_ifle)
{
	int v1;
	int rval;

	if (as -> skipcond && !(as -> skipmacro))
	{
		as -> skipcount++;
		return;
	}

	rval = lwasm_expr_result2(as, l, p, EXPR_PASS1CONST, &v1, 0);
	if (rval != 0)
		return;
	if (v1 > 0)
	{
		as -> skipcond = 1;
		as -> skipcount = 1;
	}
}

OPFUNC(pseudo_ifgt)
{
	int v1;
	int rval;

	if (as -> skipcond && !(as -> skipmacro))
	{
		as -> skipcount++;
		return;
	}

	rval = lwasm_expr_result2(as, l, p, EXPR_PASS1CONST, &v1, 0);
	if (rval != 0)
		return;
	if (v1 <= 0)
	{
		as -> skipcond = 1;
		as -> skipcount = 1;
	}
}

OPFUNC(pseudo_ifge)
{
	int v1;
	int rval;

	if (as -> skipcond && !(as -> skipmacro))
	{
		as -> skipcount++;
		return;
	}

	rval = lwasm_expr_result2(as, l, p, EXPR_PASS1CONST, &v1, 0);
	if (rval != 0)
		return;
	if (v1 < 0)
	{
		as -> skipcond = 1;
		as -> skipcount = 1;
	}
}

OPFUNC(pseudo_error)
{
	register_error(as, l, 1, "User error: %s", *p);
}


OPFUNC(pseudo_section)
{
	sectiontab_t *s;
	char *p2;
	char *sn;
	char *opts;
	
	
	if (as -> outformat != OUTPUT_OBJ)
	{
		register_error(as, l, 1, "Sections only supported for obj target");
		return;
	}
	
	if (as -> csect)
	{
		as -> csect -> offset = as -> addr;
		as -> csect = NULL;
	}
	
	if (!**p)
	{
		register_error(as, l, 1, "Need section name");
		return;
	}
	
	for (p2 = *p; *p2 && !isspace(*p2); p2++)
		/* do nothing */ ;
	
	sn = lwasm_alloc(p2 - *p + 1);
	memcpy(sn, *p, p2 - *p);
	sn[p2 - *p] = '\0';
	
	*p = p2;
	
	opts = strchr(sn, ',');
	if (opts)
	{
		*opts++ = '\0';
	}
	
	// have we seen the section name already?
	for (s = as -> sections; s; s = s -> next)
	{
		if (!strcmp(s -> name, sn))
			break;
	}
	
	if (s)
	{
		lwasm_free(sn);
		if (opts)
		{
			register_error(as, l, 1, "Section options can only be specified the first time");
			return;
		}
	}
	else if (!s)
	{
		s = lwasm_alloc(sizeof(sectiontab_t));
		s -> name = sn;
		s -> offset = 0;
		s -> flags = 0;
		
		// parse options; only one "bss"
		if (opts && as -> passnum == 1)
		{
			if (!strcasecmp(opts, "bss"))
			{
				s -> flags = SECTION_BSS;
			}
			else
			{
				register_error(as, l, 1, "Unrecognized section option '%s'", opts);
				lwasm_free(s -> name);
				lwasm_free(s);
				return;
			}
		}
		
		s -> next = as -> sections;
		as -> sections = s;
	}
	as -> addr = s -> offset;
	as -> csect = s;
	as -> context = lwasm_next_context(as);
}

OPFUNC(pseudo_endsection)
{
	if (as -> outformat != OUTPUT_OBJ)
	{
		register_error(as, l, 1, "Sections only supported for obj target");
		return;
	}
	
	if (!(as -> csect))
	{
		register_error(as, l, 1, "ENDSECTION when not in a section");
		return;
	}
	
	as -> csect -> offset = as -> addr;
	as -> addr = 0;
	as -> csect = 0;
	as -> context = lwasm_next_context(as);
}

OPFUNC(pseudo_extern)
{
	if (as -> passnum != 1)
		return;

	if (as -> outformat != OUTPUT_OBJ)
	{
		register_error(as, l, 1, "External references only supported for obj target");
		return;
	}
	
	if (as -> csect)
	{
		register_error(as, l, 1, "Cannot declare external symbols within a section");
		return;
	}
	
	lwasm_register_symbol(as, l, l -> sym, 0, SYMBOL_EXTERN);
}