view lwasm/os9.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 928c033c0cd0
line wrap: on
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/*
os9.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 related to OS9 target
*/
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <lw_expr.h>

#include "lwasm.h"
#include "instab.h"


// OS9 syscall
PARSEFUNC(pseudo_parse_os9)
{
	lw_expr_t e;
	
	if (as -> output_format != OUTPUT_OS9 && as -> output_format != OUTPUT_OBJ)
	{
		lwasm_register_error2(as, l, E_DIRECTIVE_OS9_ONLY, "%s", "os9");
		return;
	}
	
	// fetch immediate value
	e = lwasm_parse_expr(as, p);
	if (!e)
	{
		lwasm_register_error(as, l, E_OPERAND_BAD);
		return;
	}
	lwasm_save_expr(l, 0, e);
	l -> len = 3;
}

EMITFUNC(pseudo_emit_os9)
{
	lw_expr_t e;
	
	e = lwasm_fetch_expr(l, 0);

	lwasm_emitop(l, 0x103f);
	lwasm_emitexpr(l, e, 1);
}

PARSEFUNC(pseudo_parse_mod)
{
	lw_expr_t e;
	int i;
	
	if (as -> output_format != OUTPUT_OS9)
	{
		lwasm_register_error2(as, l, E_DIRECTIVE_OS9_ONLY, "%s", "mod");
		skip_operand(p);
		return;
	}
	
	if (as -> inmod)
	{
		lwasm_register_error(as, l, E_MODULE_IN);
		skip_operand(p);
		return;
	}

	// parse 6 expressions...
	for (i = 0; i < 5; i++)
	{
		e = lwasm_parse_expr(as, p);
		if (!e)
		{
			lwasm_register_error(as, l, E_OPERAND_BAD);
			return;
		}

		lwasm_save_expr(l, i, e);

		if (**p != ',')
		{
			lwasm_register_error(as, l, E_OPERAND_BAD);
			return;
		}
		(*p)++;
	}

	e = lwasm_parse_expr(as, p);
	if (!e)
	{
		lwasm_register_error(as, l, E_OPERAND_BAD);
		return;
	}
	lwasm_save_expr(l, 5, e);

	l -> inmod = 1;
	
	// we have an implicit ORG 0 with "mod"
	lw_expr_destroy(l -> addr);
	l -> addr = lw_expr_build(lw_expr_type_int, 0);

	// likewise for data pointer
	lw_expr_destroy(l -> daddr);
	l -> daddr = lw_expr_build(lw_expr_type_int, 0);

	// init crc
	as -> inmod = 1;
	
	l -> len = 13;
}

EMITFUNC(pseudo_emit_mod)
{
	lw_expr_t e1, e2, e3, e4;
	int csum;
	
	as -> crc[0] = 0xff;
	as -> crc[1] = 0xff;
	as -> crc[2] = 0xff;

	// sync bytes
	lwasm_emit(l, 0x87);
	lwasm_emit(l, 0xcd);
	
	// mod length
	lwasm_emitexpr(l, e1 = lwasm_fetch_expr(l, 0), 2);
	
	// name offset
	lwasm_emitexpr(l, e2 = lwasm_fetch_expr(l, 1), 2);
	
	// type
	lwasm_emitexpr(l, e3 = lwasm_fetch_expr(l, 2), 1);
	
	// flags/rev
	lwasm_emitexpr(l, e4 = lwasm_fetch_expr(l, 3), 1);
	
	// header check
	csum = ~(0x87 ^ 0xCD ^(lw_expr_intval(e1) >> 8) ^ (lw_expr_intval(e1) & 0xff)
		^ (lw_expr_intval(e2) >> 8) ^ (lw_expr_intval(e2) & 0xff)
		^ lw_expr_intval(e3) ^ lw_expr_intval(e4));
	lwasm_emit(l, csum);

	// module type specific output
	// note that these are handled the same for all so
	// there need not be any special casing
	
	// exec offset or fmgr name offset
	lwasm_emitexpr(l, lwasm_fetch_expr(l, 4), 2);
	
	// data size or drvr name offset
	lwasm_emitexpr(l, lwasm_fetch_expr(l, 5), 2);
}

PARSEFUNC(pseudo_parse_emod)
{
	skip_operand(p);
	if (as -> output_format != OUTPUT_OS9)
	{
		lwasm_register_error2(as, l, E_DIRECTIVE_OS9_ONLY, "%s", "emod");
		return;
	}
	
	if (!(as -> inmod))
	{
		lwasm_register_error(as, l, E_MODULE_NOTIN);
		return;
	}
	
	as -> inmod = 0;
	l -> len = 3;
}

EMITFUNC(pseudo_emit_emod)
{
	unsigned char tcrc[3];
	
	// don't mess with CRC!
	tcrc[0] = as -> crc[0] ^ 0xff;
	tcrc[1] = as -> crc[1] ^ 0xff;
	tcrc[2] = as -> crc[2] ^ 0xff;
	lwasm_emit(l, tcrc[0]);
	lwasm_emit(l, tcrc[1]);
	lwasm_emit(l, tcrc[2]);
}