SquirrelJME/SquirrelJME

// -*- Mode: Java; indent-tabs-mode: t; tab-width: 4 -*-
// ---------------------------------------------------------------------------
// SquirrelJME
//     Copyright (C) Stephanie Gawroriski <xer@multiphasicapps.net>
// ---------------------------------------------------------------------------
// SquirrelJME is under the Mozilla Public License Version 2.0.
// See license.mkd for licensing and copyright information.
// ---------------------------------------------------------------------------

package cc.squirreljme.emulator;

/**
 * This contains the implementation of some system calls in the event that the
 * JNI emulation layer does not have a C-based implementation of a method.
 *
 * @since 2020/02/26
 */
public final class EmulatorAssembly
{
    /** The thread contexts, storing thread specific information. */
    private static final ThreadLocal<EmulatorThreadContext> _CONTEXT =
        new ThreadLocal<>();
    
    /**
     * Not used.
     *
     * @since 2020/02/26
     */
    private EmulatorAssembly()
    {
    }
    
    /**
     * Handles system calls in Java.
     *
     * @param __si System call index.
     * @param __a Argument.
     * @param __b Argument.
     * @param __c Argument.
     * @param __d Argument.
     * @param __e Argument.
     * @param __f Argument.
     * @param __g Argument.
     * @param __h Argument.
     * @return The result.
     * @since 2020/02/26
     */
    public static long systemCall(short __si, int __a, int __b,
        int __c, int __d, int __e, int __f, int __g, int __h)
    {
        throw new Error("Invalid Emulator System Call");
    }
    
    /**
     * Returns the current thread context.
     *
     * @return The thread context.
     * @since 2020/02/26
     */
    public static EmulatorThreadContext threadContext()
    {
        // Has this been created already?
        EmulatorThreadContext rv = EmulatorAssembly._CONTEXT.get();
        if (rv != null)
            return rv;
        
        // Does not exist, needs to be created
        synchronized (EmulatorAssembly.class)
        {
            // Check again
            rv = EmulatorAssembly._CONTEXT.get();
            if (rv != null)
                return rv;
            
            EmulatorAssembly._CONTEXT.set((rv = new EmulatorThreadContext()));
            return rv;
        }
    }
}