001    /*
002     *  This file is part of the Jikes RVM project (http://jikesrvm.org).
003     *
004     *  This file is licensed to You under the Eclipse Public License (EPL);
005     *  You may not use this file except in compliance with the License. You
006     *  may obtain a copy of the License at
007     *
008     *      http://www.opensource.org/licenses/eclipse-1.0.php
009     *
010     *  See the COPYRIGHT.txt file distributed with this work for information
011     *  regarding copyright ownership.
012     */
013    package org.jikesrvm;
014    
015    import org.vmmagic.unboxed.*;
016    
017    /**
018     * Constants defining heap layout constants
019     */
020    public interface HeapLayoutConstants {
021    
022      /** The address of the start of the data section of the boot image. */
023      Address BOOT_IMAGE_DATA_START =
024        Address.fromIntZeroExtend( 0x57000000 );
025    
026      /** The address of the start of the code section of the boot image. */
027      Address BOOT_IMAGE_CODE_START =
028        Address.fromIntZeroExtend( 0x5B000000 );
029    
030      /** The address of the start of the ref map section of the boot image. */
031      Address BOOT_IMAGE_RMAP_START =
032        Address.fromIntZeroExtend( 0x5E000000 );
033    
034      /** The address in virtual memory that is the highest that can be mapped. */
035      Address MAXIMUM_MAPPABLE =
036        Address.fromIntZeroExtend( 0xa0000000 );
037    
038      /** The maximum boot image data size */
039      int BOOT_IMAGE_DATA_SIZE = 56<<20;
040    
041      /** The maximum boot image code size */
042      int BOOT_IMAGE_CODE_SIZE = 24<<20;
043    
044      /* Typical compression ratio is about 1/20 */
045      int BAD_MAP_COMPRESSION = 5;  // conservative heuristic
046      int MAX_BOOT_IMAGE_RMAP_SIZE = BOOT_IMAGE_DATA_SIZE/BAD_MAP_COMPRESSION;
047    
048      /** The address of the end of the data section of the boot image. */
049      Address BOOT_IMAGE_DATA_END = BOOT_IMAGE_DATA_START.plus(BOOT_IMAGE_DATA_SIZE);
050      /** The address of the end of the code section of the boot image. */
051      Address BOOT_IMAGE_CODE_END = BOOT_IMAGE_CODE_START.plus(BOOT_IMAGE_CODE_SIZE);
052      /** The address of the end of the ref map section of the boot image. */
053      Address BOOT_IMAGE_RMAP_END = BOOT_IMAGE_RMAP_START.plus(MAX_BOOT_IMAGE_RMAP_SIZE);
054      /** The address of the end of the boot image. */
055      Address BOOT_IMAGE_END = BOOT_IMAGE_RMAP_END;
056    }