| /* |
| * BCJ filter for big endian PowerPC instructions |
| * |
| * Authors: Lasse Collin <lasse.collin@tukaani.org> |
| * Igor Pavlov <http://7-zip.org/> |
| * |
| * This file has been put into the public domain. |
| * You can do whatever you want with this file. |
| */ |
| |
| package org.tukaani.xz.simple; |
| |
| public final class PowerPC implements SimpleFilter { |
| private final boolean isEncoder; |
| private int pos; |
| |
| public PowerPC(boolean isEncoder, int startPos) { |
| this.isEncoder = isEncoder; |
| pos = startPos; |
| } |
| |
| public int code(byte[] buf, int off, int len) { |
| int end = off + len - 4; |
| int i; |
| |
| for (i = off; i <= end; i += 4) { |
| if ((buf[i] & 0xFC) == 0x48 && (buf[i + 3] & 0x03) == 0x01) { |
| int src = ((buf[i] & 0x03) << 24) |
| | ((buf[i + 1] & 0xFF) << 16) |
| | ((buf[i + 2] & 0xFF) << 8) |
| | (buf[i + 3] & 0xFC); |
| |
| int dest; |
| if (isEncoder) |
| dest = src + (pos + i - off); |
| else |
| dest = src - (pos + i - off); |
| |
| buf[i] = (byte)(0x48 | ((dest >>> 24) & 0x03)); |
| buf[i + 1] = (byte)(dest >>> 16); |
| buf[i + 2] = (byte)(dest >>> 8); |
| buf[i + 3] = (byte)((buf[i + 3] & 0x03) | dest); |
| } |
| } |
| |
| i -= off; |
| pos += i; |
| return i; |
| } |
| } |