1 /* 2 * BCJ filter for SPARC instructions 3 * 4 * Authors: Lasse Collin <lasse.collin (at) tukaani.org> 5 * Igor Pavlov <http://7-zip.org/> 6 * 7 * This file has been put into the public domain. 8 * You can do whatever you want with this file. 9 */ 10 11 package org.tukaani.xz.simple; 12 13 public final class SPARC implements SimpleFilter { 14 private final boolean isEncoder; 15 private int pos; 16 17 public SPARC(boolean isEncoder, int startPos) { 18 this.isEncoder = isEncoder; 19 pos = startPos; 20 } 21 22 public int code(byte[] buf, int off, int len) { 23 int end = off + len - 4; 24 int i; 25 26 for (i = off; i <= end; i += 4) { 27 if ((buf[i] == 0x40 && (buf[i + 1] & 0xC0) == 0x00) 28 || (buf[i] == 0x7F && (buf[i + 1] & 0xC0) == 0xC0)) { 29 int src = ((buf[i] & 0xFF) << 24) 30 | ((buf[i + 1] & 0xFF) << 16) 31 | ((buf[i + 2] & 0xFF) << 8) 32 | (buf[i + 3] & 0xFF); 33 src <<= 2; 34 35 int dest; 36 if (isEncoder) 37 dest = src + (pos + i - off); 38 else 39 dest = src - (pos + i - off); 40 41 dest >>>= 2; 42 dest = (((0 - ((dest >>> 22) & 1)) << 22) & 0x3FFFFFFF) 43 | (dest & 0x3FFFFF) | 0x40000000; 44 45 buf[i] = (byte)(dest >>> 24); 46 buf[i + 1] = (byte)(dest >>> 16); 47 buf[i + 2] = (byte)(dest >>> 8); 48 buf[i + 3] = (byte)dest; 49 } 50 } 51 52 i -= off; 53 pos += i; 54 return i; 55 } 56 } 57
