src.org.tukaani.xz.simple.PowerPC Maven / Gradle / Ivy
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/*
* BCJ filter for big endian PowerPC instructions
*
* Authors: Lasse Collin
* Igor Pavlov
*
* 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;
}
}
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