simon987/Much-Assembly-Required
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Merge pull request #144 from mlaga97/ram-corruption

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Implement RAM corruption effect
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Simon Fortier 2018-04-01 22:18:15 -04:00 committed by GitHub
commit 227f7ce5aa
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1 changed files with 27 additions and 0 deletions
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Server/src/main/java/net/simon987/server/assembly/Memory.java
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@ -13,6 +13,7 @@ import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.util.Arrays;
import java.util.Base64;
import java.util.Random;
import java.util.zip.Deflater;
import java.util.zip.DeflaterOutputStream;
import java.util.zip.Inflater;
@ -87,6 +88,32 @@ public class Memory implements Target, MongoSerialisable {
words[address] = (char) value;
}
/**
* Configurably corrupt memory
*
* @param blockSize Block size (in words) in which to randomly flip one bit
*/
public void corrupt(int blockSize) {
Random rand = new Random();
// Increment offset by blockSize
for (int offset = 0; offset < words.length; offset += blockSize) {
// Calculate address to corrupt by adding a random value between 0 to (blocksize-1) to offset
int address = rand.nextInt(blockSize) + offset;
// Checking here avoids having a protected area at the end of the address space
if(address < words.length) {
// Calculate bitmask by left-shifting 1 by a random value between 0 and 15
int bitmask = 1 << rand.nextInt(16);
// Flip the bit with XOR
words[address] ^= bitmask;
}
}
}
/**
* Fill the memory with 0s
*/