jodd-proxetta/src/main/java/jodd/asm7/ClassReader.java
public long readLong(final int offset) {
    long l1 = readInt(offset);
    long l0 = readInt(offset + 4) & 0xFFFFFFFFL;
    return (l1 << 32) | l0;
  }
public long readLong(final int offset) {
    long l1 = readInt(offset);
    long l0 = readInt(offset + 4) & 0xFFFFFFFFL;
    return (l1 << 32) | l0;
  }
Reads a signed long value in {@link #b}. <i>This method is intended for {@link Attribute} sub
classes, and is normally not needed by class generators or adapters.</i>

@param offset the start offset of the value to be read in {@link #b}.
@return the read value.