public int getInstructionBytes(int offset, int bytestart, int size)
			throws MemoryAccessException {
		offset += bytestart;
		byte[] bytes = new byte[size]; // leave any unavailable bytes as 0 in result
		int readSize = memBuffer.getBytes(bytes, offset);
		if (offset == 0 && readSize == 0) {
			throw new MemoryAccessException("invalid memory");
		}
		int result = 0;
		for (int i = 0; i < size; i++) {
			result <<= 8;
			result |= bytes[i] & 0xff;
		}
		return result;
	}
Get bytes from the instruction stream into an int
(packed in big endian format).  Uninitialized or 
undefined memory will return zero byte values.
@param offset offset relative start of this context
@param bytestart pattern byte offset relative to specified context offset 
@param size is the number of bytes to fetch
@return requested byte-range value
@throws MemoryAccessException if no bytes are available at first byte when (offset+bytestart==0).
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/app/plugin/processors/sleigh/SleighParserContext.java