private long getContextRegisterValue(CodeUnit cu, Register contextRegister) {
		ProgramContext context = cu.getProgram().getProgramContext();
		RegisterValue value = context.getRegisterValue(contextRegister, cu.getAddress());
		if (value != null) {
			return value.getUnsignedValue().longValue();
		}
		//we tried, return 0 to match SLEIGH default
		return 0;
	}
Get detailed instruction list for a block of instructions.

@param lang
           processor language (corresponding LanguageID must be defined
           within LanguageMap.txt)
@param blockAddr
           start of block ( must be true: (offset & -(2^blockSizeFactor)
           == offset)
@param blockSizeFactor
           the block size factor where blockSize = 2^blockSizeFactor
           (must be > 0)
@param byteProvider
           provider for block of bytes to be disassembled starting at
           offset 0
@return list of instructions or null if language not supported by GNU
        Disassembler
@throws Exception
Ghidra/Extensions/SleighDevTools/src/main/java/ghidra/app/util/disassemble/GNUExternalDisassembler.java