I've reworked the assert to be explicit about checking the integer range could fit in a signed 8 bit value in commit https://github.com/silnrsi/grcompiler/commit/a60a04691c42f3f99543c83f9911c84e44a268fe
Hopefully this will fix the issue and it isn't really managing to generate an offset outside the -128 <->127 range. -- Tim Eves Writing Systems Technology - SIL International
