[jezze]

Yeah I am not advocating creating a new seperate register, even though that would be nice. Like the poster below said, there are usually some unpreserved registers to choose from but if you for some reason cant spare a register you could instead write the error code to any virtual address instead, or send a signal, a message or anything else you could come up with. Just some way that does away with this intermix of return types and error types.