快速c算法的ints

I am writing a c program. I have an unsigned integer (16bit) whose value could be anything at any time and I have a signed char (8bit) whose value could be anything at any time, within the obvious limits of the data types. I need to add the signed char to the unsigned int, the result being an unsigned int, and if the value overflows either past 0xFFFF or below 0x00, i need the result to equal the limit (either 0x00 or 0xFFFF). I want to know what would be the fastest approach to doing this? My approach is shown below but it uses a long data type and thus long binary arithmetic so I am guessing that there is a faster way...I am writing a c program. I have an unsigned in