Question: Number of cycles to do a full contact switch save?

Answer: Depends on what is meant by "Full". Saving every single register is not normally done if it can be avoided by smart code writing. Minimal context switching of the accumulator and the 2 status registers takes approximately 5 cycles for save, 8 cycles for restore. Each auxiliary register adds 1 cycle save, 2 cycles restore. P and T registers combined add 5 cycles save, 5 cycles restore. There may also be a few overhead cycles to initialize a stack pointer or set the data page. Also, these numbers assume that the contexting is done in on-chip memory (external mem can have bus bottlenecks and/or wait-states).