I'm using CodeWarrior to develop C code for the MCF52233 ColdFire processor. I seems that the C compiler does not take advantage of registers D1-D7 and A2-A5. Is this seem correct? I have not optimization turned on and the parameter passing is "standard". Does register utilization improve if optimizations are turned on?
When calling a assembly functions from C code, since the compliler does not use the registers, would it safe (but perhaps sloppy) code not to perserve the register values since they are not used by the compiler?