what the code/procedure is for printing out the CPU's/FPU's speed in Mhz (if it's possible with Amos programming)
There is no such procedure, nor is it possible to measure the system speed even remotely reliably with AMOS itself.
WhichAmiga.lha has some code that measures CPU frequency, it should be reliable on 020, 030, 040 and 060 at least. On 68000 and 68010 other parts of the system can slow down the execution of the timing loop, and thus give unreliable results.