I am learning processor basics. I have this doubt.
If I have a processor with 9 one-byte instructions and one 2-bytes instruction in its instruction set architecture, should n't the instruction register of the processor be 16 bits instead of 8-bits ? Say for example:
2000 MOV A,B 2001 MVI C, 20h --- 2 byte instruction
In my book it says PC points to address 2003 after 2001. So it means, when PC was pointing to 2001, both the 8-bit immediate data and the 8-bit opcode were fetched into the instruction register in one go right ? Or is it fetched in two cycles ? Also I would like to know what is the significance of data and instruction caches in a processor. Is it neccesary in a processor ?