how can we find that this processor supports how much memory?

Question

I have just started the Assembly language programming and in the first lecture our teacher told us about intel 8080 and intel 8085 and he said there was 64k memory with these processor.

Now i want to know that how we find this amount of memory with specific processor, for example i have a processor 1.8 Ghz , now how i can find out the amount of memory that can be used with this processor.

what i am trying to ask is tell me the method how we can find out this amount of memory?

Answer 1

It depends on how many bits of (physical) addressing the CPU supports, The number of address bits is typically <= the number of bits in an address register, e.g.

8085/Z80 - 16 bit address registers - 16 bit addressing - 64 kB address space
68008 - 32 bit address registers - 20 bit addressing - 1 MB address space
68000 - 32 bit address registers - 24 bit addressing - 16 MB address space
68020 - 32 bit address registers - 32 bit addressing - 4 GB address space

Note that many 64-bit CPUs typically only support something like a 40 bit address space, i.e. 1 TB.