Going to use ATmega328P as an example.
It has all of its CPU and IO registers memory address mapped on an SRAM. A section of this SRAM is also used as volatile memory used by the stack.
The term "register" is a bit ambiguous for me here. Comparing it with x86 which usually uses SRAM as internal CPU registers and DRAM as memory somewhere on the bus (SRAM being much faster).
But in AVR everything seems to be placed on a gigantic SRAM which acts both as a register and memory? Is there a difference between AVR SRAM and the type of SRAM used in an x86 CPU?