Where Is The Mmu - HP MC68040 User Manual

Chapter 10: Using Memory Management
Understanding Emulation and Analysis Of The Memory Management Unit
As pages are swapped back and forth between an external storage device and the
physical memory, the relationship between any one logical address and its
corresponding physical address may change many times.
Your HP emulator will let you run a paged, dynamic system, but the analyzer will
not be able to provide support for such features as symbolic addresses, or display of
corresponding source files. The deMMUer cannot detect changes in the MMU
mappings. The longer the system runs, the further out of date the deMMUer will
become. Of course, the analyzer will still be able to show activity captured at
physical addresses. By experimenting with several starting points for the inverse
assembler, you can obtain a trace list with activity inverse assembled into an
equivalent assembly language listing (display trace
disassemble_from_line_number <NO.> [low_word]).

Where Is The MMU?

The MMU is located between the CPU core and the external address bus. The
program counter always contains logical address values. When the MMU is turned
off, the program counter value is placed directly on the address bus to access an
address in physical memory. When the MMU is turned on, the MMU accepts the
logical address value and translates it (by using its translation tables) to a physical
address. The physical address from the MMU is placed on the processor address
bus.
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