tbc@hp-lsd.COS.HP.COM (Tim Chambers) (11/15/89)
Hello, net readers. I am responsible for producing an instruction set
simulator/debugger for the Motorola MC68030. It is intended for software
engineers developing code for the MC68030 who need an execution/debug
environment but do not, for one reason or another, have access to the actual
chip. (It is based on the Microtec XRAY debugger/simulator, in case you're
more familiar with their products than ours.)
I would very much appreciate your opinions on the role a memory management
unit (MMU) plays in real-time systems.
1. Once the MMU becomes part of the processor chip and not an additional part
on the board, how do you envision it will be used in real-time systems?
In particular, for those using the MMU in the MC68030, here is what I am
curious to know.
2. Which of the following MC68030 assembly instructions are you using?
a. PFLUSH (yes or no)
b. PLOAD (yes or no)
c. PMOVE (yes or no)
d. PTEST (yes or no)
3. What purpose do you have for the MMU functionality in your system?
a. Protection of code and data protection using a flat address space in
which the logical address is identical to the physical address? (yes
or no)
b. Instantiation for handling more than one peripheral at once in which
multiple tasks reference an identical block of logical addresses that
are mapped to non-overlapping physical addresses representing
memory-mapped I/O? (yes or no)
c. Memory "banking" to handle D/A and A/D buffer dumps? (yes or no)
d. Virtual paged memory? (yes or no)
e. Other? (please explain)
4. Do you plan to use the function code lookup (FCL) feature of the MMU? If
so, for what purpose?
a. Protection of code and data protection using a flat address space in
which the logical address is identical to the physical address? (yes
or no)
b. Other? (please explain)
Please do not hesitate to ask me for an explanation of any part of the
questions that are not clear. I can also be reached at (719)590-5570.
Tim Chambers <tbc%hp-lsd@hplabs>
Software Engineer
Hewlett-Packard
Logic Systems Division
Colorado Springs, CO