Features; Virtual Memory - Motorola CPU32 Reference Manual

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1.1 Features
Features of the CPU32 are as follows:
• Fully Upward Object Code Compatible with M68000 Family
• Virtual Memory Implementation
• Loop Mode of Instruction Execution
• Fast Multiply, Divide, and Shift Instructions
• Fast Bus Interface with Dynamic Bus Port Sizing
• Improved Exception Handling for Controller Applications
• Enhanced Addressing Modes
- Scaled Index
- Address Register Indirect with Base Displacement and Index
- Expanded PC Relative Modes
- 32-Bit Branch Displacements
• Instruction Set Enhancements
- High-Precision Multiply and Divide
- Trap On Condition Codes
- Upper and Lower Bounds Checking
• Enhanced Breakpoint Instruction
• Trace on Change of Flow
• Table Lookup and Interpolate Instruction
• Low-Power Stop Instruction
• Hardware Breakpoint Signal, Background Mode
• 16.77-MHz Operating Frequency (-40 to 125°C)
• Fully Static Implementation
1.1.1 Virtual Memory
A system that supports virtual memory has a limited amount of high-speed
physical memory that can be accessed directly by the processor and maintains
an image of a much larger "virtual" memory on a secondary storage device.
When the processor attempts to access a location in the virtual memory map
that is not resident in physical memory, a page fault occurs. The access to that
location is temporarily suspended while the necessary data is fetched from
secondary storage and placed in physical memory. The suspended access is
then restarted or continued. The CPU32 uses instruction restart, which requires
that only a small portion of the internal machine state be saved. After correcting
the fault, the machine state is restored, and the instruction is refetched and
restarted. This process is completely transparent to the application program.
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CPU32 REFERENCE MANUAL