What you'll learn

Cache lines move through states (MESI). Snoops and maintenance ops control those transitions.

• MESI states: Modified, Exclusive, Shared, Invalid — define what operations are legal.

• Cache-maintenance operation names, target points and completion rules come from the selected architecture and platform.

• DMA and memory-attribute transitions use platform ownership, mapping, maintenance and synchronisation contracts rather than one universal flush sequence.

Connection

Cache state theory applied to ACE/CHI snoop transactions.

Key diagram

Maintenance follows ownership, not a universal flush recipe

Study this topic

1. Concepts — rules and mental models

2. Integration — system contracts

3. Debug — trace the first divergence

4. Interview — explain and defend your answer