Virtual Memory Manager Simulator

简体中文

This C11 simulator translates 16-bit logical addresses through a page table and a 16-entry translation lookaside buffer (TLB). It loads signed-byte values from a backing store, applies FIFO replacement to both the TLB and physical frames, and records translation statistics for a supplied address trace.

Features

• Configurable page size and physical frame count
• FIFO page replacement with invalidation of stale TLB entries
• FIFO TLB replacement without duplicate insertion on page faults
• Logical-to-physical address translation and signed-byte lookup
• Strict validation for configuration values, address traces, and input files
• Reproducible regression test using the included 1,000-address workload

Build and run

On Linux or macOS:

make
./mmu 10 32 > output.txt

On Windows with GCC:

gcc -std=c11 -O2 -Wall -Wextra -Wpedantic mmu_simulator.c -o mmu.exe
.\mmu.exe 10 32 > output.txt

The first argument is the number of offset bits, so 10 selects a 1,024-byte page. The second argument is the physical frame count. Running without arguments starts the interactive prompts.

The full command form accepts alternate fixture and output paths:

mmu frame-size-bits number-of-frames addresses-file backing-store statistics-file

Reference workload

The command ./mmu 10 32 processes the included files and writes these values to stat.txt:

Metric	Result
Logical addresses	1,000
Page faults	501
Page-fault rate	0.501000
TLB hits	234
TLB hit rate	0.234000

Detailed translations are written to standard output. Redirect them to a file when needed; generated executables, output.txt, and stat.txt are ignored by Git.

Test

On Linux or macOS:

make test

On Windows:

python tests/test_mmu.py .\mmu.exe

The test checks the reference statistics, rejects an invalid physical-memory configuration, and rejects a malformed address trace.

Repository contents

mmu_simulator.c        MMU simulator implementation
addresses.txt          Included logical-address trace
backingstore.bin       Included 65,536-byte backing store
tests/test_mmu.py      Standard-library regression test
Makefile               GCC build and test commands

Scope

The simulator models a single process with a 16-bit logical address space. It implements FIFO policies only and does not model dirty pages, write-back, protection bits, multilevel page tables, or concurrent memory accesses.

License

Source code and documentation are licensed under the MIT License. The supplied workload files are described separately in NOTICE.