Thread Safe EEPROM Simulator

Specifications

EEPROM is of 64Kb with 8192 words of 8 bits. The memory has 32 bytes page access. There are total 256 pages.

There are 2 API functions.

• void eeprom_read(uint32_t offset, int size, char *buf)

• void eeprom_write(uint32_t offset, int size, char *buf)

The offset is the total memory offset, size is buffer size that is to be read or written. *buf is the pointer to the start of the buffer. In read operation, data is read from eeprom and copied to buf. In write operation, data from buf is written to the eeprom.

Code Architecture and Assumptions

• The eeprom library makes use of file read and write functions to acces one page in a single operation.

• The required page number and page offset is calculated from the input memory offset.

• If the operations is spread over multiple pages, the page is accessed one by one and data is transferred from the buffer atmost one page per time.

• When multiple threads are accessing the simulated eeprom, critical section is defined only for a single page operation and not the entire write or read operation.

• Autheticity of the data going in and out of the eeprom is deterimined by the successful page operations.

• The simulated eeprom is filled by 0xFF during its initialisation.

• The write operation generated arftifical data with ascii value between 97 - 123. This is chosen for the simplicity of visualisation and the logic is idependednt of the byte value.

• Trace files are generated using random number generator with different ranges as per required.

Compilations and Usage

Assuming we are in the directory of the project.

• Compiling the code base. terminal> make

• Running for above specifications. terminal> make run

• Clearing object files and simuated .txt file terminal> make clean

• Running with default values will run a total of 8 trace file simultaneously with a dedicated thread for each file.

• The verbose flag is turned ON by default. This will print all the details of the operations performed. It will print the buffer if the size is less than 100.

• The simulated eeprom .txt file will have new line for each page. This is meant for the simplicity of the manual check if required.

• The code can also be executed with custom parameters for any specific trace file. Command line flags include -p defining page size in bytes -n total number of pages -t path of trace file -v verbose flag

• The following command will create eeprom with 512 pages with 16 bytes each and run only the read_small trace file while printing all the details. terminal> ./main -p 16 -n 512 -v 1 -t traces/read_small.trace

• Failing to specifiy any parameter in comman line options, will assume the default value for the parameter.

Testing

Apple clang version 11.0.3 (clang-1103.0.32.62) Target: x86_64-apple-darwin19.6.0 Thread model: posix.

Multiple memory trace files are generated that simulated read and writes of various sizes. It also tests for some of the edge cases that might occur in real life executions.

• toy.trace - Tests a total of 20 read/write operations with memory offset less than 127 bytes and size less than 10 bytes.

• read_small.trace - Tests a total of 200 read operations with memory offset and size less than 127 bytes.

• write_small.trace - Tests a total of 200 write operations with memory offset and size less than 127 bytes.

• test_small.trace - Tests a total of 200 read/write operations with memory offset and size less than 127 bytes.

• read_big.trace - Tests a total of 200 read operations with memory offset and size upto 8192 bytes.

• write_big.trace - Tests a total of 200 write operations with memory offset and size upto 8192 bytes.

• test_big.trace - Tests a total of 200 read/write operations with memory offset and size upto 8192 bytes.

• edge.trace - Tests a total of 200 read/write operations with corner cases including memory offset out of bounds, memory offset in bounds but size exceed the remaining capacity of the memory ,size = 0, size less than page size, size less than page size but operation spread across 2 pages.