1. cache behavior Consider an overly simplistic direct cache of 256 bytes arranged as 16 cache lines of 16 bytes each. Assume that the low order 4 bits of an address indicates the byte within the cache line and the next 4 bits indicate which cache line slot should be used. Assuming no useful data is in the cache at the beginning, how many cache misses will result from the following sequence of addresses being read from memory. Note each cache line that will be loaded into the cache in order. Show the state of the cache at the end of this activity. (each address is given in hexadecimal)

A memory system has 4 KB byte-addressable main memory and a direct-mapped cache that consists of 8 blocks with 16 bytes per block. The following shows the main memory address format that allows us to map addresses from main memory to cache. Note: 12 bit address, 4 bit offset, 3 bit $block, and 5 bit tag Assume the cache directory shown below:

3. Assuming a cache of 4096 blocks, a four-word block size, each word contains 4 bytes, and a 64-bits memory address. Memory is byte addressable, and random block replacement policy and write back policy are implemented. Find the total number of tag bits for caches that are a) direct-mapped b) 2-way set associative c) 4-way set associative d) Fully associative

Assume the address format for a fully-associative cache is as follows: 6 bits 2 bits Tag Offset 8 bits Given the cache directory is as shown in the diagram below, indicate whether the memory reference Ox5E results in a cache hits or a miss. Tag valid Block 000 110110 001 000001 010 000010 011 000101 100 001000 1 101 100010 110 010111 111 110110 O Hit O Miss

It is important to make a distinction between caches that are fully associative and caches that are directly mapped.

1. Caches are important to providing a high-performance memory hierarchy to processors. Below is a list of 32-bit memory address references, given as word addresses. 42, 137, 66, 50, 38, 225, 173, 22, 19, 88, 51, 43 a. For each of these references, identify the binary address, the tag, and the index given a direct mapped cache with 16 one-word blocks. Also list if each reference is a hit or a miss, assuming the cache is initially empty. b. For each of these references, identify the binary address, the tag, and the index given a direct mapped cache with two-word blocks and a total size of 8 blocks. Also list if each reference is a hit or a miss, assuming the cache is initially empty. Please explain the process.

Assume a cache of 1 MB organized as 32 bytes each line. The main memory is 256 MB. a. Determine the number of blocks in main memory b. Determine how to split the address (s-r, r, w) for direct mapping. c. Determine how to split the address (s, w) for associative mapping. d. Determine how to split the address (s-d, d, w) for set-associative each cache set is 4 lines of the cache.

Question 23 Some portion of cache system A represented below. The system is byte-addressable and the block size is one word (4 bytes). The tag and line number are represented with a binary numbers. The contents of words in the block are represented with hexadecimal. Tag 10 1000 0100 1001 10 1000 0100 1001 10 1000 0100 1001 10 1000 0100 1101 Line Number 0110 1101 0110 1110 0110 1111 B1 FF B8 A1 FF B8 B1 FF B8 A1 FF B8 B1 FF B8 0111 0000 1. What is the size of the main memory of this system? 2. What is the size of the cache memory of this system? 00 Word within block 2016 6116 C116 2116 01 10 11 3216 7216 C216 D216 4216 8216 4116 A216 E216 9216 5216 B216 3. If the CPU requests to read memory address A1 25 BA, what data does the CPU receive? 4. If the CPU requests to read memory address A1 35 C2, what data does the CPU receive? 5. If we access memory in the following order in cache system A: A1 FF B8 how many cache misses would occur for the data request?

The low order 4 bits of the address indicate location in the cache line and the next 4 bits indicate which line in the cache should be used and the remaining bits of the address are used as the cache tag. If the following addresses are read in this order, indicate (circle or similar) each one that would result in a cache miss. 2A1220 2A122C B14408 B14428 2A122C