Answers at the bottom
- By having the cache act as a bridge between main memory and the CPU, the time it takes to retrieve a block of data from main memory is longer than it would be if the cache did not exist.
- True
- False
- Typically, a split cache divides both the L1 and L2 caches into an instruction-only cache and a data-only cache.
- True
- False
- Which is the fastest cache mapping function? Select all that apply.
- One-way set associative cache
- Direct-mapped cache
- Fully associative cache
- All of these
- Which cache mapping function(s) do not require a replacement algorithm? Select all that apply.
- One-way set associative cache
- Direct-mapped cache
- Fully associative cache
- All of these
- Consider this cache design:
- 1KB of cache
- 16-bit address
- Byte aligned
- 8 byte block
- Fully associative cache
How many bits would its tag and offset have?
- Consider this cache design:
- 1KB of cache
- 16-bit address
- Byte aligned
- 8 byte block
- Direct-mapped
How many bits would its tag, index, and offset have?
- Consider this cache design:
- 1KB of cache
- 16-bit address
- Byte aligned
- 8 byte block
- 4-way set associative
How many bits would its tag, index, and offset have?
- Consider this cache design:
- 1KB of cache
- 16-bit address
- Word aligned
- 64 byte block
- 2-way set associative
How many bits would its tag, index, and offset have?
- Suppose we have a cache with:
- 256 bytes of cache
- Byte aligned
- 16 bytes per cache line
- One-way set associative
Assume that the cache is initially empty. For each reference, write down the tag (in hex), index, whether that reference is a hit or miss, and the type of miss (compulsory or conflict).
| Memory address | Tag | Index | Hit/miss | Compulsory/conflict |
|---|---|---|---|---|
| 0x23ab | ||||
| 0xc31b | ||||
| 0xc31a | ||||
| 0xac7a |
- False
- True
- One-way set associative cache and direct-mapped cache
- One-way set associative cache and direct-mapped cache
- Tag: 13, offset: 3
- Tag: 6, index: 7, offset: 3
- Tag: 8, index: 5, offset: 3
- Tag: 9, index: 3, offset: 4
| Memory address | Tag | Index | Hit/miss | Compulsory/conflict |
|---|---|---|---|---|
| 0x23ab | 23 | a | Miss | Compulsory |
| 0xc31b | c3 | 1 | Miss | Conflict |
| 0xc31a | c3 | 1 | Hit | |
| 0xac7a | ac | 7 | Miss | Compulsory |