Memory / Cache 1) Supposed we have a 1KB direct-mapped data cache with 4 byte bl
ID: 3843260 • Letter: M
Question
Memory / Cache
1) Supposed we have a 1KB direct-mapped data cache with 4 byte blocks.
a. Show how a 32-bit memory address is divided into tag, index and offset. Show clearly how many bits are in each field.
b. How many total bits are there in this cache?
c. Consider this address trace:
0x807bfc4
0x807b1dc
0x907bfc4
0x806ce04
0x807b1e0
0x806ce0c
0x807b1e4
0x806ce0c
0x807bfc4
0x806ce14
For this cache, for each address in the above trace, show the tag, index and offset in binary. Indicate whether each reference is a hit or a miss. What is the miss rate?
Explanation / Answer
a. Show how a 32-bit memory address is divided into tag, index and offset. Show clearly how many bits are in each field.
b. How many total bits are there in this cache?
2offset = 22 bytes
=> offset = 2
Total cache size = 4 bytes 2index
=> 1KB / 4 = 2index
=> 2index = 210 / 4 = 28
index = 8 bits
=> Tag = 32 - 8 - 2 = 22
Tag : 22
Offset : 2
Index: 8
Total bits in Cache means the size which is 1KB = 210 => 10 bits
Thanks