3. Below is the sequence of HEX word address accesses made to a 256x8 DRAM by a
ID: 3822016 • Letter: 3
Question
3. Below is the sequence of HEX word address accesses made to a 256x8 DRAM by a CPU with a direct mapped 2 word block, 4-block cache:
88, 8c, 87, 82, 8c, 82, 85, 87, 86, 84, a3, a2, a9, a7, a4
a6, a7, ac, 80, 80, 8e, 89, 86, 80, 8d
The cache is completely empty before the sequence of word address accesses. Find the hit ratio as a percentage and the state of the cache after the sequence of word address accesses. Leave a cell blank if it does not contain valid data.
Hit ratio:____
Offset Offset Tag Index 0 1 00 01 10 11Explanation / Answer
To solve this problem we will follow below rule :-
Below table is following above rule and updating CACHE .
Final Answer :-
Offset
Offset
Tag
Index
1
0
11
00
81
80
01
01
a3
a2
100
10
8d
8c
00
11
87
86
Hit Ratio :- 9/16
Hex
decimal
Mod 8
HIT/MISS
88
136
0
Miss
88 along with 89 will be inserted in 0 &1
8c
140
4
Miss
8c along with 8d will be inserted in 4 &5
87
135
7
Miss
87along with 86 will be inserted in 6&7
82
130
2
Miss
82 along with 83 will be inserted in 2&3
8c
140
4
Hit
8c already present
82
130
2
Hit
82 already present
85
133
5
Miss
85 along with 84 will be inserted in 5&4
(tag will change from 00->01)
87
135
7
Hit
87 already present
86
134
6
Hit
86 already present
84
132
4
Hit
84 already present
a3
163
3
Miss
a3 along with a2 will be inserted in 3&2
a2
162
2
Hit
a9
169
1
Miss
a7
167
7
Miss
a4
164
4
Miss
a6
166
6
Hit
a7
167
7
Hit
ac
172
4
Miss
80
128
0
Miss
80
128
0
Hit
8e
142
6
Miss
89
137
1
Miss
86
134
6
Miss
80
128
0
Miss
8d
141
5
Miss
Offset
Offset
Tag
Index
1
0
00
1
0
00
3
2
00
5
4
00
7
6
1
Offset
Offset
Tag
Index
1
0
00
00
89
88
01
3
2
10
5
4
11
7
6
5
Offset
Offset
Tag
Index
1
0
00
00
89
88
00
01
83
82
01
10
85
84
00
11
87
86
2
Offset
Offset
Tag
Index
1
0
00
00
89
88
01
3
2
00
10
8d
8c
11
7
6
6
Offset
Offset
Tag
Index
1
0
00
00
89
88
01
01
a3
a2
01
10
85
84
00
11
87
86
3
Offset
Offset
Tag
Index
1
0
00
00
89
88
01
3
2
00
10
8d
8c
00
11
87
86
4
Offset
Offset
Tag
Index
1
0
00
00
89
88
00
01
83
82
00
10
8d
8c
00
11
87
86
Offset
Offset
Tag
Index
1
0
11
00
81
80
01
01
a3
a2
100
10
8d
8c
00
11
87
86
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