Memory Hierarchy Q.69
Consider a machine a 2-way set associative data cache
of size 64 Kbytes and block size 16 bytes. The cache is
managed using 32 bit virtual addressed and the page
size is 4 Kybytes. A program to be run on this machine
begins as follows :
double APR {1024] [1024]
int i, j ;
/ * Initalize array APR to 0.0*/
for (i = 0; i < 1024; i ++)
for (j = 0; j < 1024; j++
APR [i] [j] = 0.0;
The size of double 8 bytes. Array APR is memory
starting at the beginning of virtual page 0 × FF000
and stored in row major order. The cache is initially
empty and no pre-fetching is done. The only data
memory references made by the program are those to
array APR.
0. Which of the following array elements has the same cache index as APR [0] [0] ?
- Option : B
- Explanation : ARR[0][0] i s located at virtual address 0xFF000000. Here FF000 is page address and 000 is page offset. So, index bits are 00000000000 Address of ARR[4][0] = 0xFF000 + 4 * 1024* size of (double) [since we use row major storage] = 0xFF000000 + 4096 * 8 = 0xFF000000 + 0x8000 = 0xFF008000 ( index bits matches that of ARR[0][0] as both read 00000000000)
