You are writing a new 3D game that you hope will earn you fame andfortune. You are currently working on a function to blank the screenbuffer before drawing the next frame. The screen you are working withis a 640 × 480 array of pixels. The machine you are working on has a64 KB direct-mapped cache with 4-byte lines. The C structures youare using are as follows:1 struct pixel {2 char r;3 char g;4 char b;5 char a;6 };78 struct pixel buffer[480][640];9 int i, j;10 char *cptr;11 int *iptr;Assume the following:sizeof(char) = 1 and sizeof(int) = 4.buffer begins at memory address 0.The cache is initially empty.The only memory accesses are to the entries of the array buffer.Variables i, j, cptr , and iptr are stored in registers.What percentage of writes in the following code will miss in the cache?1 for (j = 0; j < 640; j++) {2 for (i = 0; i < 480; i++){3 buffer[i][j].r = 0;4 buffer[i][j].g = 0;5 buffer[i][j].b = 0;6 buffer[i][j].a = 0;7 }8 }
You are writing a new 3D game that you hope will earn you fame and
fortune. You are currently working on a function to blank the screen
buffer before drawing the next frame. The screen you are working with
is a 640 × 480 array of pixels. The machine you are working on has a
64 KB direct-mapped cache with 4-byte lines. The C structures you
are using are as follows:
1 struct pixel {
2 char r;
3 char g;
4 char b;
5 char a;
6 };
7
8 struct pixel buffer[480][640];
9 int i, j;
10 char *cptr;
11 int *iptr;
Assume the following:
sizeof(char) = 1 and sizeof(int) = 4.
buffer begins at memory address 0.
The cache is initially empty.
The only memory accesses are to the entries of the array buffer.
Variables i, j, cptr , and iptr are stored in registers.
What percentage of writes in the following code will miss in the cache?
1 for (j = 0; j < 640; j++) {
2 for (i = 0; i < 480; i++){
3 buffer[i][j].r = 0;
4 buffer[i][j].g = 0;
5 buffer[i][j].b = 0;
6 buffer[i][j].a = 0;
7 }
8 }
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