Question

Fill in the code for the following C functions. Function srl performs a logical right shifting using arithmetic right shift (given by value xsra), followed by other operations not including right shifts or division. Function sra performs an arithmetic right shift using a logical right shift (given by value xsrl), followed by other operations not including right shift or division. you may use the computation 8*size of (int) to determine w, the number of bits in data type int. The shift amount k can change from 0 to w-1.

unsigned srl (unsigned x, int k){

unsigned xsra = (int) x>> k;

.

.

.

}

int sra (int x, int k){

int xsrl = (unsigned) x >> k;

.

.

.

}

Answer 1

Solution:

#include <stdio.h>

unsigned srl(unsigned x, int k)

{

/* arithmetic right shifting */

unsigned xsra = (int) x >> k;

int w = sizeof(unsigned) << 3;

unsigned mask = ~(0xff << (w - k));

return xsra & mask;

}

int sra(int x, int k)

{

/* logical right shifting */

int xsrl = (unsigned) x >> k;

int w = sizeof(int) << 3;

unsigned sign = !!((0x1 << (w - 1)) & x);

unsigned mask = (~sign + 1) << (w - k);

return xsrl | mask;

}

//driver funtion to test

int main(int argc, char **argv)

{

printf("%.8x\n", srl(0x1 << 16, 8));

printf("%.8x\n", srl(~0x0, 6));

printf("%.8x\n", srl(0x0, 6));

printf("\n");

printf("%.8x\n", sra(0x9 << 26, 8));

printf("%.8x\n", sra(~0x0, 6));

printf("%.8x\n", sra(0x0, 6));

return 0;

}

Output:

Please give thumbsup, if you like it. Thanks.