This lab consists of a set of puzzles that work with bit-level representations and manipulations, and twos complement representation. The rules for completing lab include:

All of these problems can be done with the eight operators:

! ~ & ^ | + << >>

and some require you to stick with just a subset of these.

You are also limited to constants with length at most 8-bits

i.e. you are limited to constants with two hexadecimal digits.

You must use straight-line code no loops or conditionals.

Each puzzle also has a rating of 1 (easiest) to 4 (hardest).

There is a limit on the number of operations you may use (just to eliminate brute force solutions).

Each puzzle is worth 5 points

Sample Puzzles

Sample Puzzle One - tmin - return the minimum two's complement integer

Legal ops: ! ~ & ^ | + << >>

Max ops: 4

Rating: 1

The following code solves (& tests) this function.

#include

int tmin(void) {

return 1<<31;

}

int main() {

printf(Tests for sample puzzle one );

int x;

x = tmin();

printf(Tmin Decimal format %d , x);

printf(Tmin Hexadecimal format %x , x);

printf( );

return 0;

}

For Problem 8 is that right?

Puzzle Eight isLess - if x < y then return 1, else return 0

Example: isLess(4,5) = 1.

Legal ops: ! ~ & ^ | + << >>

Max ops: 30

Rating: 3

isLess(int x, int y) {

return ((((x+((~y)+1))>>31)+1);

}

Problem 9 I need help with

Puzzle Nine threeFourths - multiplies by 3/4 rounding toward 0,

Should exactly duplicate effect of C expression (x*3/4), including overflow behavior.

Examples: ezThreeFourths(11) = 8

ezThreeFourths(-9) = -6

ezThreeFourths(1073741824) = -268435456 (overflow)

Legal ops: ! ~ & ^ | + << >>

Max ops: 12

Rating: 3

int threeFourths(int x) { }

For eleven I also need help with (no loops)

Puzzle Eleven bitCount - returns count of number of 1's in word

Examples: bitCount(5) = 2, bitCount(7) = 3

Legal ops: ! ~ & ^ | + << >>

Max ops: 40

Rating: 4

int bitCount(int x)

------------------------------------------what I thought of

{

int counter;

for(counter =0; value!=0; counter ++, value & = value-1);

return counter;

}