program.c

#include <stdio.h>

// Function to determine the sign of an integer
int getSign(int num) {
    // Shift the sign bit of the integer to the rightmost position
    int signBit = num >> 31;

    // Use the sign bit to determine the sign:
    // If the number is positive, signBit will be 0 (0000...0000).
    // If the number is negative, signBit will be -1 (1111...1111).
    // If the number is zero, the signBit will remain 0.
    // We can then use the absolute value of signBit as the sign representation.
    int sign = 1 - ((signBit + signBit) & 1);

    return sign;
}

// Function to find the minimum of two integers using branchless approach
int minBranchless(int a, int b) {
    // Calculate the difference between a and b
    int diff = a - b;

    // Calculate the sign bit of the difference
    int signBit = diff >> 31;

    // If a is less than b, the signBit will be -1 (1111...1111).
    // If a is greater than or equal to b, the signBit will be 0 (0000...0000).
    // In the case where a is less than b, we will add the difference to b.
    // Otherwise, we will add 0 to b, effectively keeping b as the minimum.
    int minValue = b + (diff & signBit);

    return minValue;
}

// Function to check if a is smaller than b
int isSmaller(int a, int b) {
    // Check if a is smaller than b
    return (a - b) < 0;
}

// Function to find the minimum of two integers using a helper function
int minWithHelper(int a, int b) {
    // If isSmaller(a, b) returns true, then a is smaller than b.
    // In this case, we will return a + 0, effectively keeping a as the minimum.
    // Otherwise, if isSmaller(a, b) returns false, then a is greater than or equal to b.
    // In this case, we will return a + (b - a), which will be equal to b.
    // This effectively returns the smaller of the two values.
    return a + (b - a) * isSmaller(a, b);
}

int main() {
    int num1 = 42;
    int num2 = -7;
    int num3 = 0;

    printf("Sign of %d: %d\n", num1, getSign(num1));
    printf("Sign of %d: %d\n", num2, getSign(num2));
    printf("Sign of %d: %d\n", num3, getSign(num3));

    int a = 15;
    int b = 9;

    printf("Minimum of %d and %d (branchless): %d\n", a, b, minBranchless(a, b));
    printf("Minimum of %d and %d (with helper): %d\n", a, b, minWithHelper(a, b));

    return 0;
}