program.sh

#!/bin/bash

# Function to determine the sign of an integer
get_sign() {
    local num=$1
    # Shift the sign bit of the integer to the rightmost position
    local sign_bit=$((num >> 31))

    # Use the sign bit to determine the sign
    local sign=$((1 - ((sign_bit + sign_bit) & 1)))

    echo $sign
}

# Function to find the minimum of two integers using branchless approach
min_branchless() {
    local a=$1
    local b=$2

    # Calculate the difference between a and b
    local diff=$((a - b))

    # Calculate the sign bit of the difference
    local sign_bit=$((diff >> 31))

    # If a is less than b, the sign_bit will be -1 (1111...1111).
    # If a is greater than or equal to b, the sign_bit 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.
    local min_value=$((b + (diff & sign_bit)))

    echo $min_value
}

# Function to check if a is smaller than b
is_smaller() {
    local a=$1
    local b=$2

    # Check if a is smaller than b
    [ $((a - b)) -lt 0 ]
}

# Function to find the minimum of two integers using arithmetic
min_with_helper() {
    local a=$1
    local b=$2

    # Returns 1 if a < b, 0 otherwise
    local smaller=$(( (a - b) >> 31 & 1 ))

    # a + (b - a) * smaller: if smaller=1, returns b; if smaller=0, returns a
    echo $((a + (b - a) * smaller))
}

# Test the functions
num1=42
num2=-7
num3=0

echo "Sign of $num1: $(get_sign $num1)"
echo "Sign of $num2: $(get_sign $num2)"
echo "Sign of $num3: $(get_sign $num3)"

a=15
b=9

echo "Minimum of $a and $b (branchless): $(min_branchless $a $b)"
echo "Minimum of $a and $b (with helper): $(min_with_helper $a $b)"