Left shift bits within 6 bits of a byte, wrapping at the end

main.cpp

#include <stdio.h>
#include <stdlib.h>

// shift bits to the left, while wrapping
// but only wrap within the 6 LSBs (ignore the 2 MSBs)

unsigned char shift_bit(unsigned char theByte);

int main(int argc, char **argv) {
    if (argc != 2) {
        printf("Usage: %s <byte>\n", argv[0]);
        return 1;
    }
    
    unsigned char bytee = atoi(argv[1]);

    char buffer[33];
    itoa(bytee, buffer, 2);
    printf("Byte before shifting: %s\n", buffer);

    bytee = shift_bit(bytee);

    itoa(bytee, buffer, 2);
    printf("Byte after shifting: %s\n", buffer);

    return 0;
}

// Function to shift a bit
unsigned char shift_bit(unsigned char theByte) {
    unsigned char bit;
    // bit = (theByte & 0x80) >> 7;  // Extract the leftmost bit
    bit = (theByte & 0x20) >> 5;  // Extract the leftmost bit (within the 6 LSBs)
    theByte = (theByte << 1) | bit;  // Shift left and OR with the extracted bit
    return theByte & 0x3F;  // Mask the 2 MSBs to 0
}