esp32-alarm-clock/main/bcd.c

/*
 * SPDX-FileCopyrightText: 2022 Helmut Pozimski <helmut@pozimski.eu>
 *
 * SPDX-License-Identifier: GPL-2.0-only
 */

#include <stdint.h>

uint8_t bcd_first_digit_value_bin(uint8_t bcd_value) {
    return (((bcd_value & 0xF0) >> 4)) * 10;
}

uint8_t bcd_last_digit_value_bin(uint8_t bcd_value) {
    return bcd_value & 0x0F;
}

uint8_t bcd2bin(uint8_t bcd_value) {
    return bcd_last_digit_value_bin(bcd_value) + bcd_first_digit_value_bin(bcd_value);
}

uint8_t bin2bcd(uint8_t bin_value) {
    uint8_t second_digit = (bin_value / 10) << 4;
    uint8_t first_digit = bin_value % 10;
    return first_digit + second_digit;
}