[GPIO-Design] Undetermined behavior on `gpio_set(...)` API

[pavly-gerges]

Just navigating the content, and I am bit curious about this piece of code:
https://github.com/arm-university/Efficient-Embedded-Systems-Design-Education-Kit/blob/cadb6880c8a416f00c974cdb549781e04ea834c1/NUCLEO-F401RE/contents/Module07_GeneralPurposeDigitalInterfacing/Lab04_GeneralPurposeDigitalInterfacing/Code/GPIOBasicUI_lab/drivers/gpio.c#L22-L29

The problem will arise in case the user has inserted something else, other than the boolean zero or one. To disable the user from doing so, a preprocessing automaton must include a way to clamp the values to either zero or 1.

I did this trick before on my SDK, here:

void gpio_write(const gpio_port port, const uint8_t pin, uint8_t state) {
    *(port.DDRx) |= (1 << pin);
    /* Recall, PORTx = 0b01100000
       And, we want to change PINx4 to one
       Then, 1) Disable PORTxn first, through [(*(port.PORTx) & (~(1 << pin))].
             2) Add a state to PINxn, through [state << pin].
             3) Apply the PINxn_STATE to the PORT via [PORTxn_DISABLED | PINxn_STATE].
             4) Add the pin state to the PORT via [PORTxn_DISABLED | PINxn_STATE].
       So, PORTx = (0b01100000 & 0b11101111) | ((0b00010000) & (0b11111111)) 
                 = 0b01100000 | 0b00010000 = 0b01110000 */
    const volatile uint8_t PORTxn_DISABLED = (*(port.PORTx) & ~(1 << pin));
    const volatile uint8_t PINxn_STATE = (state && 0xFF) << pin; // this line here!
    *(port.PORTx) = PORTxn_DISABLED | PINxn_STATE;
} 

https://github.com/Electrostat-Lab/Electrostatic-Sandbox/blob/412fb970493d889992ae56ebfa0a3a4bebdbb12a/electrostatic-sandbox-framework/electrostatic-core/src/libs/electrostatic-primer/electroio/electromio/avr/libgpio/gpio_write.c#L3-L16

Just convert the value to logical value by ANDing it with 1. Or else use boolean data type for the pin value.