Bit Operations — set clear toggle

// Macros (Linux kernel style)
#define BIT(n)       (1u << (n))
#define GENMASK(h,l) (((1u << ((h)-(l)+1))-1) << (l))

val |=  (1u << n);           // SET bit n
val &= ~(1u << n);           // CLEAR bit n
val ^=  (1u << n);           // TOGGLE bit n

// SET bits 3–7 to 'mode' — raw, no macros
val = (val & ~(0x1Fu << 3)) | ((mode & 0x1Fu) << 3);
//    step 1: build mask → shift to pos 3 → negate → AND (clears bits 3-7)
//    step 2: shift mode to pos 3 → OR (writes new value)

// READ bits 3–7
uint32_t m = (*reg >> 3) & 0x1F;

⚠️ Always clear first, then set. |= alone cannot zero bits already set to 1.