Ps/2 Compatible Mouse Driver May 2026

if (mouse_cycle == 0) // Byte 0: verify bit 3 = 1 (always set in standard packet) if ((data & 0x08) == 0x08) mouse_packet[0] = data; mouse_cycle = 1; else if (mouse_cycle == 1) mouse_packet[1] = data; mouse_cycle = 2; else if (mouse_cycle == 2) mouse_packet[2] = data; mouse_cycle = 0; // Decode movement int dx = (int)mouse_packet[1]; int dy = (int)mouse_packet[2]; // 9-bit sign extension if overflow bits are set if (mouse_packet[0] & 0x10) dx

int old_buttons = 0; while (1) Enabling Scroll Wheel (IntelliMouse) Send this sequence to switch to 4-byte packets: ps/2 compatible mouse driver

uint8_t data = inb(0x60);

void install_mouse_handler() set_idt_gate(0x2C, (uint32_t)mouse_isr, 0x08, 0x8E); outb(0x21, inb(0x21) & ~0x20); // Unmask IRQ12 on slave PIC outb(0xA1, inb(0xA1) & ~0x20); if (mouse_cycle == 0) // Byte 0: verify