DOS/mouse.c at main · PythonCoders45/DOS · GitHub

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#include"types.h"

intmouse_x=512; // Start at center of 1024x768 screen
intmouse_y=384;
uint8_tmouse_bytes[3];
uint8_tmouse_cycle=0;

externvoiddraw_rect(intx, inty, intw, inth, uint32_tcolor);

/**
 * @brief Handles PS/2 Mouse Interrupt (IRQ 12)
 */
voidmouse_handler(uint8_tscancode) {
switch (mouse_cycle) {
case0:
mouse_bytes[0] =scancode;
mouse_cycle++;
break;
case1:
mouse_bytes[1] =scancode;
mouse_cycle++;
break;
case2:
mouse_bytes[2] =scancode;

// Calculate relative offset
intrel_x= (int8_t)mouse_bytes[1];
intrel_y= (int8_t)mouse_bytes[2];

mouse_x+=rel_x;
mouse_y-=rel_y; // Invert Y for screen space

// Clamp mouse inside screen bounds
if (mouse_x<0) mouse_x=0;
if (mouse_y<0) mouse_y=0;
if (mouse_x>1023) mouse_x=1023;
if (mouse_y>767) mouse_y=767;

mouse_cycle=0;
break;
 }
}

/**
 * @brief Draws a simple $5 \times 5$ square mouse cursor
 */
voiddraw_mouse_cursor(void) {
draw_rect(mouse_x, mouse_y, 5, 5, 0x00FF0000); // Red Cursor Pointer
}