/**
 * @file idt.h
 * @brief Interrupt Descriptor Table
 * @author Jake "lordtet" Holtham
 * @date 2025
 * IDT related structures, globals and functions
 */
#ifndef IDT_H
#define IDT_H

#include <stdint.h>

/**
 * @brief IDT Entry
 */
typedef struct InterruptDescriptor_s {
    uint16_t offset_lo;     /**< Lower 16 bits of ISR ptr  */
    uint16_t selector;      /**<  */
    uint8_t reserved;       /**< Nothing */
    uint8_t attributes;     /**< */
    uint16_t offset_hi;     /**< Upper 16 bits of ISR ptr  */
} InterruptDescriptor_t;

/**
 * @brief 
 */
typedef struct IDTR_s {
    uint16_t size;                      /**< IDT Length */
    InterruptDescriptor_t* IDT;         /**< Pointer to the IDT Entry array */
} __attribute__((packed)) IDTR_t;

/**
 * @brief The IDTR in memory. 
 */
extern IDTR_t idtr;

/**
 * @brief First IDT Entry
 */
extern InterruptDescriptor_t idt_start;

/**
 * @brief Amount of ISRs implemented
 */
extern unsigned char num_interrupts;

/**
 * @brief Call setup and write to construct and load the IDT.
 */
void setup_idt();

/**
 * @brief Write the IDT and IDTR 
 */
void write_descriptors();

/**
 * @brief LIDT call 
 */
extern void load_idt();

#endif