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#ifndef MELVIX_SYSTEM_H
#define MELVIX_SYSTEM_H
/**
* Initialize the basic features of the OS
*/
void init();
/**
* The ASM registers as packed structure
*/
typedef struct __attribute__ ((packed)) {
unsigned short di, si, bp, sp, bx, dx, cx, ax;
unsigned short gs, fs, es, ds, eflags;
} regs16_t;
/**
* Execute BIOS interrupts by switching to real mode
* @param intnum The interrupt number (e.g. 0x10)
* @param regs The ASM registers
*/
extern void int32(unsigned char intnum, regs16_t *regs);
/**
* ASM segment:offset pointer
*/
struct far_ptr {
union {
uint32_t ptr;
struct {
uint16_t offset, segment;
};
};
} __attribute__ ((packed));
/**
* Get offset from ASM segment:offset pointer
*/
static inline uint16_t get_offset(const volatile void *p) {
return (uint16_t) (uintptr_t) p & 0x000F;
}
/**
* Get segment from ASM segment:offset pointer
*/
static inline uint16_t get_segment(const volatile void *p) {
return (uint16_t) (((uintptr_t) p) >> 4);
}
/**
* Convert pointer to far_ptr
* @param __ptr The ASM segment:offset pointer
* @return The new far pointer
*/
static inline struct far_ptr FAR_PTR(void *__ptr) {
struct far_ptr __fptr;
__fptr.offset = get_offset(__ptr);
__fptr.segment = get_segment(__ptr);
return __fptr;
}
/**
* Get pointer from ASM segment:offset far pointer
* @param fptr The ASM far pointer
* @return The normalized pointer
*/
static inline void *get_ptr(struct far_ptr fptr) {
return (void *) (unsigned long) ((fptr.segment << 4) + fptr.offset);
}
#endif
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