idt.c

用于汇编领域的,运用于OS的MAIN函数.基于硬件基础的源代码

#include "hos.h"

static idt_selector_t __idt[IDT_ENTRIES];
static idtr_t __idtr;

void idt_traps_setup(void);

void do_divide_error(void);

void init_idt(void)
{
	unsigned long idt_base_addr = (unsigned long) __idt;

	/* setup idt entry */
	/* ... */
	idt_traps_setup();
	
	__idtr.limit = 8 * IDT_ENTRIES;
	__idtr.base = idt_base_addr;

	__asm__ __volatile__ (
		"lidt %0"
		:
		: "m" (__idtr)
	);
}


/* These codes from linux-2.4.20 */
#define _set_gate(gate_addr, type, dpl, addr) \
do { \
	int __d0, __d1; \
	__asm__ __volatile__ ( \
		"movw	%%dx, %%ax \n\t"\
		"movw	%4, %%dx \n\t" \
		"movl	%%eax, %0 \n\t" \
		"movl	%%edx, %1"\
		:"=m" (*((long *) (gate_addr))), \
		 "=m" (*(1+(long *) (gate_addr))), "=&a" (__d0), "=&d" (__d1) \
		:"i" ((short) (0x8000 + (dpl << 13) + (type << 8))), \
		 "3" ((char *) (addr)), "2" (0x08 << 16)); \
} while (0)

void set_intr_gate(unsigned int n, void *addr)
{
	_set_gate(__idt + n, 14, 0, addr);
}

static void set_trap_gate(unsigned int n, void *addr)
{
	_set_gate(__idt + n, 15, 0, addr);
}

static void set_system_gate(unsigned int n, void *addr)
{
	_set_gate(__idt + n, 15, 3, addr);
}

/* setting up trap & system call gate */
void idt_traps_setup(void)
{
	set_trap_gate(0, &divide_error);
/*
	set_trap_gate(1, &debug);
	set_trap_gate(2, &nmi);
	set_system_gate(3, &int3);
	set_system_gate(4, &overflow);
	set_system_gate(5, &bounds);
	set_trap_gate(6, &invalid_op);
	set_trap_gate(7, &device_not_available);
	set_trap_gate(8, &double_fault);
*/
}

void do_divide_error(void)
{
	printk("[kernel trap]: divide_error\n");
	STOP();
}