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40 lines
1011 B
40 lines
1011 B
#ifndef IDT_H
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#define IDT_H
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#include "types.h"
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/* Segment selectors */
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#define KERNEL_CS 0x08
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/* How every interrupt gate (handler) is defined */
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typedef struct {
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u16 low_offset; /* Lower 16 bits of handler function address */
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u16 sel; /* Kernel segment selector */
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u8 always0;
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/* First byte
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* Bit 7: "Interrupt is present"
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* Bits 6-5: Privilege level of caller (0=kernel..3=user)
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* Bit 4: Set to 0 for interrupt gates
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* Bits 3-0: bits 1110 = decimal 14 = "32 bit interrupt gate" */
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u8 flags;
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u16 high_offset; /* Higher 16 bits of handler function address */
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} __attribute__((packed)) idt_gate_t ;
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/* A pointer to the array of interrupt handlers.
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* Assembly instruction 'lidt' will read it */
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typedef struct {
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u16 limit;
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u32 base;
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} __attribute__((packed)) idt_register_t;
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#define IDT_ENTRIES 256
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idt_gate_t idt[IDT_ENTRIES];
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idt_register_t idt_reg;
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/* Functions implemented in idt.c */
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void set_idt_gate(int n, u32 handler);
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void set_idt();
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#endif
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