50 lines
957 B
C
50 lines
957 B
C
#ifndef GDT_H
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#define GDT_H
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#include <stdint.h>
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#define GDT_NB_ENTRIES 3
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#define GDT_SIZE (GDT_NB_ENTRIES * sizeof(struct gdt_entry))
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#define KERNEL_CS_INDEX 1
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#define KERNEL_DS_INDEX 2
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struct gdt_entry
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{
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uint16_t limit_1 : 16;
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uint16_t base_1 : 16;
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uint8_t base_2 : 8;
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uint8_t seg_type : 4;
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uint8_t desc_type : 1;
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uint8_t desc_priv : 2;
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uint8_t present : 1;
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uint8_t limit_2 : 4;
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uint8_t available : 1;
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uint8_t l : 1;
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uint8_t db : 1;
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uint8_t granularity : 1;
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uint8_t base_3 : 8;
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} __attribute__ ((packed));
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struct gdt
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{
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struct gdt_entry entries[GDT_NB_ENTRIES];
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};
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struct gdt_r
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{
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uint32_t addr;
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uint16_t limit;
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} __attribute__ ((packed));
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struct segment_selector
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{
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uint8_t rpl : 2;
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uint8_t table_indicator : 1;
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uint16_t index : 13;
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} __attribute__ ((packed));
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void init_gdt();
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#endif /* !GDT_H */
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