58 lines
1.4 KiB
C++
58 lines
1.4 KiB
C++
#include "gdt.hpp"
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#include "../Helpers/types.hpp"
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#include "../Helpers/memory.hpp"
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//Constructor
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Gdt::Gdt(){
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//Init conventional segment
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this->initGdtDesc(0x0,0x0,0x0,0x0, &m_Descriptors[0]);
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//Init code segment
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this->initGdtDesc(0x0,0xFFFFF,0x9A,0x0D, &m_Descriptors[1]);
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//Init data segment
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this->initGdtDesc(0x0,0xFFFFF,0x92,0x0D, &m_Descriptors[2]);
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//Init stack segment
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this->initGdtDesc(0x00B00000,0x00000500,0x96,0x0D, &m_Descriptors[3]);
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//Init GDT Pointer
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this->m_Pointer.size=4*sizeof(this->m_Descriptors);
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this->m_Pointer.segment=0x00007E00;
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}
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//Destructor
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Gdt::~Gdt(){
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}
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//Adapt parameter to the gdt descriptor structure
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void Gdt::initGdtDesc(u32 base, u32 limit, u8 access, u8 flags, gdtDescriptorStruct *Descriptor){
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Descriptor->limit1 = limit & 0xFFFF;
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Descriptor->base1 = base & 0xFFFF;
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Descriptor->base2 = (base & 0xFF0000) >> 16;
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Descriptor->access = access;
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Descriptor->limit2 = (limit & 0xF0000 ) >> 16;
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Descriptor->flags = flags & 0xFF;
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Descriptor->base3 = (base & 0xFF000000) >> 24;
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}
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//Copy the gdt into mémory and load it
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void Gdt::loadGdt(){
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//Copy Gdt into memory and init registers
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memcpy((u32)m_Descriptors, (u32)m_Pointer.segment, (u32)m_Pointer.size);
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//Put m_Pointer in a var to pass it to assembly code
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int *gdtAdress=(int *)&m_Pointer;
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__asm__("lgdtl (%0);"
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:
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:"r"(gdtAdress)
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);
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}
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