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Add IDT class for managing the interrupt table

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This commit is contained in:
Eryn Wells 2016-03-02 02:02:01 -05:00
parent d2cfbfd45d
commit 00e961435e
2 changed files with 142 additions and 15 deletions
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73
src/Descriptors.hh
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@ -9,24 +9,24 @@
namespace kernel {
void initGDT();
/**
* SegmentDescriptors are entries in the GDT and LDT that describe memory
* segments. Each descriptor is two double-words (8 bytes, 64 bits) long.
*/
typedef uint64_t Descriptor;
/** Descriptor privilege level. */
enum class DPL {
Ring0 = 0x0,
Ring1 = 0x1,
Ring2 = 0x2,
Ring3 = 0x3
};
struct GDT
{
/**
* SegmentDescriptors are entries in the GDT and LDT that describe memory
* segments. Each descriptor is two double-words (8 bytes, 64 bits) long.
*/
typedef uint64_t Descriptor;
/** Descriptor privilege level. */
enum class DPL {
Ring0 = 0x0,
Ring1 = 0x1,
Ring2 = 0x2,
Ring3 = 0x3
};
/** A four bit value describing the type of the segment. */
enum class Type {
// Data segment types
@ -93,4 +93,47 @@ private:
Descriptor table[Size];
};
struct IDT
{
enum class Type {
Task = 0x5,
Interrupt = 0x6,
Trap = 0x7,
};
struct DescriptorSpec
{
uint16_t segment;
uint32_t offset;
bool isPresent;
DPL privilegeLevel;
bool is32BitGate;
Type type;
Descriptor descriptor() const;
};
static IDT& systemIDT();
IDT();
/** Set the descriptor at the given `index` to the value of `spec`. */
void setDescriptor(size_t index, const DescriptorSpec& spec);
/** Set the descriptor at the given `index` to the NULL descriptor. */
void setNullDescriptor(size_t index);
void load() const;
private:
/**
* Size of the table. IDTs shouldn't have any more than this many
* descriptors.
*/
static const size_t Size = 256;
Descriptor mTable[Size];
};
} /* namespace kernel */