Challenge of handmade OS
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#include <Library/BaseLib.h>
#include "io.h"
#include "keycode.h"
#include "text.h"
#define SPECIAL_SHIFT_L 0b00000001
#define SPECIAL_SHIFT_R 0b00000010
#define SPECIAL_CTRL_L 0b00000100
#define SPECIAL_CTRL_R 0b00001000
#define SPECIAL_ALT_L 0b00010000
#define SPECIAL_ALT_R 0b00100000
#define SPECIAL_SUPER_L 0b01000000
#define SPECIAL_SUPER_R 0b10000000
void null_handler();
void kbd_handler();
IA32_IDT_GATE_DESCRIPTOR descriptors[256];
void descriptor_init() {
for (int i = 0; i < 256; i++) {
descriptors[i].Bits.Selector = 0x08;
descriptors[i].Bits.GateType = IA32_IDT_GATE_TYPE_INTERRUPT_32;
descriptors[i].Bits.OffsetLow = (UINT32)(UINTN)(VOID *)null_handler;
descriptors[i].Bits.OffsetHigh =
(UINT32)((UINTN)(VOID *)null_handler >> 16);
descriptors[i].Bits.OffsetUpper =
(UINT32)((UINTN)(VOID *)null_handler >> 32);
} // null descriptor set
}
void set_handler(int num, UINTN handler) {
descriptors[num].Bits.OffsetLow = (UINT32)handler;
descriptors[num].Bits.OffsetHigh = (UINT32)(handler >> 16);
descriptors[num].Bits.OffsetUpper = (UINT32)(handler >> 32);
}
void master_pic_init() {
mapped_io_write(0x0020, 0x11); // ICW1
mapped_io_write(0x0021, 32); // ICW2
mapped_io_write(0x0021, 0x04); // ICW3
mapped_io_write(0x0021, 0x01); // ICW4
mapped_io_write(0x0021, 0xFF); // OCW1
}
void slave_pic_init() {
mapped_io_write(0x00A0, 0x11);
mapped_io_write(0x00A1, 40);
mapped_io_write(0x00A1, 0x02);
mapped_io_write(0x00A1, 0x01);
mapped_io_write(0x00A1, 0xff);
}
void unmask_interrupt(UINT8 interrupt_num) {
if (interrupt_num < 40) {
UINT8 mask = mapped_io_read(0x0021);
mapped_io_write(0x0021, mask & ~(1 << (interrupt_num - 32)));
} else {
UINT8 mask = mapped_io_read(0x00A1);
mapped_io_write(0x00A1, mask & ~(1 << (interrupt_num - 40)));
}
}
void end_of_interrupt(UINT8 interrupt_num) {
if (interrupt_num < 40) {
mapped_io_write(0x0020, 0x60 | (interrupt_num - 32));
} else {
mapped_io_write(0x00A0, 0x60 | (interrupt_num - 40));
}
}
void interrupt_init() {
IA32_DESCRIPTOR Descriptor;
descriptor_init();
set_handler(33, (UINTN)(VOID *)kbd_handler);
Descriptor.Limit = (UINT16)(sizeof(descriptors) - 1);
Descriptor.Base = (UINT32)(UINTN)(VOID *)descriptors;
AsmWriteIdtr(&Descriptor);
EnableInterrupts();
master_pic_init();
slave_pic_init();
unmask_interrupt(33);
}
void keyboard_int_proc() {
UINT8 data;
static BOOLEAN special_flag = FALSE;
static char keyboard_special_keys = 0;
data = mapped_io_read(0x64);
if ((data & 0b00000001) == 0) // output buffer is not full
goto eoi;
data = mapped_io_read(0x60);
if (data == 0xE0) {
special_flag = TRUE;
goto eoi;
}
if (data & 0b10000000) { // key is broken
switch (data & 0b01111111) {
case 0x2A:
keyboard_special_keys &= ~SPECIAL_SHIFT_L;
goto eoi;
case 0x36:
keyboard_special_keys &= ~SPECIAL_SHIFT_R;
goto eoi;
case 0x1D:
if (!special_flag)
keyboard_special_keys &= ~SPECIAL_CTRL_L;
else
keyboard_special_keys &= ~SPECIAL_CTRL_R;
goto eoi;
case 0x38:
if (!special_flag)
keyboard_special_keys &= ~SPECIAL_ALT_L;
else
keyboard_special_keys &= ~SPECIAL_ALT_R;
goto eoi;
case 0x5B:
if (special_flag) keyboard_special_keys &= ~SPECIAL_SUPER_L;
goto eoi;
case 0x5C:
if (special_flag) keyboard_special_keys &= ~SPECIAL_SUPER_L;
goto eoi;
}
} else { // key is make
switch (data & 0b01111111) {
case 0x2A:
keyboard_special_keys |= SPECIAL_SHIFT_L;
goto eoi;
case 0x36:
keyboard_special_keys |= SPECIAL_SHIFT_R;
goto eoi;
case 0x1D:
if (!special_flag)
keyboard_special_keys |= SPECIAL_CTRL_L;
else
keyboard_special_keys |= SPECIAL_CTRL_R;
goto eoi;
case 0x38:
if (!special_flag)
keyboard_special_keys |= SPECIAL_ALT_L;
else
keyboard_special_keys |= SPECIAL_ALT_R;
goto eoi;
case 0x5B:
if (special_flag) keyboard_special_keys |= SPECIAL_SUPER_L;
goto eoi;
case 0x5C:
if (special_flag) keyboard_special_keys |= SPECIAL_SUPER_L;
goto eoi;
default:
if ((keyboard_special_keys & SPECIAL_SHIFT_L) ||
(keyboard_special_keys & SPECIAL_SHIFT_R)) {
if (keycode_to_ascii_shift[data])
textout(keycode_to_ascii_shift[data]);
} else if (keycode_to_ascii[data])
textout(keycode_to_ascii[data]);
goto eoi;
}
}
eoi:
end_of_interrupt(33);
}