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#include<stdbool.h>
#include<stddef.h>
#include<stdint.h>
#include"vga.h"
static const size_t VGA_WIDTH = 80;
static const size_t VGA_HEIGHT = 25;
#define PIC1_COMMAND_PORT 0x20
#define PIC1_DATA_PORT 0x21
#define PIC2_COMMAND_PORT 0xA0
#define PIC2_DATA_PORT 0xA1
// IO Ports for Keyboard
#define KEYBOARD_DATA_PORT 0x60
#define KEYBOARD_STATUS_PORT 0x64
extern char ioport_in(uint8_t port);
extern void ioport_out(uint8_t port, char data);
static inline uint8_t vga_entry_color(enum vga_color fg, enum vga_color bg)
{
return fg | bg << 4;
}
static inline uint16_t vga_entry(unsigned char uc, uint8_t color)
{
return (uint16_t) uc | (uint16_t) color << 8;
}
size_t terminal_row;
size_t terminal_column;
uint8_t terminal_color;
uint16_t* terminal_buffer;
void terminal_initialize(void)
{
terminal_row=0;
terminal_column=0;
terminal_color=vga_entry_color(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK);
terminal_buffer=(uint16_t*) 0xB8000;
for(size_t y=0;y<VGA_HEIGHT;y++)
{
for(size_t x=0;x<VGA_WIDTH;x++)
{
const size_t index=y*VGA_WIDTH+x;
terminal_buffer[index]=vga_entry(' ', terminal_color);
}
}
}
void terminal_putentryat(char c, uint8_t color, size_t x, size_t y)
{
const size_t index=y*VGA_WIDTH+x;
terminal_buffer[index]=vga_entry(c, color);
}
void movescreen()
{
terminal_row--;
for(size_t i=0;i<VGA_HEIGHT;i++) for(size_t j=0;j<VGA_WIDTH;j++) terminal_buffer[i*VGA_WIDTH+j]=terminal_buffer[(i+1)*VGA_WIDTH+j];
}
void terminal_putchar(char c)
{
if(c=='\n') terminal_column = 0,terminal_row++;
else
{
terminal_putentryat(c, terminal_color, terminal_column, terminal_row);
if (++terminal_column==VGA_WIDTH) terminal_column=0,terminal_row++;
}
if (terminal_row==VGA_HEIGHT) movescreen();
}
void terminal_writestring(const char* data)
{
for(int i=0;data[i]!='\0';i++) terminal_putchar(data[i]);
}
void init_keyboard()
{
// 0xFD = 1111 1101 in binary. enables only IRQ1
// Why IRQ1? Remember, IRQ0 exists, it's 0-based
ioport_out(PIC1_DATA_PORT, 0xFD);
}
#include"keyboard.h"
void handle_keyboard_interrupt()
{
// Write end of interrupt (EOI)
ioport_out(PIC1_COMMAND_PORT, 0x20);
unsigned char status = ioport_in(KEYBOARD_STATUS_PORT);
// Lowest bit of status will be set if buffer not empty
// (thanks mkeykernel)
if (status & 0x1)
{
char keycode = ioport_in(KEYBOARD_DATA_PORT);
if (keycode < 0 || (uint8_t)keycode >= 128) return;
if(keycode==14)
{
if(terminal_column) terminal_column--;
terminal_putchar(keyboard[keycode]);
terminal_column--;
return;
}
terminal_putchar(keyboard[keycode]);
}
}
void print_message()
{
for(size_t i=0;i<50;i++)
{
for(size_t j=0;j<i;j++) terminal_writestring("#");
terminal_writestring("Hello, kernel World!\n");
}
}
void kernel_main(void)
{
terminal_initialize();
print_message();
init_idt_table();
init_keyboard();
terminal_writestring("First part is working\n");
while(1);
}
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