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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;
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 kernel_main(void)
{
terminal_initialize();
for(size_t i=0;i<50;i++)
{
for(size_t j=0;j<i;j++) terminal_writestring("#");
terminal_writestring("Hello, kernel World!\n");
}
}
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