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/*
Low level VGA based console driver
*/
#include "string.h"
#include "video/vga.h"
#include "asm/io.h"
#define LIGHT_GREY_ON_BLACK \
VGA_ENTRY_COLOR(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK)
static uint16_t *vga_vram_base;
static size_t vga_vram_size;
static size_t vga_cols;
static size_t vga_rows;
static uint8_t vga_attr;
static size_t cursor_x;
static size_t cursor_y;
void vgacon_init(void)
{
vga_vram_base = (uint16_t *) VGA_VRAM_BC;
vga_cols = 80;
vga_rows = 25;
vga_vram_size = vga_cols * vga_rows;
vga_attr = LIGHT_GREY_ON_BLACK;
cursor_x = 0;
cursor_y = 0;
}
void vgacon_setattr(uint8_t attr)
{
vga_attr = attr;
}
void vgacon_scroll(size_t lines)
{
uint16_t vga_char = VGA_ENTRY(' ', vga_attr);
size_t count = (vga_rows - lines) * vga_cols;
memmove(vga_vram_base, vga_vram_base + vga_cols * lines, count * 2);
for(; count < vga_vram_size; count++)
vga_vram_base[count] = vga_char;
}
void vgacon_cls(void)
{
vgacon_scroll(vga_rows);
}
static void putchar(char c)
{
if(c == '\n') {
cursor_x = 0;
if(++cursor_y >= vga_rows) {
vgacon_scroll(1);
cursor_y--;
}
}
else {
const size_t index = cursor_y * vga_cols + cursor_x;
vga_vram_base[index] = VGA_ENTRY(c, vga_attr);
if(++cursor_x >= vga_cols) {
cursor_x = 0;
if(++cursor_y >= vga_rows) {
vgacon_scroll(1);
cursor_y--;
}
}
}
}
static void update_cursor()
{
uint16_t pos = cursor_y * vga_cols + cursor_x;
outb(VGA_CRTC_IC, VGA_CRTC_CURSOR_H);
outb(VGA_CRTC_DC, (uint8_t) ((pos >> 8) & 0xFF));
outb(VGA_CRTC_IC, VGA_CRTC_CURSOR_L);
outb(VGA_CRTC_DC, (uint8_t) (pos & 0xFF));
}
void vgacon_putchar(char c)
{
putchar(c);
update_cursor();
}
void vgacon_write(const char *str, size_t size)
{
size_t i;
for(i = 0; i < size; i++)
putchar(str[i]);
update_cursor();
}
void vgacon_print(const char *str)
{
vgacon_write(str, strlen(str));
}
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