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Kernel: Add terminal scrolling

This commit is contained in:
g1n 2021-09-12 12:16:47 +03:00
parent fc18048e2f
commit 7b912d6abe
1 changed files with 43 additions and 13 deletions
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56
kernel/arch/i386/tty.c
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@ -6,6 +6,7 @@
#include <kernel/tty.h> #include <kernel/tty.h>
#include "vga.h" #include "vga.h"
#include "../../kernel/asm_helper.h" // FIXME
static const size_t VGA_WIDTH = 80; static const size_t VGA_WIDTH = 80;
static const size_t VGA_HEIGHT = 25; static const size_t VGA_HEIGHT = 25;
@ -38,14 +39,42 @@ void terminal_putentryat(unsigned char c, uint8_t color, size_t x, size_t y) {
terminal_buffer[index] = vga_entry(c, color); terminal_buffer[index] = vga_entry(c, color);
} }
// Updates the hardware cursor.
static void move_cursor()
{
// The screen is 80 characters wide...
uint16_t cursorLocation = terminal_row * 80 + terminal_column;
outb(0x3D4, 14); // Tell the VGA board we are setting the high cursor byte.
outb(0x3D5, cursorLocation >> 8); // Send the high cursor byte.
outb(0x3D4, 15); // Tell the VGA board we are setting the low cursor byte.
outb(0x3D5, cursorLocation); // Send the low cursor byte.
}
void terminal_scroll(int line) { void terminal_scroll(int line) {
int loop; // Get a space character with the default colour attributes.
int c; int attributeByte = (0 /*black*/ << 4) | (15 /*white*/ & 0x0F);
uint16_t blank = 0x20 /* space */ | (attributeByte << 8);
for(loop = line * (VGA_WIDTH * 2) + 0xB8000; loop < VGA_WIDTH * 2; loop++) {
c = loop; // Row 25 is the end, this means we need to scroll up
//*(loop - (VGA_WIDTH * 2)) = c; if(terminal_row >= 25)
} {
// Move the current text chunk that makes up the screen
// back in the buffer by a line
int i;
for (i = 0*80; i < 24*80; i++)
{
terminal_buffer[i] = terminal_buffer[i+80];
}
// The last line should now be blank. Do this by writing
// 80 spaces to it.
for (i = 24*80; i < 25*80; i++)
{
terminal_buffer[i] = blank;
}
// The cursor should now be on the last line.
terminal_row = 24;
}
} }
@ -65,18 +94,19 @@ void terminal_putchar(char c) {
if (++terminal_column == VGA_WIDTH) { if (++terminal_column == VGA_WIDTH) {
terminal_column = 0; terminal_column = 0;
if (++terminal_row == VGA_HEIGHT) { if (++terminal_row == VGA_HEIGHT) {
for(int line = 1; line <= VGA_HEIGHT - 1; line++) for(int line = 1; line <= VGA_HEIGHT - 1; line++) {
{ terminal_scroll(line);
terminal_scroll(line); }
} terminal_delete_last_line();
terminal_delete_last_line(); terminal_row = VGA_HEIGHT - 1;
terminal_row = VGA_HEIGHT - 1;
} }
} }
} else { } else {
terminal_row += 1; terminal_row += 1;
terminal_column = 0; terminal_column = 0;
} }
terminal_scroll(terminal_row);
move_cursor();
} }
void terminal_write(const char* data, size_t size) { void terminal_write(const char* data, size_t size) {