Syncboot/arch/i386/tty.c

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/************************
*** Team Kitty, 2019 ***
*** Sync ***
***********************/
/* This file provides all of the functionality
* needed to interact with the Text-Mode VGA
* buffer, which will soon be defunct due to
* EFI and graphics.
*
* This file will be left for the forseeable
* future, because it allows for easy debugging.
* 17/07/19 Curle
*/
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
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//#include <string.h>
#include "kernel/tty.h"
#include "kernel/utils.h"
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static const size_t TERM_WIDTH = 80;
static const size_t TERM_HEIGHT = 25;
static size_t terminal_row;
static size_t terminal_column;
static uint8_t current_color;
static uint16_t* term_buffer;
volatile uint16_t* vga_buffer = (uint16_t*)0xB8000;
void screen_initialize(void) {
terminal_row = 0;
terminal_column = 0;
current_color = vga_color_set(LIGHT_GREY, BLACK);
term_buffer = vga_buffer;
for (size_t y = 0; y < TERM_HEIGHT; y++) {
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for (size_t x = 0; x < TERM_WIDTH; x++) {
const size_t offset = y * TERM_WIDTH + x;
term_buffer[offset] = vga_entry(' ', current_color);
}
}
}
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void term_setcolor(enum vga_colors color) { current_color = color; }
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void term_putentryat(char c, uint8_t color, size_t x, size_t y) {
const size_t offset = y * TERM_WIDTH + x;
term_buffer[offset] = vga_entry(c, color);
}
void term_putchar(char c) {
unsigned char uc = c;
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// Handle escaped characters, such as newline, and crtn.
switch (uc) {
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case '\n':
terminal_column = 0;
terminal_row += 1;
break;
default:
term_putentryat(uc, current_color, terminal_column, terminal_row);
if (++terminal_column == TERM_WIDTH) {
terminal_column = 0;
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if (++terminal_row == TERM_HEIGHT) {
term_scroll(false);
terminal_row = 0;
}
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}
break;
}
}
struct csi_sequence parse_csi(const char* data, size_t size) {
enum State { PARAMETER, INTERMEDIATE, FINAL, INVALID };
enum State state = PARAMETER;
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struct csi_sequence sequence = {.parameter = NULL,
.parameter_len = 0,
.intermediate = NULL,
.intermediate_len = 0,
.final = NULL,
.valid = false};
for (size_t j = 0; j < size; j++) {
uint8_t c = data[j];
if (state == PARAMETER && (c >= 0x30 && c <= 0x3F)) {
if (!sequence.parameter)
sequence.parameter = data + j;
sequence.parameter_len++;
} else if (c >= 0x20 && c <= 0x2F) {
if (!sequence.intermediate)
sequence.intermediate = data + j;
sequence.intermediate_len++;
state = INTERMEDIATE;
} else if (c >= 0x40 && c <= 0x7F) {
sequence.final = data + j;
sequence.valid = true;
state = FINAL;
break;
} else {
// Parameter found in intermediate byte location, or byte out of
// range
state = INVALID;
break;
}
}
return sequence;
}
void term_write(const char* data, size_t size) {
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for (size_t i = 0; i < size; i++) {
// Begin handling ANSI escape codes.
if (data[i] == 0x1b) { // The current character is ESC - the start of ANSI codes.
// term_writes("ANSI Code encountered: ");
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bool string_terminated = false; // Flag used in some of the escape codes
// TODO: Should only progress if we have at least 2 more bytes
switch ((uint8_t)data[i + 1]) {
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case '[': // CSI - Control Sequence Introducer (The most common one, hence it comes first)
{
struct csi_sequence sequence = parse_csi(data + i + 2, size - (i + 2));
if (sequence.valid) {
// Send it off to our handler function to keep this part clean
handleControlSequence(sequence);
i += sequence.parameter_len + sequence.intermediate_len + 2; // Move past sequence
}
} break;
// Single shifts are not handled, so just print them and exit
case 'N': // SS2 - Single Shift Two
term_writes("Single Shift Two\n");
break;
case 'O': // SS3 - Single Shift Three
term_writes("Single Shift Three\n");
break;
// Control Strings
case 'P': // DCS - Device Control String
term_writes("Device Control String");
string_terminated = false;
break;
case '\\': // ST - String Terminator
term_writes("String Terminator\n");
string_terminated = true;
break;
case ']': // OSC - Operating System Command
term_writes("Operating System Command\n");
string_terminated = false;
break;
case 'X': // SOS - Start Of String
term_writes("Start of String");
string_terminated = false;
break;
case '^': // PM - Privacy Message
term_writes("Privacy Message\n");
break;
case '_': // APC - Application Program Command
term_writes("Application Program Command\n");
break;
}
} else {
term_putchar(data[i]);
}
}
}
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void term_writes(const char* data) { term_write(data, strlen(data)); }
void puts(const char* string) {
term_write(string, strlen(string));
term_putchar('\n');
}
void handleControlSequence(struct csi_sequence sequence) {
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// Check for our failsafes
if (sequence.valid) {
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int n = 0; // Default of the flag used for a few items
// Parse parameters, we only care about a max 2 of number only parameters
// for now
int params[2] = {0};
int param_count = 0;
if (sequence.parameter_len) {
for (size_t i = 0; i < sequence.parameter_len && param_count < 1; i++) {
char c = sequence.parameter[i];
if (isDigit(c)) {
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n = (n * 10) + (sequence.parameter[i] - '0');
} else if (c == ';') {
params[param_count++] = n;
}
}
params[param_count++] = n;
}
switch (*(sequence.final)) {
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case 'H':
case 'f': // CUP - Cursor Position
// TODO: Check to see if we have 2 paramaters
if (params[0])
params[0]--;
if (params[1])
params[1]--;
set_cursor(params[0], params[1]);
break;
case 'A': // CUU - Cursor Up
if (!params[0])
params[0] = 1;
set_cursor(terminal_column, terminal_row - params[0]);
break;
case 'B': // CUD - Cursor Down
if (!params[0])
params[0] = 1;
set_cursor(terminal_column, terminal_row + params[0]);
break;
case 'C': // CUF - Cursor Forward
if (!params[0])
params[0] = 1;
set_cursor(terminal_column + params[0], terminal_row);
break;
case 'D': // CUB - Cursor Back
if (!params[0])
params[0] = 1;
set_cursor(terminal_column - params[0], terminal_row);
break;
case 'E': // CNL - Cursor Next Line
if (!params[0])
params[0] = 1;
set_cursor(0, terminal_row + params[0]);
break;
case 'F': // CPL - Cursor Previous Line
if (!params[0])
params[0] = 1;
set_cursor(0, terminal_row - params[0]);
break;
case 'G': // CHA - Cursor Horizontal Absolute
if (params[0])
params[0]--;
set_cursor(params[0], terminal_row);
break;
case 'J': // ED - Erase in Display
{
// current cursor pos = y * width + x
int pos = terminal_row * 80 + terminal_column;
if (params[0] == 0) { // Clear from cursor to end of screen
for (; pos < (25 * 80); pos++) {
vga_buffer[pos] = '\0';
}
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} else if (params[0] == 1) { // Clear from cursor to beginning
for (; pos > 0; pos--) {
vga_buffer[pos] = '\0';
}
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} else if (params[0] == 2 || params[0] == 3) { // Clear entire screen
// TODO: Support scrollback buffer? (n = 3)
for (int i = 0; i < (25 * 80); i++) {
vga_buffer[0] = '\0';
}
}
break;
}
case 'K': // EL - Erase in Line
{
int pos = terminal_row * 80 + terminal_column;
if (params[0] == 0) { // From cursor to end of line
int endPos = (terminal_row + 1) * 80 - 1; // End of line = current row + 25 columns = current row + 1
for (; pos < endPos; pos++) {
vga_buffer[pos] = '\0';
}
} else if (params[0] == 1) { // From cursor to start of line
int endPos = terminal_row * 80; // Start of line = end of previous line + 1 == current line
for (; pos > endPos; pos--) {
vga_buffer[pos] = '\0';
}
} else if (params[0] == 2) { // Entire current line
pos = terminal_row * 80;
int endPos = (terminal_row + 1) * 80 - 1;
for (; pos < endPos; pos++) {
vga_buffer[pos] = '\0';
}
}
break;
}
case 'S': // SU - Scroll Up
term_scroll(true);
break;
case 'T': // SD - Scroll Down
term_scroll(false);
break;
}
}
}
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bool isDigit(char c) { return c >= '0' && c <= '9'; }
void set_cursor(int n, int m) {
terminal_column = n;
terminal_row = m;
}
void term_scroll(bool down) {
int current_pos;
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if (down) {
current_pos = 25 * 80; // Start of the last line.
} else {
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current_pos = 160; // Start of the second line.
}
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unsigned char* term_buffer = (unsigned char*)vga_buffer;
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if (down) { // To scroll down, move every character into the one below it, or "pull" every character down
while (current_pos > 80) {
term_buffer[current_pos + 160] = vga_buffer[current_pos];
term_buffer[current_pos + 159] = vga_buffer[current_pos - 1];
current_pos -= 2;
}
} else {
while (current_pos <= 4000) {
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term_buffer[current_pos - 160 /*The character immediately below it*/] =
vga_buffer[current_pos]; // Move each character up a line
term_buffer[current_pos - 159 /*The color of the character below*/] =
vga_buffer[current_pos + 1]; // As well as its color
current_pos += 2; // Move to next char
}
}
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if (down) {
current_pos = 0; // Start of first line
for (; current_pos < 80; current_pos++) {
term_buffer[current_pos] = '\0';
current_pos += 2;
}
} else {
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; // Start of the last line
// Wipe out the bottom line
for (current_pos = 3840; current_pos <= 3920; current_pos += 2) {
term_buffer[current_pos] = 0;
}
}
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terminal_row = 24; // Start writing on the last line
terminal_column = 0;
}