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/** @file console.c
*
* @brief Console driver implementation.
*
* @author Hanjie Wu (hanjiew)
* @bug No functional bugs
*/
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include <x86/asm.h>
#include <x86/video_defines.h>
#include <console.h>
/** how many bits in a x86 byte */
#define NUM_OF_BITS_X86 8
/** Mask bits for a 8-bit byte */
#define BYTE_MASK_X86 0xFF
/** index of the register to start displaying cursor */
#define CRTC_CURSOR_START 10
/** bit to start displaying cursor */
#define CURSOR_ENABLE_BIT 0x20
/**
* Someone is not satisfied with the type name char_t so we use this
* to reperesent a char on screen so that nobody will mistake it with 'char'
*/
typedef struct a_char_on_screen_s {
uint8_t ch; /** char */
uint8_t color; /** color */
} a_char_on_screen_t;
/** pointer to the viedo memory at B800h */
a_char_on_screen_t (*console_mem)[CONSOLE_WIDTH] =
(a_char_on_screen_t(*)[CONSOLE_WIDTH])CONSOLE_MEM_BASE;
/** the char used to produce blank */
#define BLANK_CH ' '
/** initial color of the cursor */
#define DEFAULT_COLOR (FGND_WHITE | BGND_BLACK)
/** x position of the cursor */
static int cur_x = 0;
/** y position of the cursor */
static int cur_y = 0;
/** current color of the cursor */
static char cur_color = DEFAULT_COLOR;
/** should the cursor be displayed? */
static int cur_shown = true;
/** mutex for console operations */
mutex_t console_lock = MUTEX_INIT;
/**
* @brief Move the cursor to a position. Position is checked before calling this
* function
* @param x x
* @param y y
*/
static void move_cursor(int x, int y) {
cur_x = x;
cur_y = y;
int pos = y * CONSOLE_WIDTH + x;
outb(CRTC_IDX_REG, CRTC_CURSOR_LSB_IDX);
outb(CRTC_DATA_REG, pos & BYTE_MASK_X86);
outb(CRTC_IDX_REG, CRTC_CURSOR_MSB_IDX);
outb(CRTC_DATA_REG, pos >> NUM_OF_BITS_X86);
}
/**
* @brief Scroll the console by one line and clean the last line
*/
static void scroll_page() {
/* move all but last line forward */
memmove(console_mem[0], console_mem[1],
sizeof(a_char_on_screen_t) * CONSOLE_WIDTH * (CONSOLE_HEIGHT - 1));
int i;
for (i = 0; i < CONSOLE_WIDTH; i++) {
console_mem[CONSOLE_HEIGHT - 1][i] =
(a_char_on_screen_t){BLANK_CH, cur_color};
}
}
int putbyte(char ch) {
if (ch == '\n') {
if (cur_y < CONSOLE_HEIGHT - 1) {
move_cursor(0, cur_y + 1);
} else {
scroll_page();
move_cursor(0, cur_y);
}
return ch;
}
if (ch == '\r') {
move_cursor(0, cur_y);
return ch;
}
if (ch == '\b') {
if (cur_x > 0) {
move_cursor(cur_x - 1, cur_y);
} else if (cur_y > 0) {
move_cursor(CONSOLE_WIDTH - 1, cur_y - 1);
}
console_mem[cur_y][cur_x] = (a_char_on_screen_t){BLANK_CH, cur_color};
return ch;
}
/* save the position where we should show the char */
int prev_x = cur_x, prev_y = cur_y;
if (cur_x < CONSOLE_WIDTH - 1) {
/* move forward */
move_cursor(cur_x + 1, cur_y);
} else if (cur_y < CONSOLE_HEIGHT - 1) {
/* go to next line */
move_cursor(0, cur_y + 1);
} else {
/* scroll and go to beginning of the line */
scroll_page();
move_cursor(0, cur_y);
prev_y -= 1;
}
console_mem[prev_y][prev_x] = (a_char_on_screen_t){ch, cur_color};
return ch;
}
void putbytes(const char* s, int len) {
if (s == NULL || len <= 0) {
return;
}
int i;
for (i = 0; i < len; i++) {
putbyte(s[i]);
}
}
void draw_char(int row, int col, int ch, int color) {
if (row >= CONSOLE_HEIGHT || row < 0) {
return;
}
if (col >= CONSOLE_WIDTH || col < 0) {
return;
}
if (color > BYTE_MASK_X86 || color < 0) {
return;
}
console_mem[row][col] = (a_char_on_screen_t){ch, color};
}
int set_term_color(int color) {
if (color > BYTE_MASK_X86 || color < 0) {
return -1;
}
cur_color = (char)color;
return 0;
}
void get_term_color(int* color) {
*color = cur_color;
}
int set_cursor(int row, int col) {
if (row >= CONSOLE_HEIGHT || row < 0) {
return -1;
}
if (col >= CONSOLE_WIDTH || col < 0) {
return -1;
}
move_cursor(col, row);
return 0;
}
void get_cursor(int* row, int* col) {
*row = cur_y;
*col = cur_x;
}
void hide_cursor(void) {
cur_shown = 0;
outb(CRTC_IDX_REG, CRTC_CURSOR_START);
outb(CRTC_DATA_REG, inb(CRTC_DATA_REG) | CURSOR_ENABLE_BIT);
}
void show_cursor(void) {
cur_shown = 1;
outb(CRTC_IDX_REG, CRTC_CURSOR_START);
outb(CRTC_DATA_REG, inb(CRTC_DATA_REG) & ~CURSOR_ENABLE_BIT);
}
void clear_console(void) {
move_cursor(0, 0);
int i, j;
for (i = 0; i < CONSOLE_HEIGHT - 1; i++) {
for (j = 0; j < CONSOLE_WIDTH - 1; j++) {
console_mem[i][j] = (a_char_on_screen_t){BLANK_CH, cur_color};
}
}
}
char get_char(int row, int col) {
if (row >= CONSOLE_HEIGHT || row < 0) {
return BLANK_CH;
}
if (col >= CONSOLE_WIDTH || col < 0) {
return BLANK_CH;
}
return console_mem[row][col].ch;
}
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