kernel/arch/x86/tty/tty.c

   1 #include <io.h>
   2 #include <tty.h>
   3 #include <stdint.h>
   4
   5 #define VGA_WIDTH 80
   6 #define VGA_HEIGHT 25
   7
   8 volatile char *video_memory = (char *) 0xB8000; /* VGA VRAM starts at 0xB8000 */
   9
  10 static int cursor_x = 0; /* keep track of where cursor is */
  11 static int cursor_y = 0;
  12
  13 char *hex_chars = "0123456789ABCDEF";
  14
  15 void screen_clear(void)
  16 {
  17         int x, y;
  18         for ( y = 0; y < VGA_HEIGHT; y++ ) {
  19                 for ( x = 0; x < VGA_WIDTH; x++ ) {
  20                         video_memory[(y * VGA_WIDTH + x) * 2 + 1] = VGA_COLOR_LIGHT_GRAY;
  21                         video_memory[(y * VGA_WIDTH + x) * 2] = ' ';
  22                 }
  23         }
  24
  25         cursor_x = 0;
  26         cursor_y = 0;
  27 }
  28
  29 void scroll_up(void)
  30 {
  31         int x, y;
  32         for ( y = 1; y < VGA_HEIGHT; y++ ) {
  33                 for ( x = 0; x < VGA_WIDTH; x++ ) {
  34                         video_memory[((y - 1) * VGA_WIDTH + x) * 2] = video_memory[(y * VGA_WIDTH + x) * 2];
  35                 }
  36         }
  37         for ( x = 0; x < VGA_WIDTH; x++ ) {
  38                 video_memory[((VGA_HEIGHT - 1) * VGA_WIDTH + x) * 2] = ' ';
  39         }
  40         cursor_y = VGA_HEIGHT - 1;
  41 }
  42
  43 void kprint(const char *string, uint8_t color)
  44 {
  45         char next_char;
  46         uint8_t vga_misc_output;
  47         uint16_t crtc_port;
  48         next_char = *string;
  49
  50         while ( next_char != 0 ) {
  51                 if ( next_char == '\n') { cursor_x = 0; cursor_y++; }
  52                 else { video_memory[(cursor_y * VGA_WIDTH + cursor_x) * 2] = next_char; video_memory[((cursor_y * VGA_WIDTH + cursor_x++) * 2)+ 1] = color != 0 ? color : VGA_COLOR_LIGHT_GRAY; }
  53                 if ( cursor_x >= VGA_WIDTH ) { cursor_x = 0; cursor_y++; }
  54                 if ( cursor_y >= VGA_HEIGHT ) { scroll_up(); }
  55                 next_char = *++string;
  56         }
  57
  58         vga_misc_output = inb(0x3CC);
  59         if (vga_misc_output & 0x1 == 0) {
  60                 crtc_port = 0x3B4;
  61         } else {
  62                 crtc_port = 0x3D4;
  63         }
  64
  65         outb(crtc_port, 0xE);
  66         outb(crtc_port + 1, (cursor_y * VGA_WIDTH + cursor_x) >> 8);
  67         outb(crtc_port, 0xF);
  68         outb(crtc_port + 1, (cursor_y * VGA_WIDTH + cursor_x) & 0xFF);
  69 }
  70
  71 void kprintc(const char character, uint8_t color)
  72 {
  73         uint8_t vga_misc_output;
  74         uint16_t crtc_port;
  75
  76         if ( character == '\n') { cursor_x = 0; cursor_y++; }
  77         else { video_memory[(cursor_y * VGA_WIDTH + cursor_x) * 2] = character; video_memory[((cursor_y * VGA_WIDTH + cursor_x++) * 2)+ 1] = color != 0 ? color : VGA_COLOR_LIGHT_GRAY; }
  78         if ( cursor_x >= VGA_WIDTH ) { cursor_x = 0; cursor_y++; }
  79         if ( cursor_y >= VGA_HEIGHT ) { scroll_up(); }
  80
  81         vga_misc_output = inb(0x3CC);
  82         if (vga_misc_output & 0x1 == 0) {
  83                 crtc_port = 0x3B4;
  84         } else {
  85                 crtc_port = 0x3D4;
  86         }
  87
  88         outb(crtc_port, 0xE);
  89         outb(crtc_port + 1, (cursor_y * VGA_WIDTH + cursor_x) >> 8);
  90         outb(crtc_port, 0xF);
  91         outb(crtc_port + 1, (cursor_y * VGA_WIDTH + cursor_x) & 0xFF);
  92
  93 }
  94
  95 void kprintnibble(uint8_t nibble)
  96 {
  97         nibble &= 0xf;
  98         if (nibble < 0xa)
  99                 kprintc('0' + nibble, 0);
 100         else kprintc('a' - 0xa + nibble, 0);
 101 }
 102
 103 void kprintb(uint8_t byte, int print_delm)
 104 {
 105         if (print_delm)
 106                 kprint("0x", 0);
 107
 108         kprintnibble(byte >> 4);
 109         kprintnibble(byte);
 110 }
 111
 112 void kprintw(uint16_t word, int print_delm)
 113 {
 114         if (print_delm)
 115                 kprint("0x", 0);
 116
 117         kprintb(word >> 8, 0);
 118         kprintb(word, 0);
 119 }
 120
 121 void kprintd(uint32_t dword, int print_delm)
 122 {
 123         if (print_delm)
 124                 kprint("0x", 0);
 125
 126         kprintw(dword >> 16, 0);
 127         kprintw(dword, 0);
 128 }
 129
 130 void kprintq(uint64_t qword, int print_delm)
 131 {
 132         if (print_delm)
 133                 kprint("0x", 0);
 134
 135         kprintd(qword >> 32, 0);
 136         kprintd(qword, 0);
 137 }
 138
 139 int kprintdec(uint32_t num, uint8_t color)
 140 {
 141         char buffer[11];
 142         int digits = 10;
 143         /* TODO: make an actual memset function to use instead of this */
 144         for (int i=0; i<11; i++) {
 145                 buffer[i] = 0;
 146         }
 147
 148         /* put the numbers in the buffer */
 149         for (int i=9; i>0 && num>0; i--) {
 150                 uint8_t currdigit = num%10;
 151                 buffer[i] = currdigit+'0';
 152                 num /= 10;
 153         }
 154
 155         /* shift the array as much as needed */
 156         while (*buffer == '\0') {
 157                 digits--;
 158                 for (int i=0; i<9; i++) {
 159                         buffer[i] = buffer[i+1];
 160                 }
 161         }
 162
 163         /* zero out any leftovers */
 164         if (digits < 10) {
 165                 for (int i=digits; i<10; i++) {
 166                         buffer[i] = '\0';
 167                 }
 168         }
 169
 170         kprint(buffer, color);
 171         return digits;
 172 }