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TextMode Class Reference

Basic operations in the VGA-compatible text mode. More...

#include <machine/textmode.h>

+ Inheritance diagram for TextMode:
+ Collaboration diagram for TextMode:

Classes

union  Attribute
 Structure of a character attribute consists of 4 bit fore- and 3 bit background color, and a single blink bit. More...
 
struct  Attribute.__unnamed53__
 
struct  Cell
 Structure for a cell in text mode. More...
 

Public Types

enum  Color {
  BLACK ,
  BLUE ,
  GREEN ,
  CYAN ,
  RED ,
  MAGENTA ,
  BROWN ,
  LIGHT_GREY ,
  DARK_GREY ,
  LIGHT_BLUE ,
  LIGHT_GREEN ,
  LIGHT_CYAN ,
  LIGHT_RED ,
  LIGHT_MAGENTA ,
  YELLOW ,
  WHITE
}
 CGA color palette. More...
 

Static Public Member Functions

static void setCursor (unsigned abs_x, unsigned abs_y)
 Set the keyboard hardware cursor to absolute screen position. More...
 
static void getCursor (unsigned &abs_x, unsigned &abs_y)
 Retrieve the keyboard hardware cursor position on screen. More...
 
static void show (unsigned abs_x, unsigned abs_y, char character, Attribute attrib=Attribute())
 Basic output of a character at a specific position on the screen. More...
 
static void show (int abs_x, int abs_y, char character, Attribute attrib=Attribute())
 Basic output of a character at a specific position on the screen. More...
 

Static Public Attributes

static const unsigned ROWS = 25
 Visible rows in text mode.
 
static const unsigned COLUMNS = 80
 Visible columns in text mode.
 

Protected Member Functions

 TextMode ()
 Default constructor.
 

Static Protected Attributes

static Cell *const TEXT_BUFFER_BASE = reinterpret_cast<TextMode::Cell *>(0xb8000)
 Base address for linear text buffer in video memory.
 

Detailed Description

Basic operations in the VGA-compatible text mode.

This class provides an interface to access the screen in text mode, with access directly on the hardware level, i.e. the video memory and the I/O ports of the graphics card.

Class Documentation

struct TextMode::Attribute.__unnamed53__
Class Members
uint8_t foreground: 4 .... XXXX Foreground color
uint8_t background: 3 .XXX .... Background color
uint8_t blink: 1 X... .... Blink

Member Enumeration Documentation

enum TextMode::Color

CGA color palette.

Colors for the attribute byte. All 16 colors can be used for the foreground while the background colors are limited to the first eight (fromBLACK to LIGHT_GREY)

Enumerator
BLACK 

Black (fore- and background)

BLUE 

Blue (fore- and background)

GREEN 

Green (fore- and background)

CYAN 

Cyan (fore- and background)

RED 

Red (fore- and background)

MAGENTA 

Magenta (fore- and background)

BROWN 

Brown (fore- and background)

LIGHT_GREY 

Light grey (fore- and background)

DARK_GREY 

Dark grey (foreground only)

LIGHT_BLUE 

Light blue (foreground only)

LIGHT_GREEN 

Light green (foreground only)

LIGHT_CYAN 

Light cyan (foreground only)

LIGHT_RED 

Light red (foreground only)

LIGHT_MAGENTA 

Light magenta (foreground only)

YELLOW 

Yellow (foreground only)

WHITE 

White (foreground only)

Member Function Documentation

void TextMode::setCursor ( unsigned  abs_x,
unsigned  abs_y 
)
static

Set the keyboard hardware cursor to absolute screen position.

Todo:
Implement the method using IOPort
Parameters
abs_xabsolute column of the keyboard hardware cursor
abs_yabsolute row of the keyboard hardware cursor
void TextMode::getCursor ( unsigned &  abs_x,
unsigned &  abs_y 
)
static

Retrieve the keyboard hardware cursor position on screen.

Todo:
Implement the method using the IOPort
Parameters
abs_xabsolute column of the keyboard hardware cursor
abs_yabsolute row of the keyboard hardware cursor
void TextMode::show ( unsigned  abs_x,
unsigned  abs_y,
char  character,
Attribute  attrib = Attribute() 
)
static

Basic output of a character at a specific position on the screen.

This method outputs the given character at the absolute screen position (x, y) with the specified color attribute.

The position (0,0) indicates the upper left corner of the screen. The attribute defines characteristics such as background color, foreground color and blinking.

Parameters
abs_xColumn (abs_x < COLUMNS) in which the character should be displayed
abs_yRow (abs_y < ROWS) in which the character should be displayed
characterCharacter to be displayed
attribAttribute with color settings
Todo:
Implement the method
void TextMode::show ( int  abs_x,
int  abs_y,
char  character,
Attribute  attrib = Attribute() 
)
static

Basic output of a character at a specific position on the screen.

This method outputs the given character at the absolute screen position (x, y) with the specified color attribute. Negative coordinates are interpreted relative to the right (x) and bottom (y) border.

Parameters
abs_xColumn (-COLUMNS ≤ abs_x < COLUMNS) in which the character should be displayed – using the right border (COLUMNS) as reference for negative values.
abs_yRow (-ROWS ≤ abs_y < ROWS) in which the character should be displayed – using the bottom border (ROWS) as reference for negative values.
characterCharacter to be displayed
attribAttribute with color settings
Optional:
Implement this method (it can either use or replace show(unsigned, unsigned, char, Attribute))
The documentation for this class was generated from the following files: