forked from BSB-WS23/mpstubs
120 lines
4.6 KiB
C++
120 lines
4.6 KiB
C++
/*! \file
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* \brief \ref TextMode provides a basic interface to display a character in VGA-compatible text mode
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*/
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#pragma once
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#include "types.h"
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/*! \brief Basic operations in the VGA-compatible text mode
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* \ingroup io
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*
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* This class provides an interface to access the screen in text mode, with
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* access directly on the hardware level, i.e. the video memory and the
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* I/O ports of the graphics card.
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*/
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class TextMode {
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public:
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static const unsigned ROWS = 25; ///< Visible rows in text mode
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static const unsigned COLUMNS = 80; ///< Visible columns in text mode
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/*! \brief CGA color palette
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*
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* Colors for the attribute byte.
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* All 16 colors can be used for the foreground while the background colors
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* are limited to the first eight (from`BLACK` to `LIGHT_GREY`)
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*/
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enum Color {
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BLACK, ///< Black (fore- and background)
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BLUE, ///< Blue (fore- and background)
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GREEN, ///< Green (fore- and background)
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CYAN, ///< Cyan (fore- and background)
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RED, ///< Red (fore- and background)
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MAGENTA, ///< Magenta (fore- and background)
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BROWN, ///< Brown (fore- and background)
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LIGHT_GREY, ///< Light grey (fore- and background)
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DARK_GREY, ///< Dark grey (foreground only)
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LIGHT_BLUE, ///< Light blue (foreground only)
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LIGHT_GREEN, ///< Light green (foreground only)
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LIGHT_CYAN, ///< Light cyan (foreground only)
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LIGHT_RED, ///< Light red (foreground only)
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LIGHT_MAGENTA, ///< Light magenta (foreground only)
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YELLOW, ///< Yellow (foreground only)
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WHITE ///< White (foreground only)
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};
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/*! \brief Structure of a character attribute
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* consists of 4 bit fore- and 3 bit background color, and a single blink bit.
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*
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* [Bit fields](https://en.cppreference.com/w/cpp/language/bit_field) can
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* notably simplify the access and code readability.
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*
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* \note [Type punning](https://en.wikipedia.org/wiki/Type_punning#Use_of_union)
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* is indeed undefined behavior in C++. However, *gcc* explicitly allows this construct as a
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* [language extension](https://gcc.gnu.org/bugs/#nonbugs).
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* Some compilers ([other than gcc](https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#Type%2Dpunning)
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* might allow this feature only by disabling strict aliasing (`-fno-strict-aliasing`).
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* In \StuBS we use this feature extensively due to the improved code readability.
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*/
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union Attribute {
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struct {
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uint8_t foreground : 4; ///< `.... XXXX` Foreground color
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uint8_t background : 3; ///< `.XXX ....` Background color
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uint8_t blink : 1; ///< `X... ....` Blink
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} __attribute__((packed));
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uint8_t value; ///< combined value
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/*! \brief Attribute constructor (with default values)
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*
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* \todo Complete constructor
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*
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* \param foreground Foreground color (Default: \ref LIGHT_GREY)
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* \param background Background color (Default: \ref BLACK)
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* \param blink Blink if `true` (default: no blinking)
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*/
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explicit Attribute(Color foreground = LIGHT_GREY, Color background = BLACK, bool blink = false)
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{ //NOLINT
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(void) foreground;
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(void) background;
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(void) blink;
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}
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} __attribute__((packed)); // prevent padding by the compiler
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/*! \brief Set the keyboard hardware cursor to absolute screen position
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*
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* \todo Implement the method using \ref IOPort
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*
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* \param abs_x absolute column of the keyboard hardware cursor
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* \param abs_y absolute row of the keyboard hardware cursor
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*/
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static void setCursor(unsigned abs_x, unsigned abs_y);
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/*! \brief Retrieve the keyboard hardware cursor position on screen
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*
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* \todo Implement the method using the \ref IOPort
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*
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* \param abs_x absolute column of the keyboard hardware cursor
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* \param abs_y absolute row of the keyboard hardware cursor
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*/
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static void getCursor(unsigned& abs_x, unsigned& abs_y);
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/*! \brief Basic output of a character at a specific position on the screen.
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*
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* This method outputs the given character at the absolute screen position
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* (`x`, `y`) with the specified color attribute.
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*
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* The position (`0`,`0`) indicates the upper left corner of the screen.
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* The attribute defines characteristics such as background color,
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* foreground color and blinking.
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*
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* \param abs_x Column (`abs_x` < \ref COLUMNS) in which the character should be displayed
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* \param abs_y Row (`abs_y` < \ref ROWS) in which the character should be displayed
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* \param character Character to be displayed
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* \param attrib Attribute with color settings
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* \todo Implement the method
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*/
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static void show(unsigned abs_x, unsigned abs_y, char character, Attribute attrib = Attribute());
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};
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