vga.c File Reference

Implementation of Video Graphics Array (VGA) drivers. More...

Classes
struct	vga_ops_t
	VGA pointers for drawing operations. More...
struct	vga_font_t
	VGA font details. More...
struct	vga_driver_t
	VGA driver details. More...

Macros
#define	__DEBUG_HEADER__   "[VGA ]"
	Change header.
#define	__DEBUG_LEVEL__   LOGLEVEL_NOTICE
	Set log level.
#define	AC_INDEX   0x03C0
	Attribute Controller index port.
#define	AC_WRITE   0x03C0
	Attribute Controller write port.
#define	AC_READ   0x03C1
	Attribute Controller data port.
#define	MISC_WRITE   0x03C2
	Miscellaneous output register.
#define	MISC_READ   0x03CC
	Miscellaneous input register.
#define	SC_INDEX   0x03C4
	Sequence controller index.
#define	SC_DATA   0x03C5
	Sequence controller data.
#define	PALETTE_MASK   0x03C6
	DAC Mask Register.
#define	PALETTE_READ   0x03C7
	Controls the DAC.
#define	PALETTE_INDEX   0x03C8
	Controls the DAC index.
#define	PALETTE_DATA   0x03C9
	Controls the DAC data.
#define	GC_INDEX   0x03CE
	Graphics controller index.
#define	GC_DATA   0x03CF
	Graphics controller data.
#define	CRTC_INDEX   0x03D4
	CRT controller index.
#define	CRTC_DATA   0x03D5
	CRT controller data.
#define	INPUT_STATUS_READ   0x03DA
	By reading this port it'll go to the index state.
#define	MODE_NUM_SEQ_REGS   5
	Number of sequencer registers.
#define	MODE_NUM_CRTC_REGS   25
	Number of CRTC registers.
#define	MODE_NUM_GC_REGS   9
	Number of Graphics Controller (GC) registers.
#define	MODE_NUM_AC_REGS   (16 + 5)
	Number of Attribute Controller (AC) registers.
#define	MODE_NUM_REGS   (1 + MODE_NUM_SEQ_REGS + MODE_NUM_CRTC_REGS + MODE_NUM_GC_REGS + MODE_NUM_AC_REGS)
	Total number of registers.

Functions
static char *	__get_seg (void)
	Returns the video address. More...
void	__vga_set_color_map (unsigned int index, unsigned char r, unsigned char g, unsigned char b)
	Sets the color at the given index. More...
void	__vga_get_color_map (unsigned int index, unsigned char *r, unsigned char *g, unsigned char *b)
	Gets the color at the given index. More...
static void	__save_palette (palette_entry_t *p, size_t size)
	Saves the current palette in p. More...
static void	__load_palette (palette_entry_t *p, size_t size)
	Loads the palette p. More...
static void	__set_plane (unsigned int plane)
	Sets the current plane. More...
static unsigned	__get_plane (void)
	Returns the current plane. More...
static unsigned char	__read_byte (unsigned int offset)
	Reads from the video memory. More...
static void	__write_byte (unsigned int offset, unsigned char value)
	Writes onto the video memory. More...
static void	__set_mode (vga_mode_t *vga_mode)
	Sets the given mode. More...
static void	__read_registers (vga_mode_t *vga_mode)
	Reads the VGA registers. More...
static void	__write_font (unsigned char *buf, unsigned font_height)
	Writes the font. More...
static unsigned int	__reverse_bits (char num)
	Reverses the bits of the given number. More...
static void	__write_pixel_1 (int x, int y, unsigned char c)
	Writes a pixel. More...
static unsigned	__read_pixel_1 (unsigned x, unsigned y)
	Reads a pixel. More...
static void	__write_pixel_2 (int x, int y, unsigned char c)
	Writes a pixel. More...
static unsigned	__read_pixel_2 (unsigned x, unsigned y)
	Reads a pixel. More...
static void	__write_pixel_4 (int x, int y, unsigned char color)
	Writes a pixel. More...
static unsigned	__read_pixel_4 (int x, int y)
	Reads a pixel. More...
static void	__write_pixel_8 (int x, int y, unsigned char color)
	Writes a pixel. More...
static unsigned	__read_pixel_8 (int x, int y)
	Reads a pixel. More...
int	vga_is_enabled (void)
	Checks if the VGA is enabled. More...
int	vga_width (void)
	Returns the width of the screen. More...
int	vga_height (void)
	Returns the height of the screen. More...
void	vga_draw_pixel (int x, int y, unsigned char color)
	Draws a pixel at the given position. More...
unsigned int	vga_read_pixel (int x, int y)
	Reads a pixel at the given position. More...
void	vga_draw_char (int x, int y, unsigned char c, unsigned char color)
	Draws a character at the given position. More...
void	vga_draw_string (int x, int y, const char *str, unsigned char color)
	Draws a string at the given position. More...
void	vga_draw_line (int x0, int y0, int x1, int y1, unsigned char color)
	Draws a line from point 1 to point 2. More...
void	vga_draw_rectangle (int sx, int sy, int w, int h, unsigned char color)
	Draws a rectangle provided the position of the starting corner and the ending corner. More...
void	vga_draw_circle (int xc, int yc, int r, unsigned char color)
	Draws a circle provided the position of the center and the radius. More...
void	vga_draw_triangle (int x1, int y1, int x2, int y2, int x3, int y3, unsigned char color)
	Draws a triangle. More...
void	vga_run_test (void)
	Run some VGA tests.
void	vga_initialize (void)
	Initializes the VGA.
void	vga_finalize (void)
	Finalizes the VGA.
static void	__vga_clear_cursor (void)
	Clears the character at the cursor.
static void	__vga_draw_cursor (void)
	Draws the cursor.
void	vga_putc (int c)
	Print the given character on the screen. More...
void	vga_puts (const char *str)
	Prints the given string on the screen. More...
void	vga_move_cursor (unsigned int x, unsigned int y)
	Move the cursor at the position x, y on the screen. More...
void	vga_get_cursor_position (unsigned int *x, unsigned int *y)
	Returns cursor's position on the screen. More...
void	vga_get_screen_size (unsigned int *width, unsigned int *height)
	Returns screen size. More...
void	vga_clear_screen (void)
	Clears the screen.
void	vga_new_line (void)
	Move to the following line (the effect of character).
void	vga_update (void)
	Updates the graphic elements.
void	vga_set_color (unsigned int color)
	Change the color. More...

Variables
static bool_t	vga_enable = false
	Is VGA enabled.
palette_entry_t	stored_palette [256]
	The stored palette.
char	vidmem [262144]
	A buffer for storing a copy of the video memory.
static vga_driver_t *	driver = NULL
	Current driver.
static vga_ops_t	ops_720_480_16
	Operations for 720*480, and 16-bit color video. More...
static vga_ops_t	ops_640_480_16
	Operations for 640*480, and 16-bit color video. More...
static vga_ops_t	ops_320_200_256
	Operations for 320*200, and 256-bit color video. More...
static vga_font_t	font_4x6
	4x6 font. More...
static vga_font_t	font_5x6
	5x6 font. More...
static vga_font_t	font_8x8
	8x8 font. More...
static vga_font_t	font_8x14
	8x14 font. More...
static vga_font_t	font_8x16
	8x16 font. More...
static vga_driver_t	driver_720_480_16
	Drivers for 720*480, and 16-bit color video. More...
static vga_driver_t	driver_640_480_16
	Drivers for 640*480, and 16-bit color video. More...
static vga_driver_t	driver_320_200_256
	Drivers for 320*200, and 16-bit color video. More...
static int	_x = 0
	Current x coordinate of the cursor.
static int	_y = 0
	Current y coordinate of the cursor.
static unsigned char	_color = 7
	Current color.
static int	_cursor_state = 0
	Current state of the cursor.

Detailed Description

Implementation of Video Graphics Array (VGA) drivers.

Copyright

(c) 2014-2024 This file is distributed under the MIT License. See LICENSE.md for details.

Function Documentation

__get_plane()

static unsigned __get_plane ( void  )

inlinestatic

Returns the current plane.

Returns

the current plane.

__get_seg()

static char* __get_seg ( void  )

inlinestatic

Returns the video address.

Returns

pointer to the video.

__load_palette()

static void __load_palette ( palette_entry_t *  p, size_t  size  )

static

Loads the palette p.

Parameters

p	palette we are going to load.
size	the size of the palette.

__read_byte()

static unsigned char __read_byte ( unsigned int  offset )

static

Reads from the video memory.

Parameters

offset

where we are going to read.

Returns

the value we read.

__read_pixel_1()

static unsigned __read_pixel_1 ( unsigned  x, unsigned  y  )

inlinestatic

Reads a pixel.

Parameters

x	x coordinates.
y	y coordinates.

Returns

the pixel value.

__read_pixel_2()

static unsigned __read_pixel_2 ( unsigned  x, unsigned  y  )

inlinestatic

Reads a pixel.

Parameters

x	x coordinates.
y	y coordinates.

Returns

the pixel value.

__read_pixel_4()

static unsigned __read_pixel_4 ( int  x, int  y  )

inlinestatic

Reads a pixel.

Parameters

x	x coordinates.
y	y coordinates.

Returns

the pixel value.

__read_pixel_8()

static unsigned __read_pixel_8 ( int  x, int  y  )

inlinestatic

Reads a pixel.

Parameters

x	x coordinates.
y	y coordinates.

Returns

the pixel value.

__read_registers()

static void __read_registers ( vga_mode_t *  vga_mode )

static

Reads the VGA registers.

Parameters

vga_mode

the current VGA mode.

__reverse_bits()

static unsigned int __reverse_bits ( char  num )

inlinestatic

Reverses the bits of the given number.

Parameters

num	the number of which we want to reverse the bits.

Returns

reversed bits.

__save_palette()

static void __save_palette ( palette_entry_t *  p, size_t  size  )

static

Saves the current palette in p.

Parameters

p	output variable where we save the palette.
size	the size of the palette.

__set_mode()

static void __set_mode ( vga_mode_t *  vga_mode )

static

Sets the given mode.

Parameters

vga_mode

the new mode we set.

__set_plane()

static void __set_plane ( unsigned int  plane )

inlinestatic

Sets the current plane.

Parameters

plane

the plane to set.

__vga_get_color_map()

void __vga_get_color_map	(	unsigned int	index,
		unsigned char *	r,
		unsigned char *	g,
		unsigned char *	b
	)

Gets the color at the given index.

Parameters

index	index of the palette we want to read.
r	output value for red.
g	output value for green.
b	output value for blue.

__vga_set_color_map()

void __vga_set_color_map	(	unsigned int	index,
		unsigned char	r,
		unsigned char	g,
		unsigned char	b
	)

Sets the color at the given index.

Parameters

index	index of the palette we want to change.
r	red.
g	green.
b	blue.

__write_byte()

static void __write_byte ( unsigned int  offset, unsigned char  value  )

static

Writes onto the video memory.

Parameters

offset	where we are going to write.
value	the value to write.

__write_font()

static void __write_font ( unsigned char *  buf, unsigned  font_height  )

static

Writes the font.

Parameters

buf	buffer where the font resides.
font_height	the height of the font.

__write_pixel_1()

static void __write_pixel_1 ( int  x, int  y, unsigned char  c  )

inlinestatic

Writes a pixel.

Parameters

x	x coordinates.
y	y coordinates.
c	color.

__write_pixel_2()

static void __write_pixel_2 ( int  x, int  y, unsigned char  c  )

inlinestatic

Writes a pixel.

Parameters

x	x coordinates.
y	y coordinates.
c	color.

__write_pixel_4()

static void __write_pixel_4 ( int  x, int  y, unsigned char  color  )

inlinestatic

Writes a pixel.

Parameters

x	x coordinates.
y	y coordinates.
color	the color.

__write_pixel_8()

static void __write_pixel_8 ( int  x, int  y, unsigned char  color  )

inlinestatic

Writes a pixel.

Parameters

x	x coordinates.
y	y coordinates.
color	the color.

vga_draw_char()

void vga_draw_char	(	int	x,
		int	y,
		unsigned char	c,
		unsigned char	color
	)

Draws a character at the given position.

Parameters

x	x-axis position.
y	y-axis position.
c	character to draw.
color	color of the character.

vga_draw_circle()

void vga_draw_circle	(	int	xc,
		int	yc,
		int	r,
		unsigned char	color
	)

Draws a circle provided the position of the center and the radius.

Parameters

xc	x-axis position.
yc	y-axis position.
r	radius.
color	used to draw the circle.

vga_draw_line()

void vga_draw_line	(	int	x0,
		int	y0,
		int	x1,
		int	y1,
		unsigned char	color
	)

Draws a line from point 1 to point 2.

Parameters

x0	point 1 x-axis position.
y0	point 1 y-axis position.
x1	point 2 x-axis position.
y1	point 2 y-axis position.
color	color of the line.

vga_draw_pixel()

void vga_draw_pixel	(	int	x,
		int	y,
		unsigned char	color
	)

Draws a pixel at the given position.

Parameters

x	x-axis position.
y	y-axis position.
color	color of the character.

vga_draw_rectangle()

void vga_draw_rectangle	(	int	sx,
		int	sy,
		int	w,
		int	h,
		unsigned char	color
	)

Draws a rectangle provided the position of the starting corner and the ending corner.

Parameters

sx	top-left corner x-axis position.
sy	top-left corner y-axis position.
w	width.
h	height.
color	color of the rectangle.

vga_draw_string()

void vga_draw_string	(	int	x,
		int	y,
		const char *	str,
		unsigned char	color
	)

Draws a string at the given position.

Parameters

x	x-axis position.
y	y-axis position.
str	string to draw.
color	color of the character.

vga_draw_triangle()

void vga_draw_triangle	(	int	x1,
		int	y1,
		int	x2,
		int	y2,
		int	x3,
		int	y3,
		unsigned char	color
	)

Draws a triangle.

Parameters

x1	1st point x-axis position.
y1	1st point y-axis position.
x2	2nd point x-axis position.
y2	2nd point y-axis position.
x3	3rd point x-axis position.
y3	3rd point y-axis position.
color	used to draw the triangle.

vga_get_cursor_position()

void vga_get_cursor_position	(	unsigned int *	x,
		unsigned int *	y
	)

Returns cursor's position on the screen.

Parameters

x	The output x coordinate.
y	The output y coordinate.

vga_get_screen_size()

void vga_get_screen_size	(	unsigned int *	width,
		unsigned int *	height
	)

Returns screen size.

Parameters

width	The screen width.
height	The screen height.

vga_height()

int vga_height

(

void

)

Returns the height of the screen.

Returns

the height of the screen.

vga_is_enabled()

int vga_is_enabled

(

void

)

Checks if the VGA is enabled.

Returns

1 if enabled, 0 otherwise.

vga_move_cursor()

void vga_move_cursor	(	unsigned int	x,
		unsigned int	y
	)

Move the cursor at the position x, y on the screen.

Parameters

x	The x coordinate.
y	The y coordinate.

vga_putc()

void vga_putc

(

int

c

)

Print the given character on the screen.

Parameters

c	The character to print.

vga_puts()

void vga_puts

(

const char *

str

)

Prints the given string on the screen.

Parameters

str	The string to print.

vga_read_pixel()

unsigned int vga_read_pixel	(	int	x,
		int	y
	)

Reads a pixel at the given position.

Parameters

x	x-axis position.
y	y-axis position.

Returns

the pixel we read.

vga_set_color()

void vga_set_color

(

unsigned int

color

)

Change the color.

Parameters

color

the color to set.

vga_width()

int vga_width

(

void

)

Returns the width of the screen.

Returns

the width of the screen.

Variable Documentation

driver_320_200_256

vga_driver_t driver_320_200_256

static

Initial value:

= {
    .width   = 320,
    .height  = 200,
    .bpp     = 256,
    .address = (char *)NULL,
    .ops     = &ops_320_200_256,
}

Drivers for 320*200, and 16-bit color video.

driver_640_480_16

vga_driver_t driver_640_480_16

static

Initial value:

= {
    .width   = 640,
    .height  = 480,
    .bpp     = 16,
    .address = (char *)NULL,
    .ops     = &ops_640_480_16,
}

Drivers for 640*480, and 16-bit color video.

driver_720_480_16

vga_driver_t driver_720_480_16

static

Initial value:

= {
    .width   = 720,
    .height  = 480,
    .bpp     = 16,
    .address = (char *)NULL,
    .ops     = &ops_720_480_16,
}

Drivers for 720*480, and 16-bit color video.

font_4x6

vga_font_t font_4x6

static

Initial value:

= {
    .font   = arr_4x6_font,
    .width  = 4,
    .height = 6,
}

4x6 font.

font_5x6

vga_font_t font_5x6

static

Initial value:

= {
    .font   = arr_5x6_font,
    .width  = 5,
    .height = 6,
}

5x6 font.

font_8x14

vga_font_t font_8x14

static

Initial value:

= {
    .font   = arr_8x14_font,
    .width  = 8,
    .height = 14,
}

8x14 font.

font_8x16

vga_font_t font_8x16

static

Initial value:

= {
    .font   = arr_8x16_font,
    .width  = 8,
    .height = 16,
}

8x16 font.

font_8x8

vga_font_t font_8x8

static

Initial value:

= {
    .font   = arr_8x8_font,
    .width  = 8,
    .height = 8,
}

8x8 font.

ops_320_200_256

vga_ops_t ops_320_200_256

static

Initial value:

= {
    .write_pixel = __write_pixel_8,
    .read_pixel  = __read_pixel_8,
    .draw_rect   = NULL,
    .fill_rect   = NULL,
}

Operations for 320*200, and 256-bit color video.

ops_640_480_16

vga_ops_t ops_640_480_16

static

Initial value:

= {
    .write_pixel = __write_pixel_4,
    .read_pixel  = __read_pixel_4,
    .draw_rect   = NULL,
    .fill_rect   = NULL,
}

Operations for 640*480, and 16-bit color video.

ops_720_480_16

vga_ops_t ops_720_480_16

static

Initial value:

= {
    .write_pixel = __write_pixel_4,
    .read_pixel  = __read_pixel_4,
    .draw_rect   = NULL,
    .fill_rect   = NULL,
}

Operations for 720*480, and 16-bit color video.