vga.c File Reference

#include "../lib/types.h"
#include "vga.h"
#include "kb.h"
#include "cm.h"
#include "../lib/err.h"
#include "../lib/utils.h"

Include dependency graph for vga.c:

Go to the source code of this file.

Functions
void	__scrl (void)
	scrl scrolls the vga text screen up by one row
void	__prt (int x, int y, const char *txt, uint8_t col)
	prt prints a string to the vga screen at a given position
void	__prtd (int x, int y, int num, uint8_t col)
	prtd prints a decimal integer to the vga screen
void	__prth (int x, int y, uint32_t hex, uint8_t col)
	prth prints a 32 bit hex value to the vga screen
void	__clscr (void)
	clscr clears the entire vga text screen
void	__rdln (char *buffer, int maxlen)
	rdln reads a line of text input from the keyboard
void	__drw (int x1, int y1, int x2, int y2, uint8_t col)
	drw draws a line on the vga screen using '#' characters
void	__pchr (int x, int y, char chr, uint8_t col)
	pchr prints a single raw character to the vga screen

Variables
uint16_t *	vga = (uint16_t*)0xB8000
	the vga framebuffer pointer

Function Documentation

__clscr()

void __clscr

(

void

)

clscr clears the entire vga text screen

clscr is a function that fills all 2000 vga cells with spaces using the default white-on-black color attribute

using clscr is done with

#include "../io/vga.h" //or just vga.h
clscr();

See also

scrl(), prt()

Definition at line 193 of file vga.c.

References vga.

__drw()

void __drw	(	int	x1,
		int	y1,
		int	x2,
		int	y2,
		uint8_t	col )

drw draws a line on the vga screen using '#' characters

drw is a function that draws horizontal, vertical, or diagonal lines on the vga screen using bresenhams line algorithm for the diagonal case

Parameters

x1,the	starting column (0-79)
y1,the	starting row (0-24)
x2,the	ending column (0-79)
y2,the	ending row (0-24)
col,the	vga color attribute byte

using drw is done with

#include "../io/vga.h" //or just vga.h
drw(10, 5, 50, 5, 0x0A); //horizontal green line

See also

prt(), pchr()

Definition at line 280 of file vga.c.

References abs(), assert, and prt.

__pchr()

void __pchr	(	int	x,
		int	y,
		char	chr,
		uint8_t	col )

pchr prints a single raw character to the vga screen

pchr is a function that prints a single character at a given screen position, useful for printing extended ascii characters

Parameters

x,the	column to print at
y,the	row to print at
chr,the	raw character to print (e.g. a char literal)
col,the	vga color attribute byte

using pchr is done with

#include "../io/vga.h" //or just vga.h
pchr(40, 12, 0xDB, 0x0F); //solid block char

See also

prt(), drw()

Definition at line 352 of file vga.c.

References prt.

__prt()

void __prt	(	int	x,
		int	y,
		const char *	txt,
		uint8_t	col )

prt prints a string to the vga screen at a given position

prt is a function that writes a null-terminated string to the vga text framebuffer handling newlines, line wrapping, and scrolling

Parameters

x,the	column to start printing at (0-79)
y,the	row to start printing at (0-24)
txt,the	null-terminated string to print
col,the	vga color attribute byte (0x00-0xFF)

using prt is done with

#include "../io/vga.h" //or just vga.h
prt(0, 0, "hello, kernel!", 0x0F); //white text on black bg

See also

scrl(), pchr(), prtd(), prth()

Definition at line 62 of file vga.c.

References assert, NULL, scrl, and vga.

__prtd()

void __prtd	(	int	x,
		int	y,
		int	num,
		uint8_t	col )

prtd prints a decimal integer to the vga screen

prtd is a function that converts an integer to a decimal string using itoa and prints it at the given position

Parameters

x,the	column to start printing at
y,the	row to start printing at
num,the	signed integer to print
col,the	vga color attribute byte

using prtd is done with

#include "../io/vga.h" //or just vga.h
prtd(0, 5, 42, 0x0F);

See also

prt(), prth(), itoa()

Definition at line 138 of file vga.c.

References itoa(), and prt.

__prth()

void __prth	(	int	x,
		int	y,
		uint32_t	hex,
		uint8_t	col )

prth prints a 32 bit hex value to the vga screen

prth is a function that converts a uint32_t to an 8 character hexadecimal string and prints it at the given position

Parameters

x,the	column to start printing at
y,the	row to start printing at
hex,the	32 bit unsigned integer to print in hex
col,the	vga color attribute byte

using prth is done with

#include "../io/vga.h" //or just vga.h
prth(0, 0, 0x00007C00, 0x0F);

See also

prt(), prtd()

Definition at line 162 of file vga.c.

References prt.

__rdln()

void __rdln	(	char *	buffer,
		int	maxlen )

rdln reads a line of text input from the keyboard

rdln is a function that reads keyboard input into a buffer, handling backspace, echoing characters, and returning on enter

Parameters

buffer,the	buffer to store the input string in
maxlen,the	maximum length of the input including null

using rdln is done with

#include "../io/vga.h" //or just vga.h
char input[100];
rdln(input, 100);

See also

gtchr(), prt(), cob()

Definition at line 216 of file vga.c.

References assert, cnb, cob, gtchr, NULL, prt, and scrl.

__scrl()

void __scrl

(

void

)

scrl scrolls the vga text screen up by one row

scrl is a function that shifts all rows up by one and clears the bottom row, used for when text output fills the screen

scrl is called automatically by prt when y goes past 24

See also

prt(), clscr()

Definition at line 30 of file vga.c.

References vga.

Variable Documentation

vga

uint16_t* vga = (uint16_t*)0xB8000

the vga framebuffer pointer

vga points to the vga text-mode framebuffer at physical address 0xB8000, each cell is a uint16_t with the lower byte as the character and the upper byte as the color attribute

See also

prt(), clscr(), scrl()

Definition at line 18 of file vga.c.

Referenced by __clscr(), __panic(), __prt(), and __scrl().