98 lines
2.3 KiB
C
98 lines
2.3 KiB
C
#include "vga.h"
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#define VGA_WIDTH 80
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#define VGA_HEIGHT 25
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#define VGA_MEM_ADDR 0xb8000
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#define CURSOR_HOME (VGA_HEIGHT-1)*VGA_WIDTH
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#define CURSOR_CHR 177;
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unsigned int cursor_loc = CURSOR_HOME;
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unsigned char fgcolor;
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unsigned char bgcolor;
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unsigned short blank;
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static unsigned char vga_entry_color(enum vga_color fg, enum vga_color bg) {
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return fg | bg << 4;
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}
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unsigned short vga_blank_entry() {
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return vga_entry_color(fgcolor, bgcolor) << 8;
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}
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void draw_cursor(void) {
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*((unsigned char *)VGA_MEM_ADDR + cursor_loc * 2) = CURSOR_CHR;
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*((unsigned char *)VGA_MEM_ADDR+1 + cursor_loc * 2) = vga_entry_color(fgcolor, bgcolor);
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}
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void vga_set_color(enum vga_color fg, enum vga_color bg) {
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fgcolor = fg;
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bgcolor = bg;
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}
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void vga_init(enum vga_color fg, enum vga_color bg) {
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vga_set_color(fg, bg);
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blank = vga_blank_entry();
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cls();
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}
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void cls(void) {
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int i;
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for (i=0; i<VGA_HEIGHT*VGA_WIDTH;i++) {
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*((unsigned short *) VGA_MEM_ADDR+i) = blank;
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}
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}
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void scroll(void) {
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int y;
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int x;
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*((unsigned short *) VGA_MEM_ADDR+cursor_loc) = blank;
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for (y=0;y<VGA_HEIGHT;y++) {
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for (x = 0;x<VGA_WIDTH;x++) {
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*((unsigned short *) VGA_MEM_ADDR+y*VGA_WIDTH+x) = *((unsigned short *) VGA_MEM_ADDR+(y+1)*VGA_WIDTH+x);
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}
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}
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for (x=0;x<VGA_WIDTH;x++) {
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*((unsigned short *) VGA_MEM_ADDR+CURSOR_HOME+x) = blank;
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}
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cursor_loc = CURSOR_HOME;
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draw_cursor();
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}
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void putchar(unsigned char chr) {
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if (chr == '\n') {
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scroll();
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return;
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}
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*((unsigned char *) VGA_MEM_ADDR+cursor_loc * 2) = chr;
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*((unsigned char *) VGA_MEM_ADDR+1+cursor_loc * 2) = vga_entry_color(fgcolor, bgcolor);
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cursor_loc++;
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if (cursor_loc >= VGA_HEIGHT*VGA_WIDTH) {
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scroll();
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}
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draw_cursor();
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}
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void vga_write(const char* text) {
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int i = 0;
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while(text[i]) {
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putchar(text[i]);
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i++;
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}
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}
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void vga_write_color( const char* text, enum vga_color fg, enum vga_color bg) {
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unsigned char prevfg = fgcolor;
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unsigned char prevbg = bgcolor;
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vga_set_color(fg, bg);
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vga_write(text);
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fgcolor = prevfg;
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bgcolor = prevbg;
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}
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void vga_write_line(const char* text) {
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if (cursor_loc != CURSOR_HOME) {
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scroll();
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}
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vga_write(text);
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scroll();
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}
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void vga_write_line_color(const char* text, enum vga_color fg, enum vga_color bg) {
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unsigned char prevfg = fgcolor;
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unsigned char prevbg = bgcolor;
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vga_set_color(fg, bg);
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vga_write_line(text);
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fgcolor = prevfg;
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bgcolor = prevbg;
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}
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