vgagraph.c

一个小型的操作系统,采用gcc进行开发,几千行的代码,方便初学者学习

/*
*  Snixos Project version 1.0, 2003.6
*  (C) Copyright 2003,2004,2005 Jockeyson,KeqiangGao <[e-mail]>
*  All Rights Reserved.
*  Distributed under the terms of the GNU General Public License.
*
*  This program is a free and open source software and you can redistribute 
*  it and/or modify it under the terms of the GNU General Public License as
*  published by the Free Software Foundation. As no any liability is assumed 
*  for any incidental or consequential damages in connection with the 
*  information or program fragments contained herein,so any exception arised
*  is at your own risk. It is ABSOLUTELY WITHOUT ANY WARRANTY.
*  Bug report please send to [e-mail] .
*/
/*
  vga.c   : VGA display management for 640*480 mono mode in SNIXOS project
  Author  : [e-mail]
  Time    : 2004.5

*/

#include "font_8x16.c"
#include "fatfs.h"
#include "stdio.h"

#define VGAMEM 0x0a0000
#define TEXTMALE 1
#define TEXTFEMALE 0
#define CHARHEIGHT (16+2)
#define ROWS 25
#define COLS 80
#define CURSOR_ICON 0XFF

unsigned char *vgamem;
int textCursorX, textCursorY;

void VGAScrInit(void);
void VGAPutChar_8x16(int x, int y, unsigned char ch, int mode);
void VGAPutCursor();
void VGAScrGotoxy(int x, int y);
void VGAscrollup(void);
void VGAWriteChar(char c);
void VGAHideCursor();

void VGAScrInit(void)
{
    int i, j;
    vgamem = (unsigned char *) VGAMEM;

    for (i = 0; i < 80; i++) {
	for (j = 0; j < 25; j++) {
	    VGAPutChar_8x16(j, i, ' ', TEXTMALE);
	}
    }
    VGAScrGotoxy(0, 0);
}

/* putchar for ascii 0~255 */
void VGAPutChar_8x16(int x, int y, unsigned char ch, int mode)
{
    int i;
    char *font;
    font = fontdata_8x16 + (ch % 256) * 16;
    /* x = x % 25; */
    y = y % 80;
    for (i = 0; i < 16; i++) {
	vgamem[(x * CHARHEIGHT) * 80 + 80 * i + y] =
	    (mode == TEXTMALE) ? font[i] : ~font[i];
    }
}

/* void VGAPutChinese_16X16(int x, int y, char *font) */
/* print 16x16 hz on x,y in 640*480 graph mode , monochrome */
/* x range:0~24,y range:0~39 */
void VGAPutChinese_16X16(int x, int y, char *ch, int mode)
{
    int i, j, col, seam;
    int qh, wh;
    unsigned char font[32];
    FILE *fp;
    int location;
    char *vgamem = (char *) VGAMEM;
    x = x % 25;
    y = y % 40;
    qh = (unsigned char) ch[0] - 0xa0;
    wh = (unsigned char) ch[1] - 0xa0;

    if ((fp = fopen("hzk16", "r")) == NULL) {
	printf("Can't open hzk16!\n");
	return;
    }
    /* seek font */
    location = (94 * (qh - 1) + (wh - 1)) * 32L;
    fseek(fp, location, 0);
    {
	int i = 0;
	unsigned char c;
	while (i < 32) {
	    font[i] = fgetc(fp);
	    i++;
	}
    }
    for (i = 0; i < 16; i++) {
	for (col = 0; col < 2; col++) {
	    /* 2 free lines for interval between rows */
	    vgamem[(x * CHARHEIGHT) * 80 + 80 * i + y * 2 + col] =
		(mode ==
		 TEXTMALE) ? font[i * 2 + col] : ~font[i * 2 + col];
	    /* font[i * 2 + col]; */
	}
    }
    fclose(fp);
}

/* print ascii(0~255) string at screen (x,y),where x=0~24, y=0~79, mode=0(textMale) 1=testFemale */
VGAPrintStr_8x16(int x, int y, char *str, int mode)
{
    int i = 0;
    while (str[i]) {
	VGAPutChar_8x16(x, y, str[i], mode);
	i++;
	y++;
    }
}

void VGAPutCursor()
{
    VGAPutChar_8x16(textCursorX, textCursorY, CURSOR_ICON, TEXTFEMALE);
}

void VGAScrGotoxy(int x, int y)
{
    textCursorX = x;
    textCursorY = y;
    VGAPutCursor();
}

void VGAscrollup(void)
{
    unsigned int org = VGAMEM + CHARHEIGHT * COLS;
    unsigned int dst = VGAMEM;
    unsigned int cnt = CHARHEIGHT * COLS * (ROWS - 1) / 2;
    unsigned int cnt2 = CHARHEIGHT * COLS / 2;
    unsigned int dst2 = VGAMEM + CHARHEIGHT * COLS * (ROWS - 1);

    asm("cld\n\t" "rep\n\t" "movsw\n\t"::"c"(cnt), "D"(dst), "S"(org));
    asm("cld\n\t" "rep\n\t" "stosw\n\t"::"a"(0x00), "c"(cnt2), "D"(dst2));
}

void VGAWriteChar(char c)
{
    if (c == '\n') {		/* CR LF */
	VGAPutChar_8x16(textCursorX, textCursorY, CURSOR_ICON, TEXTMALE);	/* hide cursor */
	VGAScrGotoxy(++textCursorX, 0);	/* VGAScrGotoxy(xcord,ycord) */
    } else if (c == '\t') {	/* horizontal Tab */
	VGAPutChar_8x16(textCursorX, textCursorY, CURSOR_ICON, TEXTMALE);	/* hide cursor */
	VGAScrGotoxy(textCursorX, textCursorY += 4);
    } else if (c == '\b') {	/* backspace */
	VGAPutChar_8x16(textCursorX, textCursorY, CURSOR_ICON, TEXTMALE);	/* hide cursor */
	VGAScrGotoxy(textCursorX, textCursorY -= 1);
	VGAWriteChar(' ');
	VGAPutChar_8x16(textCursorX, textCursorY, CURSOR_ICON, TEXTMALE);	/* hide cursor */
	VGAScrGotoxy(textCursorX, textCursorY -= 1);
	return;
    } else {
	VGAPutChar_8x16(textCursorX, textCursorY, (unsigned char) c,
			TEXTMALE);
	if (textCursorY == 79) {
	    VGAScrGotoxy(++textCursorX, 0);
	} else {
	    VGAScrGotoxy(textCursorX, ++textCursorY);
	}
    }

    /* off right edge */
    if (textCursorY > 79) {
	textCursorX++;
	VGAScrGotoxy(textCursorX, 0);
	/* VGAScrGotoxy( ++textCursorX,0); */
    }
    /* off bottom */
    if (textCursorX > 24) {
	VGAscrollup();
	VGAScrGotoxy(24, textCursorY);
    }
}

void VGAHideCursor()
{
    VGAPutChar_8x16(textCursorX, textCursorY, CURSOR_ICON, TEXTMALE);
}

/*
void VGADrawDot(int x,int y,int color)
args: x, y coordinate for the dot to be drawn, y: 0~639 x:0~479
      color: 0-black,1-white
*/
void VGADrawDot(int x, int y, int color)
{
    int VGAoffset, byteBits;
    char bitsMap[] = { 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80
    };
    x = x % 480;
    y = y % 640;
    VGAoffset = (x * 640 + y) / 8;
    byteBits = (x * 640 + y) % 8;
    *(vgamem + VGAoffset) =
	(color ==
	 1) ? vgamem[VGAoffset] | bitsMap[byteBits] : vgamem[VGAoffset] &
	(~bitsMap[byteBits]);
}