www.pudn.com > MessageQueue.zip > TextOut.c

/* 
Copyright (C) 2004  Liu Ge 
 
This program is free software; you can redistribute it and/or 
modify it under the terms of the GNU General Public License 
as published by the Free Software Foundation; either version 2 
of the License, or (at your option) any later version. 
 
This program is distributed in the hope that it will be useful, 
but WITHOUT ANY WARRANTY; without even the implied warranty of 
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
GNU General Public License for more details. 
 
You should have received a copy of the GNU General Public License 
along with this program; if not, write to the Free Software 
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA. 
 
*/ 
#include "TextOut.h" 
 
typedef	struct 
{ 
	unsigned char bChar; 
	unsigned char bAttr; 
}St_VideoBuffChar; 
 
#define WHITE_COLOR 15 
#define SCR_WIDTH   80 
#define SCR_HEIGHT  25 
#define VIDEO_BUFF_LIMIT    (80*25) 
#define VIDEO_BUFF_BASE     (St_VideoBuffChar _far *)0xB8000000 
 
#define xy2off(x, y) ( (y)*SCR_WIDTH + (x) ) 
 
//  This pointer points to the video buffer, starting at address B800:0000 
static St_VideoBuffChar _far * s_aryVideoBuffer = VIDEO_BUFF_BASE;     
 
void TextDev_ClearScreen(void) 
{ 
    int y; 
     
	for( y = 0; y < SCR_HEIGHT; y ++ ) 
	{ 
	    int x; 
	    for( x = 0; x < SCR_WIDTH; x ++ ) 
	    { 
	        int iOffset = xy2off(x, y); 
    		s_aryVideoBuffer[iOffset].bChar = 0; 
    		s_aryVideoBuffer[iOffset].bAttr = 0; 
	    } 
	} 
} 
 
void TextDev_Out( int x, int y, const char * szText, int n ) 
{ 
    unsigned int i; 
    const char * p; 
	int iOffset = xy2off(x, y); 
 
	for( i = 0, p = szText;  
	    i < n && iOffset < VIDEO_BUFF_LIMIT;  
	    i++,iOffset++, p++) 
	{ 
		s_aryVideoBuffer[iOffset].bChar = *p; 
		s_aryVideoBuffer[iOffset].bAttr = WHITE_COLOR; 
	} 
}