embedded.c

嵌入式系统基础课件

/* ============================================================ */
/* File: EMBEDDED.C						*/
/*								*/
/* Copyright (C) 1999, Daniel W. Lewis and Prentice-Hall	*/
/*								*/
/* Purpose: An example of an embedded application program that	*/
/* runs on an IBM-PC or equivalent with a 386 or better cpu.	*/
/*								*/
/* This program must be compiled and linked into an absolute	*/
/* binary image file called EMBEDDED.BIN and put on a floppy	*/
/* diskette whose boot sector has been replaced with a copy of	*/
/* BOOTLOAD.BIN using the utility COPYBOOT.EXE.  To run this	*/
/* program, you must perform a cold boot using the floppy.	*/
/*								*/
/* Designed for use with the DJGPP port of the GNU C/C++	*/
/* protected mode 386 compiler.					*/
/*								*/
/* Modification History:					*/
/*								*/
/* ============================================================ */

#include <dos.h>
#include <pc.h>
#include "libepc.h"
#include "mtc.h"

void KeyBoard(void)
	{
	static char keyboard[] =   "Keyboard Scan Code: --" ;
	int len, col, kcol ;

	len = strlen(keyboard) ;
	col = (80 - len) / 2 ;
	SetCursorPosition(14, col) ;
	PutString(keyboard) ;
	kcol = GetCursorCol() - 2 ;

	for (;;)
		{
		BYTE8 scan_code ;

		while (!ScanCodeRdy()) MtCYield() ;
		scan_code = GetScanCode() ;

		SetCursorPosition(14, kcol) ;
		PutUnsigned(scan_code, 16, 2) ;
		}
	}

void ElapsedTime(void)
	{
	static char elapsed[] =   "Elapsed Time: " ;
	int old, len, col, tcol ;

	len = strlen(elapsed) ;
	col = (80 - (len + 8)) / 2 ;
	SetCursorPosition(15, col) ;
	PutString(elapsed) ;
	tcol = GetCursorCol() ;

	old = -1 ;
	for (;;)
		{
		unsigned long msec ;
		unsigned hh, mm, ss, fs ;

		while ((msec = Milliseconds()) == old)
			{
			MtCYield() ;
			}
		old = msec ;

		hh = msec / (60 * 60 * 1000) ;	msec %= (60 * 60 * 1000) ;
		mm = msec / (60 * 1000) ;	msec %= (60 * 1000) ;
		ss = msec / 1000 ;
		fs = msec % 1000 ;

		SetCursorPosition(15, tcol) ;
		PutUnsigned(hh, 10, 2) ;
		PutChar(':') ;
		PutUnsigned(mm, 10, 2) ;
		PutChar(':') ;
		PutUnsigned(ss, 10, 2) ;
		PutChar('.') ;
		PutUnsigned(fs, 10, 2) ;
		}
	}

int main(void)
	{
	static char welcome[] = " Welcome to Protected Mode! " ;
	static char memory[]  =     "Physical Memory: " ;
	DWORD32 kbytes ;
	int col, len ;

	enable() ;				/* Enable interrupts.	*/

	ClearScreen(0x07) ;
	SetCursorVisible(FALSE) ;

	len = strlen(welcome) ;
	col = (80 - len) / 2 ;
	SetCursorPosition(11, col) ;
	PutAttb(0x70, len) ;
	PutString(welcome) ;

	kbytes = ((DWORD32) LastMemoryAddress() + 1) / 1024 ;
	len = strlen(memory) ;
	col = (80 - (len + 6)) / 2 ;
	SetCursorPosition(12, col) ;
	PutString(memory) ;
	if (kbytes < 1024)
		{
		PutUnsigned(kbytes, 10, 0) ;
		PutString(" KB") ;
		}
	else
		{
		PutUnsigned(kbytes / 1024, 10, 0) ;
		PutString(" MB") ;
		}

	MtCCoroutine(ElapsedTime()) ;
	MtCCoroutine(KeyBoard()) ;

	return 0 ;
	}