ftoidlg.cpp

一个浮点数和整数互相转换的测试程序, 不依赖于浮点库, 效率高,适合移植于单片机.

// FtoIDlg.cpp : implementation file
//

#include "stdafx.h"
#include "FtoI.h"
#include "FtoIDlg.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// CFtoIDlg dialog

CFtoIDlg::CFtoIDlg(CWnd* pParent /*=NULL*/)
	: CDialog(CFtoIDlg::IDD, pParent)
{
	//{{AFX_DATA_INIT(CFtoIDlg)
	m_f = 0.0f;
	m_i = 0;
	//}}AFX_DATA_INIT
	// Note that LoadIcon does not require a subsequent DestroyIcon in Win32
	m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
}

void CFtoIDlg::DoDataExchange(CDataExchange* pDX)
{
	CDialog::DoDataExchange(pDX);
	//{{AFX_DATA_MAP(CFtoIDlg)
	DDX_Text(pDX, IDC_F, m_f);
	DDX_Text(pDX, IDC_I, m_i);
	//}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(CFtoIDlg, CDialog)
	//{{AFX_MSG_MAP(CFtoIDlg)
	ON_WM_PAINT()
	ON_WM_QUERYDRAGICON()
	ON_BN_CLICKED(IDC_FI, OnFi)
	ON_BN_CLICKED(IDC_IF, OnIf)
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CFtoIDlg message handlers

BOOL CFtoIDlg::OnInitDialog()
{
	CDialog::OnInitDialog();

	// Set the icon for this dialog.  The framework does this automatically
	//  when the application's main window is not a dialog
	SetIcon(m_hIcon, TRUE);			// Set big icon
	SetIcon(m_hIcon, FALSE);		// Set small icon
	m_f = -1;
	// TODO: Add extra initialization here
	
	return TRUE;  // return TRUE  unless you set the focus to a control
}

// If you add a minimize button to your dialog, you will need the code below
//  to draw the icon.  For MFC applications using the document/view model,
//  this is automatically done for you by the framework.

void CFtoIDlg::OnPaint() 
{
	if (IsIconic())
	{
		CPaintDC dc(this); // device context for painting

		SendMessage(WM_ICONERASEBKGND, (WPARAM) dc.GetSafeHdc(), 0);

		// Center icon in client rectangle
		int cxIcon = GetSystemMetrics(SM_CXICON);
		int cyIcon = GetSystemMetrics(SM_CYICON);
		CRect rect;
		GetClientRect(&rect);
		int x = (rect.Width() - cxIcon + 1) / 2;
		int y = (rect.Height() - cyIcon + 1) / 2;

		// Draw the icon
		dc.DrawIcon(x, y, m_hIcon);
	}
	else
	{
		CDialog::OnPaint();
	}
}

// The system calls this to obtain the cursor to display while the user drags
//  the minimized window.
HCURSOR CFtoIDlg::OnQueryDragIcon()
{
	return (HCURSOR) m_hIcon;
}

void CFtoIDlg::OnFi() 
{
	UpdateData();
	m_i = FtoI(m_f);
	UpdateData(FALSE);
}

void CFtoIDlg::OnIf() 
{
	// TODO: Add your control notification handler code here
	m_f = (1>2) ? 23 : 34;
	UpdateData(FALSE);
}

float CFtoIDlg::ItoF(short in)
{
	return 0;
}

short CFtoIDlg::FtoI(float in)
{
	unsigned char * p;
	unsigned char point;
	unsigned char sign;
	short res;

	//--------------------------------
	p= (unsigned  char*)∈
	point = *p;
	*p = *(p+3);
	*(p+3)=point;

	point = *(p+1);
	*(p+1) = *(p+2);
	*(p+2)=point;
	//--------------------------------
	p= (unsigned char*)∈
	sign = (*p) >> 7;
	point = (*p) << 1;
	p++;
	point += (*p) >> 7;
	res = (*p) | 0x80;
	res <<= 7;
	p++;
	res += (*p>>1);	// ?
	
	res >>= ((14+127)-point);
	if (sign)
		res = -res;

	return res;
}